The wide of this WB is very subtle to me. It looks more like fender flares which I really like the look of. Some wide bodies get a bit too aggressive looking and ruin the body lines of the NSX. This WB is probably the best I've seen.
Unofficial Big-Wheel Thread: 18/18 and 18/19 - the future for NSX tire sizes
- Thread starter stuntman
- Start date
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- Tags
- 18/18 18/19 big wheels
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- 13 September 2009
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Nice DF fenders, glad you kept the stoptechs.
Well i haven't really posted in years but, I cant help but notice the obsession with wider than necessary rear tires and staggered setups seams contrary to what the JDM tendency to go towards a square set up as this one is just one of the many examples...
http://www.speedhunters.com/2013/12/ultimate-nsxesprits-time-attack-monster/
they run 265/35r18 on all 4 corners pushing 700hp and 500lbs of TQ on a fully built race car with the engine rotated and are able to hold track records with that set up.
Although I have had my share of track days in NSX's and porsches and have raced in the one lap of America and i cant even count how many go-kart TAG 125cc races many years ago.. I will clearly state that I have allot less experience than some of the people on this forum, but I'm sure we may all agree no one in the US has anywhere near the obsession nor experience with the NSX chassis as the JDM market, the amount of knowledge and experience from many years of JGTC racing and tuners such as TODA and HKS must have 100 times the experience as anyone in this whole country. there must be literally hundreds of NSX race cars over there more than here to learn from.
I must also immediately state Billy is definably is one of the top NSX tuners in the US and I am not looking to directly disagree with Billy on or off this form as we have discussed this topic recently on the phone, but I am still seeking some understanding of why the JDM market seems satisfied with narrower width tires.
that being said and for whatever its worth, can someone explain why so many JDM cars run 255 or 265 max rear widths on fully built racecars with insane power?
As far as everything I have been able to research the weight of the car has a huge effect on tire tread and tire diameter will only either widen or lengthen the contact patch relative to tire pressure and the amount of weight the car can efficiently flatten the tire, taking that into effect what it seams we are always looking for (and i may be wrong) is traction while accelerating out of a turn, or breaking traction, in which the traction necessary to accelerate a car out of a turn or stopping, needs more froward traction where a longer patch would be better and road holding where a wider patch helps, but when we keep in mind the most acceleration will be applied one the car has already started pushing forward needing longer contact patch and less of a wide contact patch. yes wide may equal maximum lateral G's at the cost of breaking and acceleration relative to the effective contact patch. and no I don't believe narrow bicycle tire are the solution... lol.... but its all relative we cant install dump truck tires either and expect best performance.
on a 3000lb car with a 285 295 or 305 or so, sure lots of lateral patch grip may be achieved but my gut tells me the acceleration under power while straightening the car out and getting on the gas coming out of the apex with the reduced long patch traction will suffer.
And with so many people talking about TCS issues (which is ancient and almost worthless anyway) I would be way more concerned about Gear ratios which will be drastically negatively effected with even larger diameter tires and gear ratios http://tire-size-conversion.com/gear-ratio-calculator/ will give you your effective gear ratio with different setups. I hope people are aware that if install 4.23 gear ratios but also run bigger than stock 275-40-17 (25.6' diameter) tires you are effectively almost back to where you started with the 4.06 gears in terms of acceleration, if you go even bigger up to 275-40-18 (26.7" diameter) you will be at 3.80 gear ratio which will be substantially slower than stock, using bob butlers acceleration estimated 1/4 mile numbers if you go from 4.06 to 4.23 gears you gain gain .2 to .3 of a second then in the case of the tire sizes being mentioned here it would mean 4.06 to 3.80 gears could lose .3 to .4 of a second which is insane it would put a stock NSX running 14.2 instead of 13.8, think about that for a second. Not to mention larger diameter tires will push your 28lbs tires one inch even further away from the center than what most people already know negatively impacts RWHP, In my rolling inertia calculations a 1" increase in tire diameter alone from 25.5 to 26.6" means 2 to 3 RWHP less, add that to the gear ratio losses and its a downhill slope only people running Forced induction should consider.
Although I have been running 275 rears for 9 years now, which may have made sense when my car was 3000 lbs, but now with weight reduction down to 2575 I cant help but think that my contact patch has been reduced.
So my question becomes, if a NSX-R ran well at 28xx lbs with 255 rear tires and the tire technology has evolved, and many of us have done weight reduction substantially lighter than NSX-R, then the 255 now should be more than sufficient, taking into consideration 265 tires seem to be enough on a 600HP JDM race car.
To be honest I'm considering going to 245 rear tires if I am N/A and will take the plunge under 2500 lbs.
heres some very basic explanation/discussion on the physics forums on the topic
https://www.physicsforums.com/threads/how-does-traction-compare-to-the-width-of-a-tire.587766/
I'm all for wider tires at the front and am highly interested in achieving wider fronts but not if they are allot taller a huge issue not being talked about here is if you increase diameter of front means you are raising the front of the car, which also means you have to lower the suspension even more to not completely throw off the weight balance of the chassis and lowering the front more than we have to now means less shock travel and bring us back to now you have to raise the rear equally with larger tires to balance it out and your back to horrendous gear ratios. i think getting the tires to fit is only the tip of the ice berg in the negative side effects all over
Another thing to note is that although newer cars run wider tires, but before we follow trend, we have to acknowledge they are all huge heavy pigs that are completely unrelated to our chassis, I like to wonder if all that weight is really necessary today, or if is it just because the market demands high HP and manufactures know that if they don't also make these cars substantially heavy at almost 4000lbs and add all the computer help they can get, the buyers would kill themselves within hours of leaving the dealership. proof of this manufactures safety measure may be that both the M6 and Corvette gained around 400-500lbs last year I believe for no other reason than to effectively "dummy proof" their 100hp gain. Not to mention buyers just automatically think wider tires means a better handling car, which could not be further than the truth.
another very good read and reference for performance and relative tire sizes and car weight
http://www.superstreetonline.com/features/news/0708-sccp-lateral-g-skidpad-testing/
http://www.speedhunters.com/2013/12/ultimate-nsxesprits-time-attack-monster/
they run 265/35r18 on all 4 corners pushing 700hp and 500lbs of TQ on a fully built race car with the engine rotated and are able to hold track records with that set up.
Although I have had my share of track days in NSX's and porsches and have raced in the one lap of America and i cant even count how many go-kart TAG 125cc races many years ago.. I will clearly state that I have allot less experience than some of the people on this forum, but I'm sure we may all agree no one in the US has anywhere near the obsession nor experience with the NSX chassis as the JDM market, the amount of knowledge and experience from many years of JGTC racing and tuners such as TODA and HKS must have 100 times the experience as anyone in this whole country. there must be literally hundreds of NSX race cars over there more than here to learn from.
I must also immediately state Billy is definably is one of the top NSX tuners in the US and I am not looking to directly disagree with Billy on or off this form as we have discussed this topic recently on the phone, but I am still seeking some understanding of why the JDM market seems satisfied with narrower width tires.
that being said and for whatever its worth, can someone explain why so many JDM cars run 255 or 265 max rear widths on fully built racecars with insane power?
As far as everything I have been able to research the weight of the car has a huge effect on tire tread and tire diameter will only either widen or lengthen the contact patch relative to tire pressure and the amount of weight the car can efficiently flatten the tire, taking that into effect what it seams we are always looking for (and i may be wrong) is traction while accelerating out of a turn, or breaking traction, in which the traction necessary to accelerate a car out of a turn or stopping, needs more froward traction where a longer patch would be better and road holding where a wider patch helps, but when we keep in mind the most acceleration will be applied one the car has already started pushing forward needing longer contact patch and less of a wide contact patch. yes wide may equal maximum lateral G's at the cost of breaking and acceleration relative to the effective contact patch. and no I don't believe narrow bicycle tire are the solution... lol.... but its all relative we cant install dump truck tires either and expect best performance.
on a 3000lb car with a 285 295 or 305 or so, sure lots of lateral patch grip may be achieved but my gut tells me the acceleration under power while straightening the car out and getting on the gas coming out of the apex with the reduced long patch traction will suffer.
And with so many people talking about TCS issues (which is ancient and almost worthless anyway) I would be way more concerned about Gear ratios which will be drastically negatively effected with even larger diameter tires and gear ratios http://tire-size-conversion.com/gear-ratio-calculator/ will give you your effective gear ratio with different setups. I hope people are aware that if install 4.23 gear ratios but also run bigger than stock 275-40-17 (25.6' diameter) tires you are effectively almost back to where you started with the 4.06 gears in terms of acceleration, if you go even bigger up to 275-40-18 (26.7" diameter) you will be at 3.80 gear ratio which will be substantially slower than stock, using bob butlers acceleration estimated 1/4 mile numbers if you go from 4.06 to 4.23 gears you gain gain .2 to .3 of a second then in the case of the tire sizes being mentioned here it would mean 4.06 to 3.80 gears could lose .3 to .4 of a second which is insane it would put a stock NSX running 14.2 instead of 13.8, think about that for a second. Not to mention larger diameter tires will push your 28lbs tires one inch even further away from the center than what most people already know negatively impacts RWHP, In my rolling inertia calculations a 1" increase in tire diameter alone from 25.5 to 26.6" means 2 to 3 RWHP less, add that to the gear ratio losses and its a downhill slope only people running Forced induction should consider.
Although I have been running 275 rears for 9 years now, which may have made sense when my car was 3000 lbs, but now with weight reduction down to 2575 I cant help but think that my contact patch has been reduced.
So my question becomes, if a NSX-R ran well at 28xx lbs with 255 rear tires and the tire technology has evolved, and many of us have done weight reduction substantially lighter than NSX-R, then the 255 now should be more than sufficient, taking into consideration 265 tires seem to be enough on a 600HP JDM race car.
To be honest I'm considering going to 245 rear tires if I am N/A and will take the plunge under 2500 lbs.
heres some very basic explanation/discussion on the physics forums on the topic
https://www.physicsforums.com/threads/how-does-traction-compare-to-the-width-of-a-tire.587766/
I'm all for wider tires at the front and am highly interested in achieving wider fronts but not if they are allot taller a huge issue not being talked about here is if you increase diameter of front means you are raising the front of the car, which also means you have to lower the suspension even more to not completely throw off the weight balance of the chassis and lowering the front more than we have to now means less shock travel and bring us back to now you have to raise the rear equally with larger tires to balance it out and your back to horrendous gear ratios. i think getting the tires to fit is only the tip of the ice berg in the negative side effects all over
Another thing to note is that although newer cars run wider tires, but before we follow trend, we have to acknowledge they are all huge heavy pigs that are completely unrelated to our chassis, I like to wonder if all that weight is really necessary today, or if is it just because the market demands high HP and manufactures know that if they don't also make these cars substantially heavy at almost 4000lbs and add all the computer help they can get, the buyers would kill themselves within hours of leaving the dealership. proof of this manufactures safety measure may be that both the M6 and Corvette gained around 400-500lbs last year I believe for no other reason than to effectively "dummy proof" their 100hp gain. Not to mention buyers just automatically think wider tires means a better handling car, which could not be further than the truth.
another very good read and reference for performance and relative tire sizes and car weight
http://www.superstreetonline.com/features/news/0708-sccp-lateral-g-skidpad-testing/
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And that is why I keep my OEM 15/16" wheels with Bridgestone RE-71R tires on my 500WHP 2650lb NSX... but to be fair, I run 15mm front spacers (need to go to 25mm front) and 40mm rear spacers.
I've been thinking about buying spare 15/16" wheels and trying to mill them down to look a bit better. Then, I would destructively test a front and rear to see what the reduced load limits are.
Oops - Sorry. Off topic. I should start an Unofficial Small-Wheel Thread.:biggrin:
Dave
I've been thinking about buying spare 15/16" wheels and trying to mill them down to look a bit better. Then, I would destructively test a front and rear to see what the reduced load limits are.
Oops - Sorry. Off topic. I should start an Unofficial Small-Wheel Thread.:biggrin:
Dave
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A lot of people are enamored by "JDM Tuners" and feel they are gods. They do a lot of things differently, some things innovative and ingenious, and some things wrong. You really need to look at the whole picture of the industry and culture to understand why they do what they do. They are in no way 'superior' to the US race shops/tuners, but tuning is deep in their culture and they do some pretty cool things over there.
While the Esprit NSX is really nice and has some awesome components (proper racing gearbox, longitudinal layout, twin turbos, etc... it's not as fast as the FXMD NSX with its stock suspension geometry, stock gearbox and engine configuration). Don't get me wrong, the Esprit NSX has much better components and is better built than the FXMD car, and it probably cost 4-5X as much money as the low budget FXMD guys have, but the FXMD guys can take a dollar pretty darn far and know where to focus their efforts with their limited budget. I'd love to drive the Esprit NSX and would probably go faster than their current driver (fly me over if you guys are reading this) but they are behind in a few areas.
Totally DISAGREE. There are very bright people here in the States that know just as much as any shop on the NSX chassis. I wonder how many JDM tuners had the NSX's suspension CMM measured? JGTC cars are so far out of the realm of the stock NSX's geomety and design that its like relating a Toyota Corolla NASCAR Cup car to the Corolla in your driveway.
I drive the country's fastest NSX and arguably the fastest US Time Attack car; one of the fastest in the world, and am heavily involved with the design and engineering of the car, but I'm not sure I would call myself an "NSX tuner".
Why does the JDM market seem to be satisfied with narower width tires?
Answer: The culture and availability. You need to take a brief history lesson and look at the country's history. To make things simpler so I don't spend hours writing a novel,tire technology, diameter, and width have all increased over time, from the days where cars were severely under-tired and under-braked. In the late 80s, Japanese auto mfgs had a 'pact' or 'gentlemen's agreement' to limit the advertised HP of their cars to 276hp to prevent a horsepower war and since their highest speed limit was ~60mph.
In the 90's, most performance cars were making the advertised 276hp (and often well over; such as Skylines and Supras). This was a major factor the NSX was born with a 270hp 3.0L V6 motor to compete against Ferrari's 296hp 3.4L V8 and Chevrolet's 375hp 5.7L ZR1. With relatively low power, the NSX only needed 205/225s to compete with Ferrari's 215/255 and Chevy's 275/315s. Despite some manufacturers making well over the 'agreed' 276hp; most cars were not as powerful or have tires as wide as Vipers, Vettes, 355/360 Ferraris, Porsches, etc... There weren't many of these cars in Japan in the 90's either; so domestic (JDM) tire manufacturers never had to supply the size of tires of American and European sportscars. Look at any Japanese car from the 90's, it's rare to see anything wider than a 245 width tire and I don't recall anything having wider than a 275.
In the early 2000's, Ferrari's, Vipers, Vettes, and Porsches were running 275-335 width tires for nearly a decade, while Japanese cars were still rated at 276hp and had tire sizes in proportion to that lower power level. Some manufacturers were pushing it, like Honda did with the NSX in 1997 to rate the 3.2L at 290hp to try to make the car not a flop in the rest of the world where most NSXs were sold. It wasn't until ~2003 that Japan got rid of the horsepower pact and started making more powerful cars.
SO: All of the above means that there weren't many high HP factory cars in Japan, and the culture revolved around these smaller tires.
PRESENT DAY: In the boom of "Time Attack" in the early 2000s, most Japanese tire manufacturers (Yokohama, Bridgestone) were in a mini tire-war and used motorsports compounds in their "R"-compound and "street" tire molds to cheat the rules of Time Attack that mandated the use of "street tires". The widest commonly used tire at this time was a 265. While Yokohama did make a 315 A048 at the time, they never really made these 'special' soft compound tires in this size since the 315 was for a Porsche market outside the country. A great example was when HKS came to the US and destroyed our lap record with a set of these soft 265-width 'cheater' tires. Due to most unlimited-class cars being AWD, they didn't need a tire too much wider than a 265 to put power down though 4 tires, when the compound was that sticky and only lasted 2-3 laps. **I ran a set of these 'special' HKS A048 tires 265-square setup on a 700whp TT 350Z as well as the FXMD NSX. The grip was unbelievable and it truly was a one lap wonder tire, and had more grip than a traditional 'r-compound' 335/30-18 rear tire.
RWD TA cars are almost all front-engine and were at a huge disadvantage to the unlimited AWD cars to try to put down similar power levels through 2 tires. Since they are front-engine, a 'square' tire setup is often preferable. Because of this, the 265 being the 'standard' for the widest tire in TA, 265/35-18 was THE tire size to use and typically the only size made in the super soft compounds, whether you are FR, MR, or AWD. This is the reason the Esprit NSX uses a square setup. This inherently disadvantages RWD cars and was a major factor in why FXMD did not spend thousands of dollars to race in the World Time Attack, that put any RWD car at such a disadvantage.
I forget exactly when, but I want to say around 2010-12, the Japanese tire manufacturers started making their super soft tires (and more tires in general) in a 295 size. Guess what? A RWD S15 almost won the event overall since there was more grip to put the power down through 2 tires. This wider tire did not really help AWD cars, and i'm sure there was politics for quite some time by the heavy hitters like HKS to keep the special tires at 265, to advantage their EVOs, WRXs, and GTRs.
295s are much better but still not quite enough to give RWD cars an even playing field. I suspect 315s would do it but the special tires are yet to be made in that size.
If I didn't bore you to death and you actually read all of this, there's a reason for everything. The best tires, and only real options in japan are 265 or 295 18" tires, which is what dictates what people run. Due to the NSX's weight distribution, i'm sure if they made a 245 super soft front tire, the Esprit would run a 245/265 or 245/295 setup, but since 265/265 is readily available and one of the best options, thats what they set their car up to. You an make a square setup work on an NSX, but in order to balance it out, you would likely compromise other areas of the setup rather than sizing your tires correctly.
The whole point of this thread is:Determine what the use of your car is going to be, then determine what characteristics you want from a tire, then pick a tire that fits these needs, the tire and purpose of the tire will determine its ideal size (Track use & low power would use a smaller sticky tire than a street car that has a lot of power, needs to be good in the rain, and good on track), then pick a wheel size accordingly
Most people do this backwards. They pick a wheel they like with a given size, then try to find tires that fit their needs and realize there are not many options. I created this thread to open up the tire selection for the NSX that allows for the newest tire technology and greatest tires to fit on an NSX. Yes wider fenders will be needed (in prototype phase), and yes the overall diameter is increased a bit; but on track, I would take a higher performing tire with a greater OD than a lower performing tire with the stock OD. You make up more time in the corners than the straights. You can always go to a higher numerical final drive to further improve acceleration and to offset the larger diameter tire. Or if you're FI, the increase in diameter does not matter, but the sizes in this thread still allows for ABS and TCS functionality.
Yes contact patch does not change in size with the car weight and tire pressures constant. But wider tires allow for lower running pressures which increases contact patch.
Wider tires and larger diameter tires increase the tire VOLUME, which makes them resist overheating and allows for more laps at speed rather than wasting time and your money doing cooldown laps to keep the tires under you. While larger tires cost more, they should last longer due to the increase in volume, saving $.
*It depends on what tires you run and what the purpose you need the car for.*
-If you're running racing slicks, and are doing a 30-minute session or race and have 240whp, a 245 width tire is fine.
-If you need a good dual purpose tire that gets you to the track, you can beat on it, and drive home (Michelin PSS, AD08, RE11), and are FI with say 450whp, and don't want to only do a few laps at a time before they overheat and the car becomes a handful, increasing the tire volume (width and diameter) will greatly help this; and this is the boat many are in.
TCS is pretty worthless, however the newer ABS is pretty good; which is why the tire sizes i've been listing work well with both. As far as gear ratios, if you are that concerned, then change your final drive ratio to a 4.23 or 4.40. If the budget does not allow, then (just like everything else) you need to look at your constraints and choose the best course of action.
You have a light weight, low powered car. If streetability of your tires don't matter and pure lap times do, then go with smaller race tires. If you NEED to have a good streetable tire, then you'll need to go larger. Again, i'll take a better performing tire with a larger diameter over a lower performing tire with the stock diameters.
*Yes going from a 275/40-17 to a 275/35-19 does change the effective ratio from a 4.06 to a 3.80 and the acceleration from 45-70mph is reduced, from 70-terminal velocity it's a bit of a wash. You would have to back to back both with proper data analysis to see what the grip differences are for a peak lap and over the course of a stint to see what the tradeoffs are. I am going to do this with my 235/275 17/18 and 18/19 tire combinations, both with Nitto NT05 street tires....eventually.
You could put a 4.23 in which will effectively make my 18/19 setup a 3.94 final drive, almost a wash to the original 4.06, or with a 4.40 which will effectively turn it in to a 4.11 ratio. You need to decide what power levels you are going to have, the tires you want to run, and the purpose for them to decide. For me, I will eventually have 500whp+, I WANT street tires that I can daily and track. For me, the direction is these larger sizes, and again, I will quantify them on track once my car's done and before the turbo is installed.
It depends on the tires you want to run. A 265 "super special" tire does not = a 265 off the shelf street tire.
The NSX-R would have been faster with wider versions (front and rear) of the same model tire (assuming they made the same bespoke tire in a larger 235/275). There are numerous videos of the NSX-R sliding around way too much on fast laps, even the videos that you emailed me.
Way too many variables that are unanswered. Was the rear tires being over loaded and overheated, was there not enough heat being generated thus causing the oversteer, was the camber ideal to begin with, what about the camber gain? -it's too complicated to answer simply wider = more grip. There's a lot more to it.
Raising the front or rear of the car will not have any significant effect on the front-rear weight distribution; due to the low CG and the length of the wheelbase. However it could change your front to rear roll centers and that can induce understeer by changing your roll couple distribution. Nose down typically improves front grip.
2,800lb racecars run 305/345 width super sticky racing slicks. -In order to generate grip. But due to the tire size:weight relationship, it takes some time to get heat in the tire for them to make grip. Going too wide and not loading a tire enough will not allow the tire to operate in its proper range and you will have less grip. So another factor in determining tire size is to make sure they are large enough to not overheat, but not too large that you can't get them up to temp and in to their peak operating range.
That's enough for one night...
Dayummm, stuntman
now that's a mic drop:applause::listening_headphone
now that's a mic drop:applause::listening_headphone
Billy, thank you for the information and your time to seriously answer my questions and yes I read it all, twice.
I understand your need to accommodate the larger tire sizes the market has evolved to and will happily help you with the test fittings you need to do.
Thank you for schooling me on the 265 tire limitations and history I was not aware of as well as a few other things.
The tuner comment I made was just a generalization, your knowledge of the NSX is quite vast.
So correct me if am wrong, out of all my concerns the most important would be that for N/A applications, anyone considering these larger diameters may need/want to go to a 4.23 or 4.40 gears or be ready to accept a reduction in acceleration from ending up with a 3.8 gear ratio and increased diameter size & weight and rotating inertia RWHP loss.
for FI it is probably irrelevant
Iv been on the dyno 4 times in past few weeks and ordered a set of wheels to try 245 or 255 rear in few weeks. I want to set up a dyno day here in ft lauderdale at my freinds shop and also do a test swapping a couple different NSX's rear wheel/tire sets onto the same NSX to see the differences in HP, and acceleration speed due to variable diameters. Another test i would like run is to set up place we could test a couple different tire setups on the same turn or short series of turns at 50-60 MPH. We can set up a series of cones and use 3-4 different wheel/tire setups if people don't mind showing up with their NSX and letting us borrow/swap wheels for the test onto a the same NSX used for every test. This way we can keep driver (you) and car constant. allot easier to ask someone to let us borrow/test their wheels/tires than their car. we could also just do a track day using different borrowed setups for each session and data log.
Out of curiosity, what are your thoughts about the tire options in 285-30-18? retains a 25" Diameter and has quite a few sticky tires.
http://www.tirerack.com/tires/TireS...rformance=ALL&width=285/&ratio=30&diameter=18
and that way 4.23 will do what it was intended to do
i too will go FI very soon, I sold my love fab turbo that I bought and never installed, and now have a BBSC on the shelf that I have not installed yet, I'm still contemplating losing the incredible reliability of the NSX.
I highly respect what FXMD has done and all your accomplishments have been astonishing.
Whether that equals the JDM tuners efforts is a discussion that can not be had unless we has two cars on the same track. Nor would I even chance discrediting FXMD for all that you guys have contributed to NSX history in the US.
I hope you guys continue to tweak and develop the car even more its amazing. I would love to see what crazy fast time that car could do on the nurburgring.
I understand your need to accommodate the larger tire sizes the market has evolved to and will happily help you with the test fittings you need to do.
Thank you for schooling me on the 265 tire limitations and history I was not aware of as well as a few other things.
The tuner comment I made was just a generalization, your knowledge of the NSX is quite vast.
So correct me if am wrong, out of all my concerns the most important would be that for N/A applications, anyone considering these larger diameters may need/want to go to a 4.23 or 4.40 gears or be ready to accept a reduction in acceleration from ending up with a 3.8 gear ratio and increased diameter size & weight and rotating inertia RWHP loss.
for FI it is probably irrelevant
Iv been on the dyno 4 times in past few weeks and ordered a set of wheels to try 245 or 255 rear in few weeks. I want to set up a dyno day here in ft lauderdale at my freinds shop and also do a test swapping a couple different NSX's rear wheel/tire sets onto the same NSX to see the differences in HP, and acceleration speed due to variable diameters. Another test i would like run is to set up place we could test a couple different tire setups on the same turn or short series of turns at 50-60 MPH. We can set up a series of cones and use 3-4 different wheel/tire setups if people don't mind showing up with their NSX and letting us borrow/swap wheels for the test onto a the same NSX used for every test. This way we can keep driver (you) and car constant. allot easier to ask someone to let us borrow/test their wheels/tires than their car. we could also just do a track day using different borrowed setups for each session and data log.
Out of curiosity, what are your thoughts about the tire options in 285-30-18? retains a 25" Diameter and has quite a few sticky tires.
http://www.tirerack.com/tires/TireS...rformance=ALL&width=285/&ratio=30&diameter=18
and that way 4.23 will do what it was intended to do
i too will go FI very soon, I sold my love fab turbo that I bought and never installed, and now have a BBSC on the shelf that I have not installed yet, I'm still contemplating losing the incredible reliability of the NSX.
I highly respect what FXMD has done and all your accomplishments have been astonishing.
Whether that equals the JDM tuners efforts is a discussion that can not be had unless we has two cars on the same track. Nor would I even chance discrediting FXMD for all that you guys have contributed to NSX history in the US.
I hope you guys continue to tweak and develop the car even more its amazing. I would love to see what crazy fast time that car could do on the nurburgring.
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Billy... great post. It was long, thanks for taking the time.
I don't think I posted here but mainly because of this thread and my need to fit wheels over my 362mm ceramics, I did do exactly what was suggested ob this post And am running 225/40/18 and 275/35/19 Pilot super sports. No track work yet but now that the track season is here again I will be. A few pics to show sizing... sorry if they are a bit too artsy.
[/URL][/IMG]
- - - Updated - - -
By the way... I had the TCS light kick on momentarily once, not sure if there is a legit issue but I have barely driven the car since these went on.
I don't think I posted here but mainly because of this thread and my need to fit wheels over my 362mm ceramics, I did do exactly what was suggested ob this post And am running 225/40/18 and 275/35/19 Pilot super sports. No track work yet but now that the track season is here again I will be. A few pics to show sizing... sorry if they are a bit too artsy.
- - - Updated - - -
By the way... I had the TCS light kick on momentarily once, not sure if there is a legit issue but I have barely driven the car since these went on.
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Yes that is the tradeoff. The increased tire selection and the use of better tires could easily outweigh the negatives of the acceleration (on track), it all depends on the PURPOSE OF THE CAR AND TIRE.
Please define what the role of your car and tires are. Track car, weekend toy/occasional track, daily driver, daily driver that you will track ocasionally, etc...
If you plan on running street tires, 245s are not going to be wide enough. There are tons of 2,600lb S2000s that run 255s-275 all around and they can still overheat their tires. The equivalent of a 255 square setup for an S2000 is a 235/275 for the NSX (weight distribution and volume wise).
The back to back dyno test would be a valuable thing to do; if you can swap tires quickly and get the dynos done as close together as possible so the weather conditions do not change. But this will require a proper 3-4 pulls per wheel setup to see the trend of consistency and power loss as engine temps rise.
I would love to be apart of that handling test but unless everyone brings brand new sticker tires, it will be somewhat of a pointless test to use tires with varying heat cycles, ages, tire wear, etc...
285/30-18 is slightly outside the OEM % but could work. There are some decent tires in that size, but still not many and you need to make sure there is a proper size front tire in the same compound. I know you want to mix and match tires F-R, but I really don't think it's a great idea and don't recommend it.
TURBO - your car looks amazing and I really think those tire sizes LOOK awesome and proper. The sidewall heights look proportional and thick enough to not be harsh riding, and i can't wait to get mine on! Did you TCS light come on when you were spinning the tires?
Billy are you getting the PSS also? Or would you get something like an AD08R if tread wear was not a concern? For intended street/track use on a 500whp NSX-
I'm setting the car up for weekend use & occasional track days not a track dedicated car.
If the tires you are trying to fit are really that much sticker than what is available to us now, than sign me up
For the purpose of trying to figure out the effects of this on N/A performance, are we on same page on any of the following the following scenarios?
using 1/4 mile acceleration just for the purpose of understanding the effect of the options.
So obviously these are all estimates, but I used very conservative estimates on the low side as we have all seen much more aggressive estimates out there.
Part A - gear ratios
increasing tire diameters
25" diameter oem 4.06 installing 4.23 type-r gears = .17 difference = .15 to .25 sec 1/4 mile acceleration improvement = similar effect of 10-15hp
effect of 26.5" diameter on oem 4.06 gears becomes 3.80 = .26 difference = .15 to .3 sec 1/4 mile acceleration reduction = similar to losing 13-20hp
Difference from lowest to highest = .43 gear ratio = .3 to .55 seconds = theoretically equivalent to 23-35hp
Part B - rotating inertia
Reducing 5-6 lbs per drive wheel/tire of inertia = .75hp per pound = 3-5 rwhp gained = .05 to .075 sec 1/4 mile improvement
Adding 5-10 lbs per rear wheel = .75 per pound = 4-7 rwhp reduction = .05 to .115 sec 1/4 reduction
Difference from lightest to heaviest 10-16 lbs per wheel/tire = .175 to .225 seconds 1/4 mile acceleration
Part C = example of overall car weight 2800lb w/ 300 hp = 9.3lbs per hp
Ce28n in OEM size with 255 tires Reduce 22 lbs of un-sprung weight = equivalent of 2.5hp gain = .04 sec 1/4 mile gain
larger 19" and 275 tires Add 30 lbs of un-sprung weight = equivalent of 3.2hp loss = .05 sec 1/4 loss
Difference from lowest to highest 55lbs overall vehicle weight = 2778lbs vs 2830lbs = equivalent to 5.7 hp = .09 sec 1/4 mile gain
Part D - handling and suspension response
reducing 5 - 6 lbs per corner of unsprung weight
adding 5-7 lbs per corner of unsprung weight
difference is 10-15 lbs per corner
Billy, taking all this into consideration going to larger wheels tires is all opposite to common theories and goes against just about everything Colin Chapman has ever wrote in your effort to find the stickiest tires possible, thus why I am intrigued but very confused by this approach. BTW I am not disagreeing just to disagree, maybe I just not aware or understand exactly how much stickier these new tires really are, because by the time all this is taking into consideration its adds up to around .5 to .75 of a second of 1/4 mile time on a N/A car, which is allot and yes gear ratios solve half the problem but still leaves the weight issues unresolved.
i am enjoying this discussion and hope you are also.
4/17/15 .... I edited this post since I has a decimal point in the wrong place in the rolling inertia calculation and was also off by a tenth in the gear ratio calculation
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I currently have NT05s, which I set the unofficial "stock power, stock aero" NSX time at Buttonwillow on. The PSS is a better tire in the rain and under all conditions as the NT05 and AD08R, however i'm not sure which one is outright quicker on track. Since the PSS is soo good on the street, it's my go-to tire.
A 245 or 255 street tire or R-comp is not wide enough or have enough volume to run a 15-20 minute session at the limit without overheating. You need to go to a stickier tire, or a larger (width and diameter) tire. 265-275 is kind of the minimum and wider would increase this heat and load capacity.I'm setting the car up for weekend use & occasional track days not a track dedicated car.
For the purpose of trying to figure out the effects of this on N/A performance, are we on same page on any of the following the following scenarios?
using 1/4 mile acceleration just for the purpose of understanding the effect of the options.
So obviously these are all estimates, but I used very conservative estimates on the low side as we have all seen much more aggressive estimates out there.
Part A - gear ratios
increasing tire diameters
4.06 to 4.23 = .17 difference = .2 to .3 sec 1/4 mile acceleration improvement = similar effect of 10-15hp
4.06 to 3.80 = .26 difference = .25 to .4 sec 1/4 mile acceleration reduction = similar to losing 13-20hp
Difference from lowest to highest = .4 to .7 seconds = 23-35hp
Part B - rotating inertia
Reducing 5-6 lbs per drive wheel/tire of inertia = .75hp per pound = 3-5 rwhp gained = .75 to .1 sec 1/4 mile improvement
Adding 5-10 lbs per rear wheel = .75 per pound = 4-7 rwhp reduction = .1 to 1.25 sec 1/4 reduction
Difference from lightest to heaviest 1.75 to 2.25 seconds 1/4 mile acceleration
Part C = overall car weight 2800lb w/ 300 hp = 9.3lbs per hp
Ce28n in OEM size with 255 tires Reduce 22 lbs of un-sprung weight = equivalent of 2.5hp gain = .05sec 1/4 mile gain
larger 19" and 275 tires Add 30 lbs of un-sprung weight = equivalent of 3.2hp loss = .05 sec 1/4 loss
Difference from lowest to highest 5hp = .1 sec 1/4 mile gain
Part D - handling and suspension response
reducing 5 - 6 lbs per corner of unsprung weight
adding 5-7 lbs per corner of unsprung weight
difference is 10-15 lbs per corner
Billy, taking all this into consideration going to larger wheels tires is all opposite to common theories and goes against just about everything Colin Chapman has ever wrote in your effort to find the stickiest tires possible, thus why I am intrigued but very confused by this approach. BTW I am not disagreeing just to disagree, maybe I just not aware or understand exactly how much stickier these new tires really are, because by the time all this is taking into consideration its adds up to around 1 second 1/4 mile time on a N/A car, which is allot and yes gear ratios solve half the problem but still leaves the weight issues unresolved.
i am enjoying this discussion and hope you are also.
Having swapped wheels that vary 4-5lbs per wheel, I did not notice on data or relative to competitors a 3-5whp loss. I'm not sure where you got your formulas from, but in the real world the added unsprung and rotational weight does not even add up to a few tenths on a ~2 minute racetrack. You never want to add unsprung or rotational weight if you can help it, but it does not have the impact that your math suggests. At least not on heavy 2,700lb street cars (yes 2,700lbs is heavy when compared to a formula car).
TIRES ARE EVERYTHING. You can take a substantial rotational and unsprung weight penalty for a small improvement in the tires; but in racing tires are usually constant. Any race team would kill for small advantages from tires, which is why you see so much money spent in racing when there are competing manufacturers. A set of Michelin 'special' LeMans tires run $10,000 a set, and they are worth every penny. If you keep the tire constant, then yes you want to reduce weight every way you can; but if going even smaller or larger in size allows you to run a clearly superior tire; that would be the driving force in determining your tire size.
To 'have your cake and eat it too'; a smaller diameter 16-17" wheel with a 215/275 or 235/295 street tire would be ideal for you, but tire availability dictates what sizes the tire you want (which is the best street tires on the market) and that's the whole purpose of the thread. If you want to run racing slicks, 245-255 rear tires may be fine, and run them in a smaller diameter for better gearing and weight.
You need to define what the purpose is. If its purely to set a SINGLE lap; then you can get away with a lighter, narrower rear tire which will be quicker for a short period of time but then the tire needs to be cooled back down before beating on them again. this is why Japanese Time Attack cars (especially AWD) were okay with 265 width tires, because they only did a lap or two at a time and then would switch out to new tires. Plus the cars would tend to overheat after a lap anyway, so it's part of the culture. ***but most people like to do full 15-20 minute sessions without overheating their rear tires and having the car become a handful to drive, thus you need wider and larger tires.
Then there are brakes. 13" brakes are pretty much the standard while there are a few systems (like PFCs) that run 14" rotors. Larger rotors won't help your brake any later but like wider and larger tires, they improve the VOLUME and capacity of the brakes. For me, going to a larger diameter rotor will allow me to increase the thermal capacity of the brake system to the point where hopefully I can run street pads on the track without overheating them. While proper ducting and aggressive race pads would probably suffice on an NA car with stock brakes or 13" BBK, I don't want to swap pads at the track just like I don't want to swap tires at the track in my daily driven NSX. I basically want to create a GT3 RS or 458 Speciale which has streetable tires and brakes that get you to the track and home, but will hold up to all of the abuse thrown at them on track. In order to do that from a tire and brake standpoint, you need to make them larger.
Unless you already have the driving ability to get every last tenth out of the car and you are trying to break some street tire record, it would be far better to have a larger/wider tire that lasts an entire session for you to get your moneys worth and added seat time to work on your craft.
Instead of suffering from analysis paralysis; it may be better to state what your goals are, what your limitations are, and then ask for advice to achieve those goals rather than blowing some numbers out of proportion.
0.02
If we're purely talking about performance tires, then two factors I haven't seen discussed yet that play an important role in these discussions is sidewall stiffness (they do vary quite a bit between "performance tires"), and also track temps themselves.
As I've reached my 30's, I'm not one of those that enjoys tracking in ambient temps over 90F. I've played with IR cameras in the past (and posted pics of my IR NSX rear tires on this forum) to look at tire temps. These days four individual IR cameras mounted in the fender liners and pointing at your tires taking data in real-time is affordable for most if you are really into improving your track times. Track temps vary drastically, and directly affect maximum tire temps. I can get away with a slightly narrower tire in my region than someone in the South West with an identical setup as my car.
Also, sidewall stiffness plays a large role in tire temps. There are very few owners on here that remember what the OEM 15/16" Yokohamas felt like, but they had stiffer sidewalls than even todays ZII Starspec and the Kumho XS's I've run in the past. The yokos were specifically designed for the NSX, but I haven't had a fresh set in so long that I can't compare to my new RE-71R's.
As I've reached my 30's, I'm not one of those that enjoys tracking in ambient temps over 90F. I've played with IR cameras in the past (and posted pics of my IR NSX rear tires on this forum) to look at tire temps. These days four individual IR cameras mounted in the fender liners and pointing at your tires taking data in real-time is affordable for most if you are really into improving your track times. Track temps vary drastically, and directly affect maximum tire temps. I can get away with a slightly narrower tire in my region than someone in the South West with an identical setup as my car.
Also, sidewall stiffness plays a large role in tire temps. There are very few owners on here that remember what the OEM 15/16" Yokohamas felt like, but they had stiffer sidewalls than even todays ZII Starspec and the Kumho XS's I've run in the past. The yokos were specifically designed for the NSX, but I haven't had a fresh set in so long that I can't compare to my new RE-71R's.
Billy the TCS blinked while simply cruising. No slip. Just straight off throttle cruise. Went off on its own. I'll do more driving soon so i will report back. Also I've clearly gained 2 things: a better ride quality and less noise, and much needed ground clearance. The car sits higher because of the tires, and that little extra clearance makes a lot of difference. Also because the tire is larger in diameter, it reduces wheel gap both physically and visually by just having more meat on the sidewall. So you can raise the suspension a bit and that gets more clearance still. This ride/clearance thing has been a huge positive side effect.
Billy is right about the rotors. This is OEM versus 14.25" that I have no. No way will this fit under 17/18. The old rotor is about the size of my new hat.
Billy is right about the rotors. This is OEM versus 14.25" that I have no. No way will this fit under 17/18. The old rotor is about the size of my new hat.
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Keep me posted on the TCS. The PSS is an INCREDIBLE tire and one of the huge contributors to your great ride quality; that's why I love the tire. Great ride, little noise, and in the similar performance to the best street tires out there on track, which tend to be loud and ride rougher. The sidewall sizing also does not hurt your ride quality 
I just love the stance of your car and can't wait to get mine on! FYI - I could fit a set of CE28's over my 14" PFC brakes but there's literally 2mm of clearance and the inner diameter of the center barrel is too small to fit my brakes, so I do have a 17/18 setup that works but only a handful of wheels will clear from a spoke or barrel standpoint.
I just love the stance of your car and can't wait to get mine on! FYI - I could fit a set of CE28's over my 14" PFC brakes but there's literally 2mm of clearance and the inner diameter of the center barrel is too small to fit my brakes, so I do have a 17/18 setup that works but only a handful of wheels will clear from a spoke or barrel standpoint.
It seems like it would be hard to get a better R:F ratio for the '02+ than those sizes. Please do let us know if you can sort of the cause of the TCS light.
Billy when I asked why that rotor and not an even bigger one, since I had to go 18/19 anyway, they said the car is too light and won't build enough heat to get the ceramics to good operating temp. That make sense to you? because I have seen Ferraris that are near as light with larger rotors. How come it's fine there?
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Will do. Very soon.
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Will do. Very soon.
I too have the same goal in mind of setting up my NSX out to similar standards of a GT3 or Ferrari challenge with the ability to drive to and from the track with added Honda reliability. And also want the tires to last three 15 minute sessions and drive home. But that being said I may be ok running slightly slower times due to streetable tires to retain the current overall balance of the car, and if the fastest times possible is needed than would run a track set of R compound tires. trying to get the one set of tires to do both at the expense of all the other conditions we are discussing here does not seem feasible to me, but may make sense to others. that is what we will find out.
Billy, I'm more than willing to help and do minor adjustments to my wheel wheel well and covers to accommodate the larger wheels in order to be able to test fit the larger wheels you want to run, I may not agree in theory that the gain in traction for a N/A car without going to shorter gears will offset the set back in acceleration, but that does not mean I am unwilling nor reluctant to help you test and try your larger wheel goals. And I do fully agree there may a huge benefit for anyone running FI.
The timing is perfect for us to test this and were only 45 mins apart, we can easily test the different setups , once you put together the larger wheels and I put together a lighter than OEM setup, we can also find a third comparison, close to oem setup that a local may lend us. We can take my car out and compare the 3 variable setups with data logging and lap times sessions during any track day. And compare pros and cons to each set up like no one else has done yet on the NSX.
Regarding the out of proportion numbers comment....
I must admit an apology is due, and I went back and edited my numbers slightly since i was off by a tenth in the gear ratio calculations and had the decimal in wrong place on the inertia calculation, which reduced the overall potential effect of going from lightest/smaller strategy to largest/heaviest stradegy. the corrected 1/4 mile variance is .5 to .75 of a second from an incorrectly overestimated almost 1 second..
As far ad dyno hp and rolling inertia/weight related effects, I have seen wheel tire weight rwhp differences on a dyno and there are quite a few dyno comparisons online as well, a few i emailed you before, also the owner of the shop i use that has owned that dyno for 20years and has been building race cars for that long as well, he confirms it's like any other drive train part that causes hp loss. And according to his experience he is even more optimistic than my conservative calculations. If wheel/tire weight where not so relevant to performance there would be no point in so many companies efforts to produce light weight wheels and we would just run around on steel 25lbs steel wheels with the stickiest tires and call it a day. Miata spec racers know just changing to super light wheels or smaller diameter wheels with the same width/compound tires will affect lap times and passing speeds.
here are the few links for anyone else reading curious on the subject again to quite a few tests showing rwhp differences from wheel/tire weight. from 6 rwhp to 12rwhp
https://books.google.com/books?id=Y...gU#v=onepage&q=wheel weight dyno test&f=false
http://teamspeed.com/forums/aventad...ects-wheel-tire-weights-wheel-horsepower.html
http://www.corvetteforum.com/forums...s-rob-answers-inside-fresh-from-the-dyno.html
http://forums.nasioc.com/forums/showthread.php?t=2027575
http://www.superstreetonline.com/how-to/wheels-tires/0106tur-wheel-size-power/
I'm not expecting my numbers to be accurate, but to say it that 5lbs heavier wheels makes virtually no difference at all goes against the laws of physics, and just further takes this whole subject from everything i know. and here where not talking about 5 lbs where talking about closer to 10 lbs variable per wheel/tire
Again the only thing i may be completely missing here is exactly how much stickier these new tires are than what is available otherwise. I mean if they are really that much stickier to overcome all the traditional practices like i stated before, sign me up.
I am not looking to over think this any further and I appreciate you taking the time to fully explain everything you have, the next step would be testing the two options, which I am fully willing to help happen and would be happy to find out the results whether they make sense to me or not.
I may have exceeded the extent of my understanding or contribution of the topic and am looking forward to testing the real world results.
Billy, I'm more than willing to help and do minor adjustments to my wheel wheel well and covers to accommodate the larger wheels in order to be able to test fit the larger wheels you want to run, I may not agree in theory that the gain in traction for a N/A car without going to shorter gears will offset the set back in acceleration, but that does not mean I am unwilling nor reluctant to help you test and try your larger wheel goals. And I do fully agree there may a huge benefit for anyone running FI.
The timing is perfect for us to test this and were only 45 mins apart, we can easily test the different setups , once you put together the larger wheels and I put together a lighter than OEM setup, we can also find a third comparison, close to oem setup that a local may lend us. We can take my car out and compare the 3 variable setups with data logging and lap times sessions during any track day. And compare pros and cons to each set up like no one else has done yet on the NSX.
Regarding the out of proportion numbers comment....
I must admit an apology is due, and I went back and edited my numbers slightly since i was off by a tenth in the gear ratio calculations and had the decimal in wrong place on the inertia calculation, which reduced the overall potential effect of going from lightest/smaller strategy to largest/heaviest stradegy. the corrected 1/4 mile variance is .5 to .75 of a second from an incorrectly overestimated almost 1 second..
As far ad dyno hp and rolling inertia/weight related effects, I have seen wheel tire weight rwhp differences on a dyno and there are quite a few dyno comparisons online as well, a few i emailed you before, also the owner of the shop i use that has owned that dyno for 20years and has been building race cars for that long as well, he confirms it's like any other drive train part that causes hp loss. And according to his experience he is even more optimistic than my conservative calculations. If wheel/tire weight where not so relevant to performance there would be no point in so many companies efforts to produce light weight wheels and we would just run around on steel 25lbs steel wheels with the stickiest tires and call it a day. Miata spec racers know just changing to super light wheels or smaller diameter wheels with the same width/compound tires will affect lap times and passing speeds.
here are the few links for anyone else reading curious on the subject again to quite a few tests showing rwhp differences from wheel/tire weight. from 6 rwhp to 12rwhp
https://books.google.com/books?id=Y...gU#v=onepage&q=wheel weight dyno test&f=false
http://teamspeed.com/forums/aventad...ects-wheel-tire-weights-wheel-horsepower.html
http://www.corvetteforum.com/forums...s-rob-answers-inside-fresh-from-the-dyno.html
http://forums.nasioc.com/forums/showthread.php?t=2027575
http://www.superstreetonline.com/how-to/wheels-tires/0106tur-wheel-size-power/
I'm not expecting my numbers to be accurate, but to say it that 5lbs heavier wheels makes virtually no difference at all goes against the laws of physics, and just further takes this whole subject from everything i know. and here where not talking about 5 lbs where talking about closer to 10 lbs variable per wheel/tire
Again the only thing i may be completely missing here is exactly how much stickier these new tires are than what is available otherwise. I mean if they are really that much stickier to overcome all the traditional practices like i stated before, sign me up.
I am not looking to over think this any further and I appreciate you taking the time to fully explain everything you have, the next step would be testing the two options, which I am fully willing to help happen and would be happy to find out the results whether they make sense to me or not.
I may have exceeded the extent of my understanding or contribution of the topic and am looking forward to testing the real world results.
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Let me say something if we are going to talk about wheel and tire weights. 18/19 is not necessarily heavier than 17/18 and can even be lighter. As Billy has pointed out, the michelin pilot super sport is an outstanding tire. What he didnt mention is that it's also a very light tire. First of all, tires are generally heavier than wheels. Most tires carry most of their weight in the sidewall. That part actually contains a lot of metal by a wire mesh. The rubber itself is heavy. As you move outward from the wheel center, the weight has a much bigger effect because of inertia. You can easily make a wheel in 18/19 be lighter than a more typical 17/18. One of the other benefits of going 18/19 and opening up the tire selection is that you can actually get some really lightweight tires. And you select a wheel tire combo carefully and suddenly you are LIGHTER than your old 17/18 setup. There is as much as a 6 pound difference in between some tires just based on type and brand. Everyone always talks about wheel weight, no one talks about tire weight, and it's the more important thing on a rotating mass.
In any event... Unless you really are a driver of Billy's caliber I honestly don't think it matters much. Taking one turn on the track better will more than makeup for your extra wheel weight even if there was one. I save weight as a hobby more than think my its making me fast. I do it for fun. Makes me feel good. LOL
In any event... Unless you really are a driver of Billy's caliber I honestly don't think it matters much. Taking one turn on the track better will more than makeup for your extra wheel weight even if there was one. I save weight as a hobby more than think my its making me fast. I do it for fun. Makes me feel good. LOL
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The PSS is about 2 lbs lighter than comparable tires IIRC. FWIW I can easily feel when a wheel is 2 lbs lighter because I have gone through so many wheel setups. Of all my wheels, my tecnomagnesios are by far the lightest combination and every time I put them on driving dynamics are noticeably improved (acceleration, suspension reactions, etc). I actually started using 2lbs as my benchmark for weight differences when looking at wheels and that was also the major reason I went with AD08R over the star spec ZII everyone else gets.
There are others. The continental contiforce contact in a 305/30/19 was lighter than my 275/35/EGHITEEN NT01 by several pounds. Not available in 17/18 sizing. I was consistently able to make up for the slight increase in wheel weight with lighter tires. As far as I'm concerned, the old established prime notion that 18/19 is a performance compromise over 17/18 is no longer valid. Yes... If you must keep your front fender liners and trying to fit Yokohama S drives, it's a compromise. Once you remove that liner and rubbercoat the fenders, and go to a 225/40/18 which we've proven now works, you are taking about a superior performance setup in every category: ride, cost of tire, ground clearance, thermal capacity, large rotor clearance, even looks and overall weight. It's a small compromise to remove those liners and put them in your garage for all you gain.
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Billy's posting of this thread collided with my need for 18" front wheels timing-wise to clear carbon ceramic brakes. Was a huge help. And I wholehertedky believe in the philosophy he is describing, creating a "GT-3-like" NSX. Track and road on the car as is. This is a fantastic goal to have. Glad to have someone as knowledgable as he helping with all of this.
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Billy's posting of this thread collided with my need for 18" front wheels timing-wise to clear carbon ceramic brakes. Was a huge help. And I wholehertedky believe in the philosophy he is describing, creating a "GT-3-like" NSX. Track and road on the car as is. This is a fantastic goal to have. Glad to have someone as knowledgable as he helping with all of this.
I was watching this video and realized it may apply to this thread since we are talking about larger tires. It seems TCS is usually considered and touched on but does anyone know how this would affect the LSD? The 3% max variance recommended from stock OD is also the same I have seen on tire size calculators like the one at 1010tires.com. I would hate for people to try this and the same thing that happened to the Murci owners' LSDs happens a few months down the road to NSXs. Just a cautious thought... someone probably knows the answer.
https://youtu.be/UOMNFb8kOIU?t=10m57s
https://youtu.be/UOMNFb8kOIU?t=10m57s
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Turbo, technically a higher ride height isn't good for handling. But again, a better tire can offset the losses from a higher ride height. I would take a 0.5" increase nd a wheel weight penalty with a PSS over a lower S.Drive.
Nero, the sizes I mentioned in this thread are within the front to rear tolerances that the NSX has used in its factory sizes throughout the years (15/16 16/17 17/17). I posted a few times of various front to read 18/19 tire options that are within, close to, and out of the factory ranges.
Nero, the sizes I mentioned in this thread are within the front to rear tolerances that the NSX has used in its factory sizes throughout the years (15/16 16/17 17/17). I posted a few times of various front to read 18/19 tire options that are within, close to, and out of the factory ranges.
No of course... I realize the slight increased ride height is bad but the positive is the ground clearance without increased ugly wheel gap. That was something I never thought about until I changed... I was suddenly clearing more things.
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