R compounds make steering wheel vibrate?

[bambookid]

For Autox and tracks sessions, I just picked up a set of OEM rims 91's that came with Khumo Ecsta V710's. The previous owner only tracked them once in 2009. Since then they've been sitting in his garage.

After mounting them on the NSX and driving on local roads, I felt alot of shuttering and vibration on the steering wheel. I had the tires dismounted and rebalanced and the same problem persists. I remounted my street rims with Dunlop Direzza Z1's and the car is as smooth as butter!

Is this normal for R compounds? or perhaps these are crappy R compounds? or perhaps they're this set is too old?

Thanks for your help
Ed

 

[W]

This is not normal. Take them back to your wheel and tire guy and he should be able to figure out the source.

 

[stuntman]

Not normal, maybe the wheels are still out of balance and or the carcass of the tire deflected and has a flat spot if the tires weren't sitting on their sides when they were stored.

 

[EK@ASU]

How long were the tires sitting? And where? As far as I know soft tires like those shouldn't be stored anywhere to hot or cold.

 

[docjohn]

for all my years of driving to and from track events on RA1's vibrations had the same causes as street tire/wheel combos.The track brings about a few more causes not usual to street tires,,chunks of old rubber inside the wheel,wheel weights coming undone,bent rims from hitting hard stuff,and warped to hell brakes:frown:

 

[bambookid]

Thanks everyone for the helpful input. I'm gonna get rid of these and do it properly and get a new set. Any recommendation and tire sizes for OEM 91 rims sizes? My car has H&R Lowering springs making the car 1.25 inches lower.

Thanks,
Ed C.

 

[W]

I think you'll have no issues running the 225/50/15 in the front. Just make sure you know what the source of the issue is. If it's the wheel, you'll be buying tires for no reason.

 

[Tamar]

Thanks everyone for the helpful input. I'm gonna get rid of these and do it properly and get a new set. Any recommendation and tire sizes for OEM 91 rims sizes? My car has H&R Lowering springs making the car 1.25 inches lower.

Thanks,
Ed C.

If you are running R compounds on the OEM wheels the maximum tire size you can run is 205/50-15 front and 225/50-16 rear, the rims just aren't wide enough for bigger tires......that said you'll be amazed how much grip you have once you get them hot.
I have had the same balance problem as you, I think the tires go flat on the bottom if you leave the car sitting for a while and vibrate. I use balancing beads now and don't have a problem.

 

[nsxtasy]

If you are running R compounds on the OEM wheels the maximum tire size you can run is 205/50-15 front and 225/50-16 rear, the rims just aren't wide enough for bigger tires......that said you'll be amazed how much grip you have once you get them hot.

Yup. That's what I'm using, the stock sizes. The good news is, most of the R compounds on the market are available in those sizes. The other good news is, you can fit the track tires inside the car and drive to the track on your street tires.

I think the tires go flat on the bottom if you leave the car sitting for a while and vibrate. I use balancing beads now and don't have a problem.

I've never had a vibration problem from the car sitting. I mean, they vibrate, but only for about the first few blocks I drive after the winter, and then it goes away. I don't think this is your problem.

What are "balancing beads"?

 

[Tamar]

Yup. That's what I'm using, the stock sizes. The good news is, most of the R compounds on the market are available in those sizes. The other good news is, you can fit the track tires inside the car and drive to the track on your street tires.

Yes, and they are cheap!

What are "balancing beads?

Balancing beads are little glass (I think) beads that are poured in when you are installing the tire (about 3 oz. each tire), I don't know exactly how it works but somehow centrifugal force throws them to the lightest side of the tire, if the tire wears unevenly it automaticly rebalances, works like a charm, I use them in the NSX an both my bikes...I think the idea comes from the trucking industry.

 

[W]

Thanks everyone for the helpful input. I'm gonna get rid of these and do it properly and get a new set. Any recommendation and tire sizes for OEM 91 rims sizes? My car has H&R Lowering springs making the car 1.25 inches lower.

Thanks,
Ed C.

What were the tire sizes on the current set of wheels?

If you're going to track the new tires, what brand and model are you thinking? V710's? They're not going to last an awful long time on the track especially if you run narrow widths. Have you considered a more durable and less sticky tire, such as an RA1?

If you were just going to autocross on V710's with no track days, I'd say use 225 front and 265 rear. The 265 is just out of spec for the 8" rears but that should be fine in autocross situations. For autocross and track, I guess you could use 205 front and 245 rear.

 

[bambookid]

W, i'm running 225 50 15's (Front) & 265 45 16's (rear).

The whole point of getting OEM with R compounds was to reduce weight from my street set up. I weighed them and this is what I came up with...

Street Set Up.
Rims: Volk AV3 (aka. boat anchors).
Front: 215 40 17. w Dunlop Z1. 45 lbs.
Rears: 275 35 18. w Dunlop Z1. 57 lbs.

Track Set Up
Rims: OEM 91
Front: 225 50 15. w Khumo V710. 37 lbs.
Rear: 265 45 16. w Khumo V710. 44 lbs.

Plus, if the OEM get dinged up I don't care.

Tamar, i'm also considering your option to go with OEM width. That way I can fit them in the NSX and swap them at the track...

hmmmm.... decisions decisions. You guys are very helpful! Thanks!

 

[bambookid]

BTW, last year, i tracked my street set with Dunlop Z1 at Laguna Seca and thought they were great! Had a blast! I've never run R compounds and therefore decided to look for a set of OEM's.

1 month later I got the OEM's with Khumo's. In order to test them, i went to AutoX. I drove from my home to the AutoX on the OEM's, which was 30 miles away, and that was when I discovered the vibrating between 40-70mph. For some reason over 85mph the V710's got smooth.

Anyhow, after the AutoX, i wasn't that impressed with R compounds. I believe it was for 2 reasons.

1) The AutoX never allowed the tires to get hot.
2) The parking lot had more gravel/crap and thus the car was kinda slippery.

My question is, are R Compounds really worth it!!! I believe the answer is YES but i guess I wanted to get your input.

Thanks for reading,
Ed C.

 

[W]

The V710 is one of the top autocross Dot r-compound tires. I don't know the exact history of your previous V710's, how many heat cycles for real, how they were used, how they were stored, how old they are, and when they were first put into service. If you try to stick your finger nail into the V710's and then your Star Specs, how do they compare? The V710 should be noticeably softer. If not, then they may have more heat cycles or are older or were used differently than you think, but as you mentioned the lot may have come into play. Another thing to note, the V710's work well with lots of slip angle, much more than the Star Specs so that may be something you need to get used to. One last thing, V710's are fast right from the start, much faster than a regular street tire or regular track tires. If they're heat cycled out, they will be slippery the first run but will gradually get faster as they heat up until the are pretty grippy.

You may not notice so much going to r-compounds, but once you really get used to them you sure will notice going back to street tires.

Are r-compounds worth it? It's a personal decision. I think they are.

 

[nsxtasy]

Anyhow, after the AutoX, i wasn't that impressed with R compounds. I believe it was for 2 reasons.

1) The AutoX never allowed the tires to get hot.
2) The parking lot had more gravel/crap and thus the car was kinda slippery.

My question is, are R Compounds really worth it!!! I believe the answer is YES but i guess I wanted to get your input.

You may not notice so much going to r-compounds, but once you really get used to them you sure will notice going back to street tires.

Are r-compounds worth it? It's a personal decision. I think they are.

If you are getting R compounds for autocross use, you're better off getting a tire made specifically for autocross, such as the Hoosier A6. It's designed with a sticky compound that doesn't need to be warmed up to grip the way racetrack tires (most other R compounds) do. Most R compounds need a good hot lap or so before they start really gripping well. I learned this lesson when I went off the track at turn 3 on Road America on my out-lap, before the tires had a chance to warm up!

As for the difference between R compounds and sticky street tires, here's my experience. I used the OEM tires on the track for nine years before I switched to R compounds. The first time I used the R comps, I didn't notice any difference in grip! However, that was because I was still driving the way I was with the street tire, expecting the same amount of grip. As I became more familiar with the limits of the R comps, I started driving faster, through the corners, later braking, etc. Now, when I occasionally drive with street tires on the track, they seem unresponsive, because I'll turn in the way I would with the R comps and they aren't capable of as much grip through the turns. So yes, there's a big difference in grip, but you may not notice it when first moving up to R comps.

Are they worth it? That's up to you to decide. R comps cost more and wear faster, and they involve inconveniences like swapping tires, carrying them inside the car, replacing them more frequently, etc. You may be perfectly happy using street tires on the track or in autocross, as I was for nine years. Now, I use R compounds at almost every track event.