Another newb question, apologies in advance guys. So I have signed up for the intro Trackmasters HPDE course and in the materials it tells us we should put an additional 4 pounds of pressure in each tire. I am running OEM tires and I believe the owners manual says that you do not need to adjust the tire pressure for high speed driving (I will confirm this). I would also think that the heat generated during driving on the track will also add to the tire pressure, so if anything, increasing the cold pressure seems to be the exact wrong thing to do? The only reason I can think of is to increase the strength of the sidewall during cornering, but with the other compromises and conflicting information detailed above. What am I missing and what do others do?
Overinflating Tires?
- Thread starter Liquid
- Start date
I run the stock recomended presures which for my 91 with stock tires is 35 and 41. You can't go wrong with that.
I agree with your point(s). Old crappy cars have tall side walls and will likely corner better with more air pressure to keep the tires upright. Our cars don't need more air pressure for this reason.
And heat adds a bunch of pressure. I start my R tires at 28psi or so and they heat up and pressure up (PV=nRT) to a more desirable 36psi.
If this is your very first track event, then you will likely not slide your tires as much as an aggressive and experienced driver will so yours won't heat up as much. So you might start 2 or 4 psi low.
Take an air pressure gague with you and make sure the heat doesn't take you up too high. You could even start as-is, then check when you get off the track each time and lower them to OEM.
Caveat: I really never do track events with the OEM tires so others with more experience with them on the track may have a more valuable opinion.
And heat adds a bunch of pressure. I start my R tires at 28psi or so and they heat up and pressure up (PV=nRT) to a more desirable 36psi.
If this is your very first track event, then you will likely not slide your tires as much as an aggressive and experienced driver will so yours won't heat up as much. So you might start 2 or 4 psi low.
Take an air pressure gague with you and make sure the heat doesn't take you up too high. You could even start as-is, then check when you get off the track each time and lower them to OEM.
Caveat: I really never do track events with the OEM tires so others with more experience with them on the track may have a more valuable opinion.
The pressures recommended by Acura are 33 psi front, 40 psi rear, measured cold (i.e. measured when the car has been sitting out of the sun, at the same ambient temperature at which the car will be driven).
I have done many track events using the stock tires, and I have found that those pressures work just fine on the racetrack.
I assume that they are saying that the recommended pressure is good for track use. But, if you start there, the track use will heat your tires up to too much pressure. You'll likely need to lower the pressure after the first few sessions to keep it at the recommended pressure.
IOW bring a tire pressure gauge and check after each session. Other participants will consider you more prepared.
IOW bring a tire pressure gauge and check after each session. Other participants will consider you more prepared.
I assume that they are saying that the recommended pressure is good for track use. But, if you start there, the track use will heat your tires up to too much pressure. You'll likely need to lower the pressure after the first few sessions to keep it at the recommended pressure.
IOW bring a tire pressure gauge and check after each session. Other participants will consider you more prepared.
agree plus most of the school hpde tips are ancient documents where that advice was ok for the tires of yesteryear.:wink:
This is exactly what I was thinking, and completely opposite of what is being recommended. Thanks.
OEM tires over their recommended range (33/40) when HOT (not cold) will become slippery especially if they have still good tread on them. Been there and done that for many track events ......
If you are a totally novice at the track, I suggest you start with about 2 psi lower (31/38) when cold and then after the first session check them - you will probably have reached 33/40 or even a bit higher. If you are able to carry speed, have many corners, and push the car a bit you will see about 5-6 psi increase assuming the ambient temp outside is not below 60F. I have seen up to 10+ psi increase in the rears when I pushed new OEM tires. But there is a point below which you do not want to deflate the tires heat or no heat - that is when you transition to R compound :wink:
HTH/YMMV.
If you are a totally novice at the track, I suggest you start with about 2 psi lower (31/38) when cold and then after the first session check them - you will probably have reached 33/40 or even a bit higher. If you are able to carry speed, have many corners, and push the car a bit you will see about 5-6 psi increase assuming the ambient temp outside is not below 60F. I have seen up to 10+ psi increase in the rears when I pushed new OEM tires. But there is a point below which you do not want to deflate the tires heat or no heat - that is when you transition to R compound :wink:
HTH/YMMV.
Not true. You are making the false assumption that the recommended pressures are 33F/40R measured hot. The actual recommended pressures are 33F/40R measured cold.
That's for street tires. If you are using R compound track tires, you can probably find the tire manufacturer's recommendation for hot pressures, either on their website or on the Tire Rack's website.
On the street you will not heat up you tires much. Yes the cold pressure takes that into account. On the track you will be doing allot of hard cornering, hard breaking. You don't drive that hard on the street.
Think about it...
For a first day driver unless I notice the tires getting greasy I usually don't tell them to check there tires. If they are doing well I'll mention it.
2lbs cold is not much.
In California where track temps are 70+ drop a few pounds. If the ambient temp is 30 doesn't matter?
I use Michelin Pilot Sport Cup's.
I set my tires at 22psi cold front and back. Once hot they are 33ft 36rear where I want them. I'm not slow..
I check to keep them at 30 front /33 rear while on the track. I can feel the difference when the temp in the rear goes up, oversteer. Falken Azinis.
Never set them higher.
Lance
Never set them higher.
Lance
Exactly.
I've using 32/35 for Kumho stock 15/16 and it felt fabulous.
36/38 for R compounds is what I felt comfortable with...
My suggestion: You probably have to drive for awhile to the track, once you got there, adjust the pressure at 35/38. Start your first session that way; If it's your first time, you probably will have 2-3 psi increase or even less. Then re-adjust to your liking.
36/38 for R compounds is what I felt comfortable with...
My suggestion: You probably have to drive for awhile to the track, once you got there, adjust the pressure at 35/38. Start your first session that way; If it's your first time, you probably will have 2-3 psi increase or even less. Then re-adjust to your liking.
I am very much a track noob (2 events at Mid Ohio), but I learned a lesson 2 days ago at mid ohio. The first session, my tires were over inflated. I think I had 50 rear 40 front hot. Lucky for me it was wet and our first session in the lowest group (D). I noticed my back end was a little loose in some turns. I was very concerned because I was not even drving the car very hard. I got back to the garage and saw my high pressures mentioned above. I lowered them about 5 pounds each and the car was great. For my novice skills, the factory settings are perfect.
This Tire Rack web page has links to specific recommendations for the following R compound tires:
Care and Feeding of the BFGoodrich g-Force R1
Care and Feeding of the Hoosier A6/R6
Care and Feeding of the Kumho ECSTA V700
Care and Feeding of the Kumho ECSTA V710
Care and Feeding of the Kumho V700 Victoracer
Care and Feeding of the Michelin Pilot Sport Cup
Care and Feeding of the Pirelli P Zero Corsa
For Toyo's recommendations, click here for the RA-1, and here for the R888 (both say high 30's to low 40's hot).
That's very close to Michelin's recommended 32F/36R hot.
As you can see, optimal hot pressures can vary considerably, depending on the tire.
It depends on what your trying to accomplish.
3 lap flyer, 30 minute session, 3 hour endurance race?
It also depends on your setup, tire, wheel, and expected running time.
mid to high 30's hot are a good generalization/starting point. Optimal pressures also depend on your tire temps (buy a pyrometer if you're going to be tracking a lot -probe type!!!!) and what temp range and spread your tires want.
To stir up the pot: FYI - some time attack cars are running high 20's hot on Toyos :wink:
-Don't do this unless you know what you're doing.
3 lap flyer, 30 minute session, 3 hour endurance race?
It also depends on your setup, tire, wheel, and expected running time.
mid to high 30's hot are a good generalization/starting point. Optimal pressures also depend on your tire temps (buy a pyrometer if you're going to be tracking a lot -probe type!!!!) and what temp range and spread your tires want.
To stir up the pot: FYI - some time attack cars are running high 20's hot on Toyos :wink:
-Don't do this unless you know what you're doing.
I'm curious as to what your theory is as to why 20's hot on ra1's would be advantageous in a time trial?
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