Cold Tire pressure
04-13-2006, 03:07 PM
#3
Nordschleife Master
Road course, I assume?
It's much better to start too low and work up than too hard and work down. The tires will heat a lot and pressures can go up unexpectedly.
Start at 30psi front/back and then adjust them to higher pressure if the wheels stick well at _the end_ of a session and steering too vague. Down if the tires are getting loose as the session goes on.
And the optimal pressure depends too much on driving style, car weight, ambient temp, surface temp, surface material, alignment and so on for anyone to give you the numbers that are right for you. Someone who has run the same tires on the same track would be a good one to ask.
It's much better to start too low and work up than too hard and work down. The tires will heat a lot and pressures can go up unexpectedly.
Start at 30psi front/back and then adjust them to higher pressure if the wheels stick well at _the end_ of a session and steering too vague. Down if the tires are getting loose as the session goes on.
And the optimal pressure depends too much on driving style, car weight, ambient temp, surface temp, surface material, alignment and so on for anyone to give you the numbers that are right for you. Someone who has run the same tires on the same track would be a good one to ask.
04-13-2006, 03:46 PM
#4
Nerd Herder
Rennlist Member
Rennlist Member
Originally Posted by GlenL
Road course, I assume?
It's much better to start too low and work up than too hard and work down. The tires will heat a lot and pressures can go up unexpectedly.
Start at 30psi front/back and then adjust them to higher pressure if the wheels stick well at _the end_ of a session and steering too vague. Down if the tires are getting loose as the session goes on.
And the optimal pressure depends too much on driving style, car weight, ambient temp, surface temp, surface material, alignment and so on for anyone to give you the numbers that are right for you. Someone who has run the same tires on the same track would be a good one to ask.
It's much better to start too low and work up than too hard and work down. The tires will heat a lot and pressures can go up unexpectedly.
Start at 30psi front/back and then adjust them to higher pressure if the wheels stick well at _the end_ of a session and steering too vague. Down if the tires are getting loose as the session goes on.
And the optimal pressure depends too much on driving style, car weight, ambient temp, surface temp, surface material, alignment and so on for anyone to give you the numbers that are right for you. Someone who has run the same tires on the same track would be a good one to ask.
04-13-2006, 03:50 PM
#5
Race Director
Dan: are you going to Pocono with Metro, or Lime Rock with NNJR? (I'll be at Lime Rock with NNJR this weekend)
What kind of tires are you running?
With street tires, I'd go 2-3 psi higher (COLD pressure) than what you are using on the street. Adjust up or down based on how the car feels. Higher pressure will make for a slightly stiffer sidewall and increase your turn-in ability. But be careful not to exceed the recommended high pressures.
If you have R-compounds, then the answer is it depends on what the optimal hot pressures are, and how much the pressure increases from COLD to HOT pressue. In my case, with the Toyo Proxes RA-1's, my HOT pressure goal is 40psi at all four corners. On cold days, I start @ 36psi cold, and on hot days, I start around 33 psi. I run 245-45/16 size tires at all four corners - part of the reason why I aim for the same temps at all four corners.
Hope this helps,
-Z-man.
What kind of tires are you running?
With street tires, I'd go 2-3 psi higher (COLD pressure) than what you are using on the street. Adjust up or down based on how the car feels. Higher pressure will make for a slightly stiffer sidewall and increase your turn-in ability. But be careful not to exceed the recommended high pressures.
If you have R-compounds, then the answer is it depends on what the optimal hot pressures are, and how much the pressure increases from COLD to HOT pressue. In my case, with the Toyo Proxes RA-1's, my HOT pressure goal is 40psi at all four corners. On cold days, I start @ 36psi cold, and on hot days, I start around 33 psi. I run 245-45/16 size tires at all four corners - part of the reason why I aim for the same temps at all four corners.
Hope this helps,
-Z-man.
04-13-2006, 03:54 PM
#6
Rennlist Member
i run victoracers and usually start around 35psi on each corner, get a feel for what i need- more understeer, more oversteer- and drop pressures from there after they start warming up. I would be afraid of starting off at 30psi and then wrecking or not getting pressures up enough and having to find an air hose, of course if you have an air tank that changes things. I like to keep my pressures consistant throughout the day from 34-37psi making small adjustments front or rear at a time to get the car setup for that track.
04-13-2006, 04:52 PM
#7
Race Car
Thread Starter
Originally Posted by Z-man
Dan: are you going to Pocono with Metro, or Lime Rock with NNJR? (I'll be at Lime Rock with NNJR this weekend)
What kind of tires are you running?
With street tires, I'd go 2-3 psi higher (COLD pressure) than what you are using on the street. Adjust up or down based on how the car feels. Higher pressure will make for a slightly stiffer sidewall and increase your turn-in ability. But be careful not to exceed the recommended high pressures.
If you have R-compounds, then the answer is it depends on what the optimal hot pressures are, and how much the pressure increases from COLD to HOT pressue. In my case, with the Toyo Proxes RA-1's, my HOT pressure goal is 40psi at all four corners. On cold days, I start @ 36psi cold, and on hot days, I start around 33 psi. I run 245-45/16 size tires at all four corners - part of the reason why I aim for the same temps at all four corners.
Hope this helps,
-Z-man.
What kind of tires are you running?
With street tires, I'd go 2-3 psi higher (COLD pressure) than what you are using on the street. Adjust up or down based on how the car feels. Higher pressure will make for a slightly stiffer sidewall and increase your turn-in ability. But be careful not to exceed the recommended high pressures.
If you have R-compounds, then the answer is it depends on what the optimal hot pressures are, and how much the pressure increases from COLD to HOT pressue. In my case, with the Toyo Proxes RA-1's, my HOT pressure goal is 40psi at all four corners. On cold days, I start @ 36psi cold, and on hot days, I start around 33 psi. I run 245-45/16 size tires at all four corners - part of the reason why I aim for the same temps at all four corners.
Hope this helps,
-Z-man.
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04-13-2006, 05:43 PM
#8
Race Director
Originally Posted by jeeper31
Z- Going to poconos with Metro (hopefully, car still in shop). I am running Fuzion ZR1 tires.
Check the tire after the runs for rollover- you should be able to see how far down the sidewall the tire is being scrubbed. Ideally, you want to be using most of the tire tread. If you're not using it all, then the tire is over-inflated. If you are getting scrub marks further down from the tread on onto the sidewall, then your tire is under-inflated.
-Z.
