Track tyre pressures?

[abrussich 0]

I believe the owners manual lists tire pressures at 24 front 26 rear. What pressures are you serious track user types using?

Are you maintaining the factory recomendations or lowering the pressures on track days?

Al B.

[ads_green 12]

I find them pressures bang on really. The trick is maintaining them!

[[email protected] 0]

Al,

The 24 and 26 are cold pressures. They further suggest that you check after 5 laps for 28 lbs. Chances are, if the original setting was 24/26, the pressure after getting the tires up to temp will be over 30#'s. According to Nick Adams, the OEM tires go away very quickly at 30 and better lbs. of pressure. I've also found this the case which adds to the "tail happy" nature of the beast. There have been other threads on this forum dealing with tire pressures and it seems that those with the most experience are running hot at or near the Lotus 24/26 cold pressures. The best way is to experiment and use of a tire pyrometer to get the best pressures for your driving style and that required of the track.

Bill

[[email protected] 1]

28psi all round when hot works for me.

If using standard air, the rear pressures especially will go up quickly as the wheel heats up, so you need to check and adjust frequently (i.e. not just the once) until they stabilise.

One of the trackside tyre fitters kindly filled my tyres with nitrogen in the middle of the year and this dramatically reduced the pressure change with temperature.

[stephanie plum 1]

I run 1.6/1.8, (which I think equates to 24/26) when hot, however it is worth noting that Martin Donnelly recommends 23 all round when hot according to a post on another thread from ScottyC.

[pgn340r 22]

28psi all round when hot works for me.

If using standard air, the rear pressures especially will go up quickly as the wheel heats up, so you need to check and adjust frequently (i.e. not just the once) until they stabilise.

One of the trackside tyre fitters kindly filled my tyres with nitrogen in the middle of the year and this dramatically reduced the pressure change with temperature.

This only confirms my opinion, Del, you are a tart, special air indeed

[ads_green 12]

Al,

The 24 and 26 are cold pressures. They Bill

Thats what I run "hot". 30 is just WAY too much

I run 1.6/1.8, (which I think equates to 24/26) when hot, however it is worth noting that Martin Donnelly recommends 23 all round when hot according to a post on another thread from ScottyC.

ding

[Guest Norm]

Is there a consensus among 2-Eleven drivers on cold and hot pressures with R888's?

[MAXR 0]

Here is a letter taken from the VX220 Forum regarding Track day tyre pressures for R888's...

It's very useful!

................................................................................

.................................................................................

......................................................

My name is Alan Meaker, I am the Motorsport Manager for Toyo Tyres (UK) Ltd.

I was at Rockingham on the Saturday 1ST March at the LOT trackday and worked with a couple of cars using our R888 tyre regarding pressures and tread temperatures.

What I would like to do is to offer some advice on tyre temperatures and pressures and how to achieve the best from our tyres when taking part in either trackdays or racing.

The R888 has a semi race construction (very stiff) and a race tread compound. The optimum tread temperature range is between 85C and 95C measured using a probe type pyrometer, and ideally a maximum difference across the tread of 9C. The maximum hot pressure we recommend is 40psi. Camber angles up to 5 degrees are permissible but the final setting will depend on tread temperatures. It is advisable to have as much positive castor as practical as castor induces a beneficial camber change during cornering. I recommend that the tyres be put through 2 heat cycles before hard use.

The pressures you use will initially depend on the weight of the car, too little pressure on a heavy car can lead to over deflection of the tyre and subsequent failure.

Below are some basic settings:

VEHICLE WEIGHT COLD PRESSURE HOT PRESSURE

Very Light < 800kg 17 - 22 psi 22 - 29 psi

Light 800kg - 1000kg 20 - 26 psi 24 - 32 psi

Heavy 1000kg - 1400kg 23 - 27 psi 28 - 40 psi

Very Heavy > 1400kg 27 - 35 psi 37 - 40 psi

As a tyre gets hotter the pressure increases, this is due to the moisture in the air. The cold pressure you set to achieve a desired hot pressure will depend on the conditions on the day i.e. ambient and track temperature, wet or dry. If the day/track is cold you will need to start with a higher cold pressure as the tyre will not get as hot therefore the pressure increase will not be so great.

Hot pressures must be balanced side to side. Once the tyres have cooled you will find that you will have a difference in pressure side to side, if you have been racing on a right hand track you will find the offside pressures will usually be higher than the nearside.

Changing hot inflation pressures by small amounts can be used to fine tune handling.

Reduce Oversteer Reduce rear pressures or increase front pressures

Increase Oversteer Increase rear pressures or reduce front pressures

Reduce Understeer Reduce front pressures or increase rear pressures

Increase Understeer Increase front pressures or reduce rear pressures

Achieving the required tread temperatures will depend again on the conditions on the day i.e. ambient and track temperature, wet or dry.

You often here competitors saying

[Guest Norm]

Max,

Thanks. Terrific info. It coincides with what Jack had suggested to me (1-2 psi over AO48 pressures), which sounded reasonable until spec Miata drivers mentioned that they were using pressures consifderably higher than what they use with RA-1's. According to the bulletin, being so light, the 2-Eleven doesn't need as large an increase as the Miatas. Thanks again.

Norm

[Guest Jack]

Norm,

Every so often I get lucky and provide correct info -- glad I could be of some help.

All the best,

Edited June 15, 2009 by Jack