Clio 172 Track day tyre pressures. Help needed please
Discussion
We have a Clio 172 which we have used on 4 track days so far. We have now fitted R888s for dry use and T1R for wet, both 195/50 on 15" rims.
Can someone please suggest the optimum tyre pressures for track day use.
On a recent wet day at Bedford, we had very little grip with the T1R's set at 33psi F and 30 psi R. A very helpful Lotus owner suggested dropping this to 26F/24R which seemed very low. We dropped them to 28F/26R which seemed to help, but I was reluctant to go any lower.
I am hoping someone can recommend pressures for both tyres, and also variations required depending on weather/air temperature.
Many thanks
Mike
Can someone please suggest the optimum tyre pressures for track day use.
On a recent wet day at Bedford, we had very little grip with the T1R's set at 33psi F and 30 psi R. A very helpful Lotus owner suggested dropping this to 26F/24R which seemed very low. We dropped them to 28F/26R which seemed to help, but I was reluctant to go any lower.
I am hoping someone can recommend pressures for both tyres, and also variations required depending on weather/air temperature.
Many thanks
Mike
On 888's you want a hot pressure of anywhere between 26-28 front, 26-28 rear to start with and fine tune from there, but I never had any need I don't think. This is what I used to run on my 182 Trophy. On the T1R's, more like 30-31.
But I stress, these are hot pressure...get to the track, do a few laps, come in and check and change them immediately to these figures when they are very hot.
But I stress, these are hot pressure...get to the track, do a few laps, come in and check and change them immediately to these figures when they are very hot.
i done the same on my fiesta. If i run standard 32/26 pressures, its fine for 2-3 laps but it will peak at 46/42 causing grip to fall away very fast. Drop them to about 24/24 and they will feel bad for the first 2-3laps while i warm up, but will be much better when they do, and will be about 34/34 when full hot. Just gotta make sure you dont roll over on the sidewall too much, keep an eye on the wear.
Some info here on trackday pressures...
http://www.tvrmonster.com/tyrestrack.html
rwd, but the rules are the same...
http://www.tvrmonster.com/tyrestrack.html
rwd, but the rules are the same...
Thanks for your responses, they confirm our pressures will have been too high.
Our next day will be in January and we will have the benefit of lower pressures, and also new Pagid pads. That's if Santa delivers as requested! We were struggling at Bedford to stop for 2 of the tighter turns. Brake fade and a little Brain fade causing a couple of spins in the wet.
Cheers
Michael
Our next day will be in January and we will have the benefit of lower pressures, and also new Pagid pads. That's if Santa delivers as requested! We were struggling at Bedford to stop for 2 of the tighter turns. Brake fade and a little Brain fade causing a couple of spins in the wet.
Cheers
Michael
Just thought I'd post the reply to an email sent to Alan Meaker who is Toyo's Technical and Motorsport Manager. I also have attached the info sheet he sent.
I will also post these on the forum for anyone else to see.
Hi Michael,
I am going to guess your cars weighs around 950kg, this being the case I would suggest a hot pressure of 30psi (24psi cold) as a good starting point.
I have attached some information that should help.
If you would like to discuss further please give me a call from Monday on.
Kind Regards
Alan
Alan Meaker
Technical and Motorsport Manager
Toyo Tyre UK
SET UP ADVICE FOR THE TOYO PROXES R888
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 a heat cycle before hard use, this will scrub them in and remove any mold release agent.
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 “My tyres started to go of towards the end of the race”, this is usually due to the tread getting to hot.
The tread temperatures are constantly changing through out a race, hotter when cornering and cooler when on the straights and cooling even more when you are slowing to come into the pits. Therefore the temps you record in the pits will be lower than those during the race. So if you record temperatures within the range given above the probability is the temps will be too high during the race.
Increasing your tyre pressures will cause your tread temperatures to increase, more pressure stiffens the tyre’s casing which results in the tread having to do more work resulting in the tread getting hotter. Lowering your pressures will cause them to decrease.
Inevitably changing one thing will affect other things, the whole set up of your car is a compromise between anything that is adjustable.
Alan Meaker
Technical and Motorsport Manager Toyo Tyres (UK) Ltd
I will also post these on the forum for anyone else to see.
Hi Michael,
I am going to guess your cars weighs around 950kg, this being the case I would suggest a hot pressure of 30psi (24psi cold) as a good starting point.
I have attached some information that should help.
If you would like to discuss further please give me a call from Monday on.
Kind Regards
Alan
Alan Meaker
Technical and Motorsport Manager
Toyo Tyre UK
SET UP ADVICE FOR THE TOYO PROXES R888
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 a heat cycle before hard use, this will scrub them in and remove any mold release agent.
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 “My tyres started to go of towards the end of the race”, this is usually due to the tread getting to hot.
The tread temperatures are constantly changing through out a race, hotter when cornering and cooler when on the straights and cooling even more when you are slowing to come into the pits. Therefore the temps you record in the pits will be lower than those during the race. So if you record temperatures within the range given above the probability is the temps will be too high during the race.
Increasing your tyre pressures will cause your tread temperatures to increase, more pressure stiffens the tyre’s casing which results in the tread having to do more work resulting in the tread getting hotter. Lowering your pressures will cause them to decrease.
Inevitably changing one thing will affect other things, the whole set up of your car is a compromise between anything that is adjustable.
Alan Meaker
Technical and Motorsport Manager Toyo Tyres (UK) Ltd
Ignoring the weight issue....
The R26R on R888 for example is stickered to run IIRC F34 and R30 on road.
For track and race they say change to F30 and R34.
The reason being the increasing heat on the fronts at the track, so you need a lower cold starting pressure.
And the rears - almost lifting the rear inner wheel means a lot more load on the outer rear, hence the increase in pressure.
So maybe try reversing the oem pressures at the track, F&R, like the R26R manual suggests?
The R26R on R888 for example is stickered to run IIRC F34 and R30 on road.
For track and race they say change to F30 and R34.
The reason being the increasing heat on the fronts at the track, so you need a lower cold starting pressure.
And the rears - almost lifting the rear inner wheel means a lot more load on the outer rear, hence the increase in pressure.
So maybe try reversing the oem pressures at the track, F&R, like the R26R manual suggests?
Edited by m1bjr on Wednesday 23 December 23:25
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