R888 set up advice from Toyo UK
Discussion
I received the following info as a response to an email I sent to Toyo. I was wanting advice on tyre pressures for the R888's on my Clio. This is straight from Toyo's Technical and Motorsport manager, so straight from the horses mouth.
Hope this is helpful to everyone.
Cheers
Michael
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
Hope this is helpful to everyone.
Cheers
Michael
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
Not wanting to nit pick but this is not totally correct
'As a tyre gets hotter the pressure increases, this is due to the moisture in the air.'
All gases expand with increase in temp thus pressures will rise, the fact air has moisture in it is irrelevant unless its saturated and the water turns to steam. Does the air in a tyre run above 100 degrees C?
'As a tyre gets hotter the pressure increases, this is due to the moisture in the air.'
All gases expand with increase in temp thus pressures will rise, the fact air has moisture in it is irrelevant unless its saturated and the water turns to steam. Does the air in a tyre run above 100 degrees C?
Mark in Ireland said:
Not wanting to nit pick but this is not totally correct
'As a tyre gets hotter the pressure increases, this is due to the moisture in the air.'
All gases expand with increase in temp thus pressures will rise, the fact air has moisture in it is irrelevant unless its saturated and the water turns to steam. Does the air in a tyre run above 100 degrees C?
'As a tyre gets hotter the pressure increases, this is due to the moisture in the air.'
All gases expand with increase in temp thus pressures will rise, the fact air has moisture in it is irrelevant unless its saturated and the water turns to steam. Does the air in a tyre run above 100 degrees C?
This is why race teams typically use nitrogen to fill tyres, as it has no moisture in it and is not as sensitive to heat changes as air, thus giving more stable pressures over a wider range of temperatures.thats not entirely true either.
The idea behinfd using nitrogen is that its a single element substance so the pressure increse per degree temperature rise is a known quantity.
Once you start mixing 'moisture' it screws up the known quantity part of it, the more 'moisture' there is the greater the deflection from the expected results
The idea behinfd using nitrogen is that its a single element substance so the pressure increse per degree temperature rise is a known quantity.
Once you start mixing 'moisture' it screws up the known quantity part of it, the more 'moisture' there is the greater the deflection from the expected results
Mark in Ireland said:
Not wanting to nit pick but this is not totally correct
'As a tyre gets hotter the pressure increases, this is due to the moisture in the air.'
All gases expand with increase in temp thus pressures will rise, the fact air has moisture in it is irrelevant unless its saturated and the water turns to steam. Does the air in a tyre run above 100 degrees C?
I think the Toyo explanation is certainly good enough. You are right that gasses used to inflate tyres will increase pressure as temperature increases, but probably complicating an otherwise very useful thread.'As a tyre gets hotter the pressure increases, this is due to the moisture in the air.'
All gases expand with increase in temp thus pressures will rise, the fact air has moisture in it is irrelevant unless its saturated and the water turns to steam. Does the air in a tyre run above 100 degrees C?
For what it's worth, the moisture in the tyre does not need to be at 100c to cause temperature instability. Air is around 78% nitrogen, and the remaining 22% is made up of other gasses which is where the moisture is introduced. This moisture has several disadvantages to being in the tyre, and one of those is a greater pressure instability when exposed to temperature change. It contributes to a greater change of pressure than you probably realise.
With nitrogen, it's a dry gas, so although the ideal gas law is still followed, the moisture does not compound the problem. You will still see pressure change with nitrogen, but less so since the moisture element is not present.
It's way beyond the scope of this thread, but since it was brought up I thought I'd add my 2p's worth.
I've found Alan Meaker very helpful in the past with advice on pressure settings for the R888. I've recently fitted a set of R1Rs to the car and again sent an email to Toyo. Within 15 minutes I had a reply from him.
Great product support.
Great product support.
Edited by Mound Dawg on Thursday 24th December 12:48
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