what tyre pressure on track - 325 with 888's
Moderator: martauto
WTF? pressure science is all about getting optimum tyre temperatures, its got nothing to do with stiffness. Pressures are irrelevant as long as they're not stupidly low and cause punctures when taking the curbs.Mox3d wrote:
1lb tyre pressure + 50lb spring rate rule of thumb.
no i am even more confused...what do pressures do you start out with on a track day? I set all my tyres to 27 at bedford ad. The rears look fine, the fronts look a bit 'rubbed' with raised rolled edges, if you know what i mean.
Really just going over the ground as stated above, but the info below is 'from the horses mouth' i.e. Toyo's competition department.
They state:
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.
Easy, isn't it?
Kim.
edit for some reason the table of pressures gets all mixed up but if you look carefully you can still make sense of what'a what!
They state:
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.
Easy, isn't it?
Kim.
edit for some reason the table of pressures gets all mixed up but if you look carefully you can still make sense of what'a what!
Someone on here told me to run mine at 27psi hot, which was about 21/22 cold. They worked well and wore well too.
Start at 22 cold, do a session, then check them straightaway and get them to 27 hot. Job done.
Start at 22 cold, do a session, then check them straightaway and get them to 27 hot. Job done.
-
JimmyC
- E30 Zone Squatter
- Posts: 1537
- Joined: Tue Jun 21, 2005 11:00 pm
- Location: Southend ESSEX
- Contact:
Toyo recommend a hot pressure of 30psi
To get to that in a stripped car- you will be somewhere between 22psi- 25psi when cold, the range will depend on conditions, the circuit, the car, your driving style etc etc etc
I tend to go out at in a pbmw 320 with around 24psi, which I think is pretty much the norm across the paddock
Thats on a 195/50/15 will check the compound as cant remember it
To get to that in a stripped car- you will be somewhere between 22psi- 25psi when cold, the range will depend on conditions, the circuit, the car, your driving style etc etc etc
I tend to go out at in a pbmw 320 with around 24psi, which I think is pretty much the norm across the paddock
Thats on a 195/50/15 will check the compound as cant remember it
-
Mox3d
- E30 Zone Regular
- Posts: 661
- Joined: Sat Jul 08, 2006 11:00 pm
- Location: Telford and other really interesting places
- Contact:
JimmyC, understand exacty where you're coming from and would normally agree based on what I know traditionally with Kumho's and other manuf tyres but that goes directly against the guidlines given on the linked page thus 'Hot Inflation Pressures: High 30s to Low 40s (psi)'
If Toyo's R888 compound is a new blend etc bla bla why on Earth do we have such a disparity of guidelines ?
Email alan@toyotyre.co.uk Direct because it looks like this is going to go nowhere fast now. If the above info I sourced proves to be over Toyo's actual recommended pressures on the linked site I apologise and will contact them to update. I will email Alan myself and find out what I can independently. Until we have accurate and reliable info please ignore all my previous messages and accept my sincerest apologies.
If Toyo's R888 compound is a new blend etc bla bla why on Earth do we have such a disparity of guidelines ?
Email alan@toyotyre.co.uk Direct because it looks like this is going to go nowhere fast now. If the above info I sourced proves to be over Toyo's actual recommended pressures on the linked site I apologise and will contact them to update. I will email Alan myself and find out what I can independently. Until we have accurate and reliable info please ignore all my previous messages and accept my sincerest apologies.
-
Mox3d
- E30 Zone Regular
- Posts: 661
- Joined: Sat Jul 08, 2006 11:00 pm
- Location: Telford and other really interesting places
- Contact:
copy of email just this minute sent:
Hello Alan,
My name is Jan Mathiesen. I work with Moseley Motorsport here in the UK with race car prep a great deal and am also a registered members at www.e30zone.net where at the forum I have attempted to give what may well have been bad advice on guideline pressures for the Toyo R888 tyre as shown on this American website page http://www.1010tires.com/tire.asp?tireb ... roxes+R888
As you can see there are given guidelines upon the recommended tyre pressures but they go against adivice that has been given by another forum members who states that Toyo uk recommend 30 psi (he runs the pbmw series so I cannot refute this at all). The car in question is a road registered (non race, un-caged) BMW 325i of weight index approx 1200 kilo's. The gentleman asked about pressures for track days.
Can you possibly tell me what the pressures (or pressure range) should they be hot and cold respectively please. This matter needs a resolution as a matter of some urgency.
Thank you kindly in advance for taking the time to address this query.
Kind regards,
Jan.
Hello Alan,
My name is Jan Mathiesen. I work with Moseley Motorsport here in the UK with race car prep a great deal and am also a registered members at www.e30zone.net where at the forum I have attempted to give what may well have been bad advice on guideline pressures for the Toyo R888 tyre as shown on this American website page http://www.1010tires.com/tire.asp?tireb ... roxes+R888
As you can see there are given guidelines upon the recommended tyre pressures but they go against adivice that has been given by another forum members who states that Toyo uk recommend 30 psi (he runs the pbmw series so I cannot refute this at all). The car in question is a road registered (non race, un-caged) BMW 325i of weight index approx 1200 kilo's. The gentleman asked about pressures for track days.
Can you possibly tell me what the pressures (or pressure range) should they be hot and cold respectively please. This matter needs a resolution as a matter of some urgency.
Thank you kindly in advance for taking the time to address this query.
Kind regards,
Jan.
I thought I had made it clear that the info I posted came direct from Toyo.
In fact it came as a direct email to me from Alan Meaker.
I would not have posted unless I was 100% happy that the information was correct .
I very much doubt that they will give a definitive pressure for use in all conditions. As someone has already posted, this could change dependant upon all kinds of variables.
What IS important is the tread trmperature. If you look at the information in my previous post, what they are trying to achieve is a tread temp which falls in quite a narrow band (cant be bothered to look back at what it is now) and that this is achieved basically by trial and error (plus of course a bit of prior knowledge, if you've been there before) changing pressures and camber settings (if you can) to give optimum temps evenly across the tread.
Or you could ask the bloke down at Quick Fit - as a base setting frankly its just as likely to be right.
Kim
In fact it came as a direct email to me from Alan Meaker.
I would not have posted unless I was 100% happy that the information was correct .
I very much doubt that they will give a definitive pressure for use in all conditions. As someone has already posted, this could change dependant upon all kinds of variables.
What IS important is the tread trmperature. If you look at the information in my previous post, what they are trying to achieve is a tread temp which falls in quite a narrow band (cant be bothered to look back at what it is now) and that this is achieved basically by trial and error (plus of course a bit of prior knowledge, if you've been there before) changing pressures and camber settings (if you can) to give optimum temps evenly across the tread.
Or you could ask the bloke down at Quick Fit - as a base setting frankly its just as likely to be right.
Kim
-
Mox3d
- E30 Zone Regular
- Posts: 661
- Joined: Sat Jul 08, 2006 11:00 pm
- Location: Telford and other really interesting places
- Contact:
If an average guy in quick fit is going to be able to give you good advice on Toyo R888 pressures for track day use, specifically for a BMW e30 325, I want the branch number and his name because so help me that would be a real first and some incredible good luck!kimbo wrote:If you look at the information in my previous post, what they are trying to achieve is a tread temp which falls in quite a narrow band (cant be bothered to look back at what it is now) and that this is achieved basically by trial and error (plus of course a bit of prior knowledge, if you've been there before) changing pressures and camber settings (if you can) to give optimum temps evenly across the tread.
Or you could ask the bloke down at Quick Fit - as a base setting frankly its just as likely to be right.
Kim
Secondly, no, you did not specify the email was a personal response from Alan, with respect, you originally stated 'Toyo Motorports'. Not that Alan may nescessarily be the Toyo Oracle, it is fair to say that if we are talking about the very same Alan as per the email address given on the site he (theoretically) should cite the exact same guidelines as Toyo motorsports, in which case I will be getting in touch with the American site I linked to before and putting them right (if they happen to distribute the exact scame tyre to the US).
No point getting all wound up and twisted over this at all. We will find the right answers if they haven't already been posted by Jimmy C, Kimmel or the Us site I originally used for reference. This could serve as a reminder that on occasion we find ourselves waist high in a pool of variable information without a datum reference.
Hold fire, be cool and wait for responses. Lets see, because I now would very much like to know what Alan says.
-
Mox3d
- E30 Zone Regular
- Posts: 661
- Joined: Sat Jul 08, 2006 11:00 pm
- Location: Telford and other really interesting places
- Contact:
This is the document that arrived this morning attatched to a very courteous email from Alan Meaker. Reproduced with kind permission of Alan Meaker and Toyo Tyres Ltd. I offer no personal conclusions other than to suggest that running a rigid 30 psi isn't ideal and you will learn little. But also that the US site I linked to originally was optimistically high in thier pressure recommendations -
>>>>
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 ”aMy tyres started to go of towards the end of the race”a, 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. [/b]
>>>>
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 ”aMy tyres started to go of towards the end of the race”a, 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. [/b]
Didnt mean to sound arsey, just to point out that I had already posted the 'official' Toyo info.
Alan has now expanded a little more into car setup, it seems - best of luck there, as its all so variable depending on style, etc.
BTW Alan is their motorsport manager - if my referance to 'competition department' caused confusion, then I apologise.
The referance to Kwick Fit was a jockey way of pointing out that there aint no hard and fast rule - as your last post, which I will point out is repeating the info I posted earlier, albeit with additional setup suggestions, more than adequately verifies.
Happy inflating!
Kim
Alan has now expanded a little more into car setup, it seems - best of luck there, as its all so variable depending on style, etc.
BTW Alan is their motorsport manager - if my referance to 'competition department' caused confusion, then I apologise.
The referance to Kwick Fit was a jockey way of pointing out that there aint no hard and fast rule - as your last post, which I will point out is repeating the info I posted earlier, albeit with additional setup suggestions, more than adequately verifies.
Happy inflating!
Kim
-
Mox3d
- E30 Zone Regular
- Posts: 661
- Joined: Sat Jul 08, 2006 11:00 pm
- Location: Telford and other really interesting places
- Contact:
All good lol. Happy dayskimbo wrote:Didnt mean to sound arsey, just to point out that I had already posted the 'official' Toyo info.
Alan has now expanded a little more into car setup, it seems - best of luck there, as its all so variable depending on style, etc.
BTW Alan is their motorsport manager - if my referance to 'competition department' caused confusion, then I apologise.
The referance to Kwick Fit was a jockey way of pointing out that there aint no hard and fast rule - as your last post, which I will point out is repeating the info I posted earlier, albeit with additional setup suggestions, more than adequately verifies.
Happy inflating!
Kim
