tyre pressures
Discussion
Butzi said:
phatgixer said:
What an appalling plug for your site, Butzi! 
not meant to be a plug, but it does have a fair bit of useful basic info and I coouldn't be bothered to type it all out, or copy and paste the lot. 
Scally
Need For Speed said:
The general rule of thumb for hooning it about on trackdays is to set your tyre pressures to the maximum load recommendation as detailed in your manual. These are normally around 5-6 psi over the normal "2 up with no luggage" pressures.
High speed running might need higher pressures, but for track work you need exactly opposite. Boyles law comes into play as he temperature rises (due to friction in the steel / rubber) and the gas wants to expand, increasing pressure. This needs to be predicted and generally you will need to bleed off something in the region of 6-7 psi before you go on track.My cups on my RS are set to 25psi cold to attain 33psi hot. This is some 10 psi lower than the handbook suggests for road work. Car is epic on the pressures. Run at road pressure would be like running on ice after a few laps as the pressure would balloon the tyre and decrease the contact patch and over heating that section of rubber. Slidy time!
So, do not pump UP your tyres on a trackday!
the general answer is "all of the above"
if you are using std road tyres, you need to run a couple of psi above normal pressure to maintain the tyre shape under excessive side loads...BUT READ ON!
if running road slix like R888s or similar, the tyres will have a stronger construction and may not need this. (If you are running them on a lightweight sports/track car the pressures may have already been reduced to limit tramlineing etc...so the above will apply again!!!
the tyres will generate alot of pressure as they get used...around 7-10psi is not unusal as previously mentioned, so you need to lower the pressures to account for this.
Experienced guys know where all this takes them and it is dependant on ambient temps, weather etc. We for example like to run at 30psi HOT in dry conditions, so experience tells us that on a "normal" day we need around 21-22psi in our tyres when cold (the front left being 21 and 22 around the car).
To find your own, increse pressures by 2 psi when arriving at the Track. As your sessions go during the day, check and reduce your pressures throughout the day using an accurate guage...maintaining your initial level. Check your pressures as soon as possible when coming in! Temps will fall at a serious rate when off the gas, so keep a healthy speed up on the cool down lap (best you safely can) and maybe weave a bit to keep the heat. Pull up asap in the paddock. ie don't drive 1.5miles around the paddock back to your garage or bay and have a chat before checking.
This done...at the end of the day, pack up all your kit, chat with your mate...THEN CHECK PRESSURES AGAIN, COLD! This will be your starter pressure for the next Track day.
Finally, remember to pump them back up before you leave!!! You may well be driving home with only 16psi in your Rubber!!!
Essentials...a compressor...a decent pressure guage!
if you are using std road tyres, you need to run a couple of psi above normal pressure to maintain the tyre shape under excessive side loads...BUT READ ON!
if running road slix like R888s or similar, the tyres will have a stronger construction and may not need this. (If you are running them on a lightweight sports/track car the pressures may have already been reduced to limit tramlineing etc...so the above will apply again!!!
the tyres will generate alot of pressure as they get used...around 7-10psi is not unusal as previously mentioned, so you need to lower the pressures to account for this.
Experienced guys know where all this takes them and it is dependant on ambient temps, weather etc. We for example like to run at 30psi HOT in dry conditions, so experience tells us that on a "normal" day we need around 21-22psi in our tyres when cold (the front left being 21 and 22 around the car).
To find your own, increse pressures by 2 psi when arriving at the Track. As your sessions go during the day, check and reduce your pressures throughout the day using an accurate guage...maintaining your initial level. Check your pressures as soon as possible when coming in! Temps will fall at a serious rate when off the gas, so keep a healthy speed up on the cool down lap (best you safely can) and maybe weave a bit to keep the heat. Pull up asap in the paddock. ie don't drive 1.5miles around the paddock back to your garage or bay and have a chat before checking.
This done...at the end of the day, pack up all your kit, chat with your mate...THEN CHECK PRESSURES AGAIN, COLD! This will be your starter pressure for the next Track day.
Finally, remember to pump them back up before you leave!!! You may well be driving home with only 16psi in your Rubber!!!
Essentials...a compressor...a decent pressure guage!
phatgixer said:
So, do not pump UP your tyres on a trackday!
Sorry but I disagree. Lowering your tyre pressures and then hooning it about on a track day will scrub them out, prematurely overheat them, give you poor grip and feedback, and that's if you're lucky enough for them to stay on the rims. Talk to any expert and they will confirm this. I did, Ron Simons at RS Racing, the Nurburgring meister, can't be b*llsh*tting!Need For Speed said:
phatgixer said:
So, do not pump UP your tyres on a trackday!
Sorry but I disagree. Lowering your tyre pressures and then hooning it about on a track day will scrub them out, prematurely overheat them, give you poor grip and feedback, and that's if you're lucky enough for them to stay on the rims. Talk to any expert and they will confirm this. I did, Ron Simons at RS Racing, the Nurburgring meister, can't be b*llsh*tting!Guillotine said:
the general answer is "all of the above"
if you are using std road tyres, you need to run a couple of psi above normal pressure to maintain the tyre shape under excessive side loads...BUT READ ON!
if running road slix like R888s or similar, the tyres will have a stronger construction and may not need this. (If you are running them on a lightweight sports/track car the pressures may have already been reduced to limit tramlineing etc...so the above will apply again!!!
the tyres will generate alot of pressure as they get used...around 7-10psi is not unusal as previously mentioned, so you need to lower the pressures to account for this.
Experienced guys know where all this takes them and it is dependant on ambient temps, weather etc. We for example like to run at 30psi HOT in dry conditions, so experience tells us that on a "normal" day we need around 21-22psi in our tyres when cold (the front left being 21 and 22 around the car).
To find your own, increse pressures by 2 psi when arriving at the Track. As your sessions go during the day, check and reduce your pressures throughout the day using an accurate guage...maintaining your initial level. Check your pressures as soon as possible when coming in! Temps will fall at a serious rate when off the gas, so keep a healthy speed up on the cool down lap (best you safely can) and maybe weave a bit to keep the heat. Pull up asap in the paddock. ie don't drive 1.5miles around the paddock back to your garage or bay and have a chat before checking.
This done...at the end of the day, pack up all your kit, chat with your mate...THEN CHECK PRESSURES AGAIN, COLD! This will be your starter pressure for the next Track day.
Finally, remember to pump them back up before you leave!!! You may well be driving home with only 16psi in your Rubber!!!
Essentials...a compressor...a decent pressure guage!
Good post if you are using std road tyres, you need to run a couple of psi above normal pressure to maintain the tyre shape under excessive side loads...BUT READ ON!
if running road slix like R888s or similar, the tyres will have a stronger construction and may not need this. (If you are running them on a lightweight sports/track car the pressures may have already been reduced to limit tramlineing etc...so the above will apply again!!!
the tyres will generate alot of pressure as they get used...around 7-10psi is not unusal as previously mentioned, so you need to lower the pressures to account for this.
Experienced guys know where all this takes them and it is dependant on ambient temps, weather etc. We for example like to run at 30psi HOT in dry conditions, so experience tells us that on a "normal" day we need around 21-22psi in our tyres when cold (the front left being 21 and 22 around the car).
To find your own, increse pressures by 2 psi when arriving at the Track. As your sessions go during the day, check and reduce your pressures throughout the day using an accurate guage...maintaining your initial level. Check your pressures as soon as possible when coming in! Temps will fall at a serious rate when off the gas, so keep a healthy speed up on the cool down lap (best you safely can) and maybe weave a bit to keep the heat. Pull up asap in the paddock. ie don't drive 1.5miles around the paddock back to your garage or bay and have a chat before checking.
This done...at the end of the day, pack up all your kit, chat with your mate...THEN CHECK PRESSURES AGAIN, COLD! This will be your starter pressure for the next Track day.
Finally, remember to pump them back up before you leave!!! You may well be driving home with only 16psi in your Rubber!!!
Essentials...a compressor...a decent pressure guage!
phatgixer said:
Need For Speed said:
phatgixer said:
So, do not pump UP your tyres on a trackday!
Sorry but I disagree. Lowering your tyre pressures and then hooning it about on a track day will scrub them out, prematurely overheat them, give you poor grip and feedback, and that's if you're lucky enough for them to stay on the rims. Talk to any expert and they will confirm this. I did, Ron Simons at RS Racing, the Nurburgring meister, can't be b*llsh*tting!Need For Speed said:
phatgixer said:
So, do not pump UP your tyres on a trackday!
Sorry but I disagree. Lowering your tyre pressures and then hooning it about on a track day will scrub them out, prematurely overheat them, give you poor grip and feedback, and that's if you're lucky enough for them to stay on the rims. Talk to any expert and they will confirm this. I did, Ron Simons at RS Racing, the Nurburgring meister, can't be b*llsh*tting!There is circa E4k excess on those cacked out old £500s worth of old Alfas, hence its in his interest when punters spank em
Another plug:
http://www.macgracing.co.uk/trackdays_setup1.html
Bottom two paragraphs are what you want but the rest is interesting if you like that kind of thing
Jonny
http://www.macgracing.co.uk/trackdays_setup1.html
Bottom two paragraphs are what you want but the rest is interesting if you like that kind of thing
Jonny
phatgixer said:
Guillotine said:
the general answer is "all of the above"
if you are using std road tyres, you need to run a couple of psi above normal pressure to maintain the tyre shape under excessive side loads...BUT READ ON!
if running road slix like R888s or similar, the tyres will have a stronger construction and may not need this. (If you are running them on a lightweight sports/track car the pressures may have already been reduced to limit tramlineing etc...so the above will apply again!!!
the tyres will generate alot of pressure as they get used...around 7-10psi is not unusal as previously mentioned, so you need to lower the pressures to account for this.
Experienced guys know where all this takes them and it is dependant on ambient temps, weather etc. We for example like to run at 30psi HOT in dry conditions, so experience tells us that on a "normal" day we need around 21-22psi in our tyres when cold (the front left being 21 and 22 around the car).
To find your own, increse pressures by 2 psi when arriving at the Track. As your sessions go during the day, check and reduce your pressures throughout the day using an accurate guage...maintaining your initial level. Check your pressures as soon as possible when coming in! Temps will fall at a serious rate when off the gas, so keep a healthy speed up on the cool down lap (best you safely can) and maybe weave a bit to keep the heat. Pull up asap in the paddock. ie don't drive 1.5miles around the paddock back to your garage or bay and have a chat before checking.
This done...at the end of the day, pack up all your kit, chat with your mate...THEN CHECK PRESSURES AGAIN, COLD! This will be your starter pressure for the next Track day.
Finally, remember to pump them back up before you leave!!! You may well be driving home with only 16psi in your Rubber!!!
Essentials...a compressor...a decent pressure guage!
Good post if you are using std road tyres, you need to run a couple of psi above normal pressure to maintain the tyre shape under excessive side loads...BUT READ ON!
if running road slix like R888s or similar, the tyres will have a stronger construction and may not need this. (If you are running them on a lightweight sports/track car the pressures may have already been reduced to limit tramlineing etc...so the above will apply again!!!
the tyres will generate alot of pressure as they get used...around 7-10psi is not unusal as previously mentioned, so you need to lower the pressures to account for this.
Experienced guys know where all this takes them and it is dependant on ambient temps, weather etc. We for example like to run at 30psi HOT in dry conditions, so experience tells us that on a "normal" day we need around 21-22psi in our tyres when cold (the front left being 21 and 22 around the car).
To find your own, increse pressures by 2 psi when arriving at the Track. As your sessions go during the day, check and reduce your pressures throughout the day using an accurate guage...maintaining your initial level. Check your pressures as soon as possible when coming in! Temps will fall at a serious rate when off the gas, so keep a healthy speed up on the cool down lap (best you safely can) and maybe weave a bit to keep the heat. Pull up asap in the paddock. ie don't drive 1.5miles around the paddock back to your garage or bay and have a chat before checking.
This done...at the end of the day, pack up all your kit, chat with your mate...THEN CHECK PRESSURES AGAIN, COLD! This will be your starter pressure for the next Track day.
Finally, remember to pump them back up before you leave!!! You may well be driving home with only 16psi in your Rubber!!!
Essentials...a compressor...a decent pressure guage!
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