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AD08S gone blue.
- Thread starter PBCup
- Start date
182cup & 172 racecar
Not the end of the world, but they have got too hot.
These sort of tyres need looking after.
These sort of tyres need looking after.
imprezaworks
ClioSport Club Member
Mk5 Golf GTI :)
Tony do you rate these tyres, I'm getting a set fitted tomo or fri if they turn up
What pressures were you using?Mine were perfect at llandow!!
182cup & 172 racecar
They ain't too bad for a road tyre.
Don't let them get below -10 though.
Don't let them get below -10 though.
WRX
Mine were perfect at llandow
I can vouch for that mate, they felt pretty good from the passenger seat. I was impressed with them, be interesting to feel from a driving point of view and pushing them just that bit more.
imprezaworks
ClioSport Club Member
Mk5 Golf GTI :)
Only one way to find out I guess. It was a toss up between a few different makes. These seemed to tick a few more boxes
What were your hot pressures?
imprezaworks
ClioSport Club Member
Mk5 Golf GTI :)
So what's a good starting pressure?
Not sure didnt test them. Cold was 32psi
imprezaworks
ClioSport Club Member
Mk5 Golf GTI :)
I'm no expert but lol at 32 cold
We started at 24 front and 26 rear at llandow, and the front pass side still went upto 34 so we let some back out.
182cup & 172 racecar
Lol.
JamesBryan
ClioSport Club Member
Book says 30 rear, 33 front for road.
Yup thought as much, lol.
JamesBryan
ClioSport Club Member
Obviously couldn't leave it like that and go out on track, would be well into the 40's when hot.
JamesBryan
ClioSport Club Member
Oh yeah definitely, lad that asked never mentioned being on track
Ahh you're right. Why ask about normal pressures in a track tyre thread though
182cup & 172 racecar
If you do a bit of hooning on a hot day, they will soon get very hot.
Has anybody checked their tyre pressures after a quick blast up the road..... No, thought not.
Has anybody checked their tyre pressures after a quick blast up the road..... No, thought not.
I have
But I'm going with "was curious as to the temperature addition on a road car in comparison with a race car" as opposed to "being anal" though...
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182cup & 172 racecar
And your findings were ??
My findings were that pressure increases with temps in line with boyles law as expected but therefore not as much as on track as temps weren't as high.
182cup & 172 racecar
Frankie Boyles tell a good joke or two.
Funny live also!
Interesting thread, but it just reinforces my opinion that by far the best way to go about tyre pressures is to just forget theory & set them when hot. So many variables to account for, that theory takes too long compared to a few installation laps.
Only when you have a lot of constants (a driver that works the tires sufficiently, a setup that doesn't change massively) and some past data is it viable to start making improvements to any predictions based on PV=nRT. When you really think about it, you realise that not a single letter in that equation is a simple one.
The average hard compound racing slick (sports & production, no idea about formula cars) has an operating window of what, 80 - 100 degrees Celsius. How many club racers let alone track day drivers achieve that surface temp with the sort of ambient temp we get in the UK.
Only when you have a lot of constants (a driver that works the tires sufficiently, a setup that doesn't change massively) and some past data is it viable to start making improvements to any predictions based on PV=nRT. When you really think about it, you realise that not a single letter in that equation is a simple one.
The average hard compound racing slick (sports & production, no idea about formula cars) has an operating window of what, 80 - 100 degrees Celsius. How many club racers let alone track day drivers achieve that surface temp with the sort of ambient temp we get in the UK.
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imprezaworks
ClioSport Club Member
Mk5 Golf GTI :)
Fitted mine and they feel good with the minimal mileage done. So when on track from cold set them to what? Then after a couple of laps and check what they go to when hot. So my question and feel free to fill the blanks chaps
cold______psi.
hot_______psi.
cold______psi.
hot_______psi.
182cup & 172 racecar
I can get mine up to 80deg, with a 10 deg difference across the tyre width.
A day like today I would start at f 24 psi r 27 psi, then check after every 3 laps.
Have started with the fronts as low as 19 psi before now.
A day like today I would start at f 24 psi r 27 psi, then check after every 3 laps.
Have started with the fronts as low as 19 psi before now.
Drop cold pressures maybe 7 PSI front, 3 PSI rear (from road car 33/30)
Do 3 - 5 laps (lower lap count if you're car/driver isn't working the tyres much, higher lap count if you're working the tyres properly & getting brake temp (thus the all important wheel temp!)).
Pit & drop tyre pressures to your target pressure (rule of thumb is 2.0 bar hot as a baseline to start from for a racing slick).
At end of session wait till tyres cool down to ambient temp.
Take cold pressure from each tyre.
That will give you a good starting point for cold pressures for those exact conditions. Then adjust (by trial and error) depending on tyre wear, wear patterns, track layout, car setup, driver etc (the list is endless)
Where does 7/3 PSI come from? Needing a safe cold pressure & the fact that it's far easier to bleed air than add (cold) air to a (hot) tyre.
Where does 3-5 laps come from? A good assumption for when temps & pressures stabilise for this thread.
Where does 2.0 bar come from? This is a fair "average" value given by tyre manufacturers for racing slicks. Pressure creates structure & therefore mechanical grip. Temp creates chemical grip through tearing the tyre surface (on a teeny tiny microscopic scale) and revealing fresh rubber
Why take a pressure from each tyre? Because, if the tyres are being worked, each corner will experience a different amount of load, therefore generate a different amount of heat, therefore expand the air in the tyre a different amount, therefore needing different cold pressures to ensure everything comes up to the same pressure when hot.
Have you tried to get tyre data off of a manufacturer's website before Let me know when you find anything more detailed than rolling circumferences or (at a stretch!) operating windows for pressures and temps.
Do 3 - 5 laps (lower lap count if you're car/driver isn't working the tyres much, higher lap count if you're working the tyres properly & getting brake temp (thus the all important wheel temp!)).
Pit & drop tyre pressures to your target pressure (rule of thumb is 2.0 bar hot as a baseline to start from for a racing slick).
At end of session wait till tyres cool down to ambient temp.
Take cold pressure from each tyre.
That will give you a good starting point for cold pressures for those exact conditions. Then adjust (by trial and error) depending on tyre wear, wear patterns, track layout, car setup, driver etc (the list is endless)
Where does 7/3 PSI come from? Needing a safe cold pressure & the fact that it's far easier to bleed air than add (cold) air to a (hot) tyre.
Where does 3-5 laps come from? A good assumption for when temps & pressures stabilise for this thread.
Where does 2.0 bar come from? This is a fair "average" value given by tyre manufacturers for racing slicks. Pressure creates structure & therefore mechanical grip. Temp creates chemical grip through tearing the tyre surface (on a teeny tiny microscopic scale) and revealing fresh rubber
Why take a pressure from each tyre? Because, if the tyres are being worked, each corner will experience a different amount of load, therefore generate a different amount of heat, therefore expand the air in the tyre a different amount, therefore needing different cold pressures to ensure everything comes up to the same pressure when hot.
Have you tried to get tyre data off of a manufacturer's website before
Let me know when you find anything more detailed than rolling circumferences or (at a stretch!) operating windows for pressures and temps.
imprezaworks
ClioSport Club Member
Mk5 Golf GTI :)
182cup & 172 racecar
I know that ^
The one above.
And yes, manufacturer's are very sketchy when it comes to this information.
The one above.
And yes, manufacturer's are very sketchy when it comes to this information.
