bonerp
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| posted on 17/6/04 at 10:11 AM |
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Track Day and tyre pressures
Hi, Got a track day tomorrow and was wondering if I should reduce my tyre pressures a bit? They are at about 18PSI currently.
I know on bikes I reduced them, not sure on this.
Paul
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phelpsa
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| posted on 17/6/04 at 11:15 AM |
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No, If anything I would raise them to about 22psi.
Adam
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bonerp
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| posted on 17/6/04 at 12:55 PM |
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But surely when the tyres warm up they will gain more pressure?
With bikes it increases the contact patch...hmmm may have just answered my own question!
Paul
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Jasper
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| posted on 17/6/04 at 02:23 PM |
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Gotta disagree with Adam, everbody I know runs at about 16psi (I do all the time).
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mackie
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| posted on 17/6/04 at 02:49 PM |
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I'm not that clued about pressures.
I run my 1000kg Puma at 32/30 f/r (slightly more than standard due to softer walls of toyo tyres vs pirelli).
Is it generally a rule that half the weight = half the pressure?
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phelpsa
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| posted on 17/6/04 at 03:18 PM |
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I have been going by what the people on Blatchat say. They generally run their tyres around 18psi for road and 22-24 for trackdays.
Adam
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Jon Ison
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| posted on 17/6/04 at 03:38 PM |
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My 2p
I run 12psi all round during a race this rises to around 14-15psi
best way (i find) is to measure tyre temps across the full width ASAP after coming off track, your looking for an even temp across the full width.
Hotter in middle= to high
Hotter on edges= to low....
All IMHO of course.
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zilspeed
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| posted on 17/6/04 at 03:42 PM |
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At my Knockhill day I had 18psi all round. Xflow engine remember.
That was with the 15" wheels and the 195/45 tyres. The wear was generally even right across the treads and so was the light bobbling - so the
tyres had heated evenly as well.
I'll stop here before subk2002 reads too much into this tyre torture.
Allright there drew :-)...........
Looking forward to trying the yokos once they arrive.
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blueshift
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| posted on 17/6/04 at 05:30 PM |
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bloke i was talking to about track days said his tyres tend to wear heavily on the outside on track days at road pressures, so he ups the pressure for
the track to even out the wear.
made sense to me.
actually this was wrt. a drifting day so maybe different.
[Edited on 17/6/04 by blueshift]
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Findlay234
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| posted on 17/6/04 at 07:58 PM |
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cant you go to the track day and then vary the pressures to see which one works best???
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locost_bryan
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| posted on 17/6/04 at 10:05 PM |
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The door tag on most road cars recommend 2-4 psi extra for higher speeds - the increased pressure effectively stiffens the sidewall and reduces the
heat generated by the carcase flexing.
When I raced Mini's, I ran 40psi  on the front and 30 psi rear. For the road I ran 32/28. Didn't do much for the ride, but helped
reduce the fwd understeer. 
Seems to me most of the locost's ride compliance is in the tyres, judging by the sub 20psi pressures most use. This must allow more sidewall
flex.
As all our cars are unique, the only way is to suck it and see... 
Bryan Miller
Auckland NZ
Bruce McLaren - "Where's my F1 car?"
John Cooper - "In that rack of tubes, son"
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