scoobyc

iTrader: (2)

Hi,

Was wondering what pressure i should have my tyres at? they are 16" on a 98 sti v4.

What pressure should i have for the track? Up 2 psi?

dynamix

iTrader: (3)

Depends on the tyres - if they are Toyo T1-R then put them up a few PSI until they arent rolling over too much and scrubbing out the writing on the side of the tyre.

Ginge !

iTrader: (1)

what !!!!


mate 25 to 28psi, then find if they are rolling over a little more or a little less if they feel slidey

NEVER more than road presure at all !!!

tyres get hotter so will naturally have more presure in them when they get warm,,, which means less surface area contact

oh and tyres have nothing to do with presure either,, the car is what is important with the presure

dynamix

iTrader: (3)

rubbish

Ginge !

iTrader: (1)

your experience comes from where ??

you tired both ideas im assuming,, when i was at the ring my impreza was sliding all over the shop like a bitch so came back as was told " check your presure" and i had 42psi in them !!

next day i lowered it to 28psi before i went out and the car was less like its on ice and gripped better, rolling over happened when i went to 25psi that everyone there seemed to recomend bbutut hey was using r888/a048 tyres and i was using normal road tyres

the only tyre pressure you EVER use is the recomended,,,, changing wheels for larger and tyre diameters you stil use the same recomended presures in general use also

interested to see where your info comes from though as everyone has different ideas but generally lower pressures give more grip at the expence of fuel economy ect,,, higher presures give less resistance at the expence of grip,,,,,, now on track tyres get VERY hot compared to road use,,,,, hot air will increase psi

if your at donnington on the 29th we can take notes on the feel of the cars on track D:

Moley

iTrader: (9)

Yeah Duncan, what do you know about driving on track?!?!

dynamix

iTrader: (3)

So you would run identical pressures on a hard sidewalled tyre like A048R/RE070 and soft sidewalled Toyo T1-R then as they are on the same car and that is the only thing that matters to you?

Ginge !

iTrader: (1)

that wasnt what i ment, theres loads of people who drive cars/work in thing that dont try other ideas due to being told " it dont work"

as said ive done not done many track days but i have been to alot and got alot of mates who do ALOT of track days,,, they all say the same as i was told,,, one of em lowered my presures and,,,,, well as if my magic the car gripped better than before, rolling over is also caused by harsh cornering also,, as in tugging the wheel for corners rather than smooth movements,,, again something i do as i enjoy a little slide at times till it goes wrong

unless your saying cause someone does track days he must know everthing so we should not question what we have test and already discovered ??

Ginge !

iTrader: (1)

no i would start by testing to see what happens,, and going up the pressure seems a crazy way to test considering alot of variables here too

as said people i know run 25psi on dunlop slicks/a040's/r888's,,,, they run fine but i was rolling over on normal road tyres,,, i found 28psi cold seemed to be the best balance,,,,, i couldnt even tell you what tyres i was running they either as i just got the car to start doing track days and picked up the car a few weeks before my ring trip

i got a vid of a mate of mine driving JC's clio quite hard ill admit,,,, jc at the wheel and the tyres where fine,,,, my mate driving it and he wore off the writing off the tyre wall so the next lap presure in the tyre went up,,another example of driving style vs tyres

rooferman

iTrader: (6)

I run my r888 with more pressure for track...........30psi suits me.

Ginge !

iTrader: (1)

i aint got a clue what im gonna run my r888's for the track yet, im gonna start on 30 and work it out from there as ive yet to use em

dynamix

iTrader: (3)

Not (necessarily) true. The higher the tyre pressure, the greater the cornering force for a given slip angle at a certain load. There are limits to this though and it does vary per tyre and other factors like geometry, body roll come into play too.

Measuring tyre pressures is only really useful in conjunction with tyre temperatures. Having tow low a pressure can mean that the rubber on the tyre will move too much and will heat up excessively. This, again varies by tyre mfr and type as the Yoko A048R and RE070 moves a lot less than 888's from my experience and vastly less than T1-Rs or F1.

Sadly I wont be at Donington as I am over at the ring for a week. I will have to save that for Time Attack again next spring.

Measuring cold pressures is irrelevant for track use. My experience is first hand - in the qualifying at Time Attack at Snetterton a 4 PSI increase in tyre pressures on one end of the car during qualifying netted an extra second and a half quicker the next lap. Its about managing the tyre temperatures and measuring what the temps are across the tread.

Ginge !

iTrader: (1)

interesting,,, honestly is as said im going based on not one persons opinion but a few who do track days and also seperate groups too, not all the same group as you can get a little blinkerd if you get what i mean

ive notived that my full race slicks have very very hard tyre walls compared to the other tyres ive got, but never even thought about that as a variable

i have noticed that A048's seem to last longer with people than r888's though with a few people who have changed over tyres

what tyres do you use from most track days out of interest ?

ps: hope your taking a set of snow chains if your going to the ring in december

dynamix

iTrader: (3)

Track tyres have been 888's this year because of the tie up with Time Attack but have run A048's on track through last year at around 10 track days and I personally prefer the A048 for the ring as the 888's can get too hot on a couple of consecutive laps. (better ultimate grip though I think)

Through the 2008 TA season we have had technical advice from Toyo themselves on getting the most out of the tyres and at Snetterton I also support from 2007 TA champions Zen and I think Paul knows a couple of things about car suspension and tyre set up

Understanding what is happening helps to understand how to deal with the issues but lower pressures on a std softwalled tyre is not what I would recommend to go back to the OP's question.

Re the ring...snow will be fine, if its snowing there we will do a few driftee laps or if we cant persuade the marshalls to open it up for us we will sledge down fuchsrohre to see if we can make it up the other side of the hill

Ginge !

iTrader: (1)

fair play for giving it a goe at the ring. was watching a vid of last year that jc took with hes mate whos got the audi with orange stickers on it that arranges the trips,,,,,, they got stuck 3/4 of the way and had to come BACK due to the hills,,,,, honestly looking at the ring in reverse looks alot steeper,,, they came off at adenau and the hill you go up after the entrance,,,, thats alot steeper comming back on film,,,, sod actually doing it in snow

dynamix

iTrader: (3)

Going out for the social side in reality with some friends that we know and spend a week over there with in the summer - if it is open, then great if not, there is so much else to do in a beautiful part of the world.

Cant beat sliders on new year's eve with great friends

i saw JC's clio lap - there was some discussion about it on northloop

Ginge !

iTrader: (1)

yeah i know,,,,, shame it wasnt jc driving though pmsl

i was the camera man btw, a bloke from another forum i bumped into over there,,, never even met jc before either

anyway took me out for a lap,,,,,,, was proper fun has to be said and the following year jc took me out for a lap in hes type ra,,,,, they can pedal a car like you wont belive,,,,, my missus wasnt conviced though,,,,, she was in the back and threw up after it poor girl,,,,,,, but thats mainly as its the second lap shes had as a passenger NOT me,,,,, both with jc

jc has a heart of gold, i know theres some discussions about him taken the wrong way but go on any track with him or anyone he knows as its all about fun

dont forget hes a grandfather too !!! pmsl

he could tidy hes lines up at the ring and get even better times,,, which at the moment hes flying anyway but he does it for fun which is what i respect about him

Moley

iTrader: (9)

Duncan - do you find the R888s 'go off' at all on normal UK tracks?
If so how many laps do you get from them (on a 1.5-2 mile circuit for example)

scoobyc

iTrader: (2)

so 28 then

dynamix

iTrader: (3)

On what tyres?

Hot pressure / Cold Pressure ????

Moley .. weird one I initially thought they did but they seem to lose grip once they get hot but getting them even hotter seems to bring them back.

scoobyc

iTrader: (2)

tbh all my tyres are different. Suicide i know.

We have Kumo something.
Bridgeston Potenza (p1?)
and 2 on the front of no brand i can find.

Cold pressure.

dynamix

iTrader: (3)

good luck

When/where is your track day ?

scoobyc

iTrader: (2)

sunday. ill be alright. And if im not, as long as i dont die or kill anyone. Happy days.

Atleast ill be able to report how much of an effect these will cause. I suspect not much for the conditions/my first track day.