Handy tips for track day virgins

[james]

Setve Carter (GetCarter) has put together a very good page of advice for newcomers to track days. Well worth a look

www.stevecarter.com/track-day-beginners.htm

James

[RichB]

Interesting point here, on his web-page Steve mentions increasing tyre pressure by a couple of psi. which is I believe common practice. At Bedford last week, in his pre-track briefing, Jonathan Palmer suggested increasing pressures by 10 psi. This caused some muttered discussion, so over lunch I asked Neill Anderson (TVR Engineer) what he reckoned and he said "Yes 10psi. sounds about right", so what's the view here chaps? Rich...

[jeremyc]

I had always understood a 10% increase, not 10psi (although they sound nearly the same ).

I just assumed Dr. Palmer had got a little muddled....

[james]

The suggestions are just that. Suggestions. A common practice is to up the tyre pressures by 10% (if 10% is 10 psi on your tyres Jeremy, you're running them too high). However, these suggestions should be taken as a guide only. Depending on your car, it's weight, track conditions, temperature and your driving style, you may want to vary your tyre pressures by more or less (or even lower the pressures under certain circumstances).

The best thing to do if you aren't sure is to find an experienced driver, who has a similar car to you and ask him what he's doing, and why.

James

[Leadfoot]

www.circuitdriver.com/ has some good advice on it. road test etc good as well.


>> Edited by Leadfoot on Monday 2nd September 12:55

[shpub]

quote:
Interesting point here, on his web-page Steve mentions increasing tyre pressure by a couple of psi. which is I believe common practice. At Bedford last week, in his pre-track briefing, Jonathan Palmer suggested increasing pressures by 10 psi. This caused some muttered discussion, so over lunch I asked Neill Anderson (TVR Engineer) what he reckoned and he said "Yes 10psi. sounds about right", so what's the view here chaps? Rich...

Neil works for the factory. Factory generates money from selling bodywork for crash repairs. I found that +10 lb was way too much and I usually ended up in the gravel as the car was like driving on ice. I think there may be a conspiracy going on here...

It is as James says a guide and many other factors can come into play. I found that 30-31 was 2-3 lbs too high on both the Griff and Cerbera. As tyre pressures can be used to tune the car response, what suits some people doesn't suit others. On wet or dampish circuits I'll use road pressures or maybe 2-3 lb extra.

If you ask someone, make sure they have the same tyres and wheel sizes as you...

Steve

[getcarter]

I'm sure you're right when you say it depends on the weight and characteristics of the car (and the tyre) - on my M3 I put them up by about 2 lb to get the best grip in the dry, but leave them as is for wet - on my Caterham (ACB10's) I take them down (to about 15 psi) in the dry - in the wet I spin off on the first corner, so it's not an issue.

I think taking the pressure as soon as you get off track after a thrash is always the best way to at least find out how the tyres are doing (when compared to the heat generated on the other 3 corners). Then I think it's trial and error - until you find the most grip.

Steve

>> Edited by getcarter on Monday 2nd September 13:25

[RichB]

quote:Neil works for the factory. Factory generates money from selling bodywork for crash repairs.

Oh come on Steve, you getting jaundiced in your old age or what!!! Whatever you think of Neil I can't imagine he'd purposly send someone out with the intention of getting them to prang their car, anyway making a Griff nose-cone would probably be an irritation to the factory now I take your point about the pressures though and as it happens I felt comfortable on about 26-28 all-round. Rich...

[Pete Cros]

IMHO, I find that its not so cut and dried. Yes, most 'experts' recommend increasing tyre pressures for track use. However, you will find that nearly all 944 drivers decrease their tyre pressures for track days. I have experimented with different pressures, and different size tyres. Normal road use I under inflat tyres by 2 lb. On track I decrease pressures by a further 5 lb. This is COLD tyres. Run a few laps, and again decrese pressures to match the road/cold pressure. That is, I run track pressures at HOT the same pressure as road/cold. Someone else has done a more scientific experiment. On track, draw a chalk line across the tyre. Experiment with pressures and temperatures until the chalk mark left on the tarmac is the full width of the tyre. Get the idea. This person, again a 944 turbo driver, runs his tyres at extreemly low pressures.

So, its a matter of try it and see. If the tyres are warm/hot, and are letting go in the corners, try decreasing pressures a few lbs, and see if there is a difference.

The ideal is to get the full width of your tyre onto the surface of the track. Overpressure (rounded cross section) will make the car slide more.

But, I admit, this might not apply to all cars. Its just what 944 owner/drivers have found.

BTW for road use, later 944 turbo handbooks say 44lb rears. I, and many others, run 34/36 lb rears. The handbook 44lb is for high speed autoban use. Again, track use is different from autobans.

Racing 944 turbos run between 20 and 26 lb rears.

[powelly]

Does this have to be adjusted i.e. outside tyres at brands Indy circuit take a lot more hammer... get hotter and pressure increases during the day... should this be reduced to level inside and outside as the temp increases... maybe it doesn't make a difference..?

[jmorgan]

I have been told not to bother with pressure changes if its your first time etc until you are used to whats going on? I assume on the basis that you won't be pushing the limits the first couple of go's. After that start playing?

[Pete Cros]

Yep, I agree with all that you say. Until you have some experience of how the car handles, leave all settings alone. But, your tyres and brakes will take a hammering on any trackday. I keep my pressures identical for nearside and offside, I check them after nearly every session on track. Yes, the nearside tyres wear the fatest, I shredded a nearside front at Silverstone recently.

I'm *not* suggesting that you should follow any of my advice/comments, its just that the idea that you should increase tyre pressures for track days is *not* a hard and fast/set in stone rule.

Another issue is: for safety reasons, most production cars are setup with understeer. Changing camber angle for track days use, has a big impact on how the car turns into corners, and therefore tyre pressures.

As I hinted before, get your tyres warm/hot, check pressures, when the car starts to break away on corners, remove some air from the tyres.

[getcarter]

Good advice methinks Pete

[shpub]

quote:
Oh come on Steve, you getting jaundiced in your old age or what!!! Whatever you think of Neil I can't imagine he'd purposly send someone out with the intention of getting them to prang their car, anyway making a Griff nose-cone would probably be an irritation to the factory now I take your point about the pressures though and as it happens I felt comfortable on about 26-28 all-round. Rich...

You made the connection.... I didn't say anything just stated some disconnected facts!! No Neil is a good guy and tyre pressures are very much personal things because the tyres need to work well for you and that depends on the driving style and what the tyres are being asked to do.

I had an instructor with me who reckoned the Cerbera tyres were way too soft and that they should be around the 35-40 lb mark but it turned out that re raced Porsches. Higher pressures seem to suit them. I think the 10% figure is a good start as it is less likely to cause problems with using an incorrect absolute figure.

Steve

[shpub]

One problem with running low pressures especially on TVRs is that yes you get full tread width but you may find the footprint is hollow and the centre is not flat. In addition the problem of rolling the tyre off the rim is quite common because the lower pressure is not enough to help the tyre stay in place. Many of the different handling experienced with different makes are all to do with the sidewall strength and resistence to rolling. Can be made worse having smaller width rims. This was a major problem when I started sprinting in the standard class and I noticed I was wearing out the side lettering at times. IF I increased the pressure I could control the sidewall movement but the tyre ballooned and the grip went. Lowering the pressure improved the contact patch but started the sidewall wear. Solved the problem with a 2 inch wider rim, and lower profile tyres.

All this is in TVR land and may have no relevance to any other make! But it makes you think...

Steve

[Pete Cros]

I'll now throw another spanner in the works:
Driving on track in the wet using road tyres. Generally increase the pressure of the tyres. This opens out the tread pattern, and therefore shifts water faster. Using lower pressure road tyres in the wet will close the tread pattern and produce aquaplaning.

In the dry, multi pattern treads (i.e. lots of 'blocks' in the tread pattern) will result in 'squirming'. This is because as the tyre heats up, the 'blocks' start to give/move more.

Tyre pressures for track days are a can of worms. As I tried to hint at before, they isn't any hard and fast rule that you can follow.