Tyre Pressures

[powelly]

I can't find many posts on the topic and I'm off to Oulton Park tomorrow :-))))

On my Griff, at a track day I've followed usual advice to increase pressures by @ 2lb each tyre. During the day, the pressure increase as the tyres heat up, but the outside obviously gets hotter and hence higher pressure than the inside..

Do I need to try and equalise this by running the outsides lower... or should I just shut up and keep my mind on the road????

Thanks

powelly

[shpub]

I would keep your eyes on the road. Tis only a track day. You are not racing just practising your roadcraft skills.

[adrianr]

I usually do a visual inspection of the tyres after each session and one or two hot pressure checks during the day once I've got up to speed. Doesn't take long and worth it for peace of mind and tyre longevity.

I've seen racers set cars up with different cold pressures in each wheel, e.g. 16/17/18/19 going round the car clockwise, but this is OTT for track day stuff, I'm mainly guarding against anything being drastically overheated or over/under inflated.

AdrianR

[washy]

I had my car set up by a very experienced race engineer/driver (Tuscan's, GT's etc) and he set my Cerbera up to 34psi hot all round at Mallory Park. That was after tweaking alignment and measuring tyre temperatures. In order to get them at that pressure hot the cold pressures vary between each corner and do need adjustment from circuit to circuit and session to session. As has been said you're not out there to race and get best lap times but getting the pressures right makes all the difference to the feel of the car and also helps keep the tyres from overheating so quick.

Hope this helps.
Washy

[powelly]

Cheers guys, I think washy hit my point on the head, anything to improve the balance of the griff will help.

I guess I'll give it a try by reducing the outside pressures when hot a little, whist remembering to enjoy myself and not take things too seriously of course!

[oldtimer]

I run a Porsche 911 and the advice I was given was to set pressures 2psi lower all round when on track ! I think this assumes they will run hotter therefore at higher pressure on track than normal driving.
However, here's my experience after several track days including Oulton - which has at least 3 hard braking points from high speed to low speed which heat the wheels up. If you are running road tyres then check pressures after each session and let air out so that 'hot' reading is at manufacturers ( cold) recommendation. EG 36 psi all round, keep resetting to this , usually the lhs tyres get hotter and need more let out. After 3 sessions usually stabilises, intent is to keep pressures balanced so this does not have effect on the handling.
I also run my hand across the tread to sense any temperature hotspots. EG if feels much hotter in centre of tread this is sure sign you are running over -inflated, if hot on shoulders then maybe underinflated.Should feel evenly hot across tread.
Tyres usually stay hot for journey home but you may need to top the air up once they have cooled off.

[Stig]

Just enjoy yourself and don't smack the armco!

Oulton is a fantastic circuit, but can bite. Take care through Lodge as it can spit you into the inner tyre wall in an instant.

Tip. As you crest the ridge at the top, apply a little counter steer (ie. steer AWAY from the corner), this should help keep things straight as the back end goes light.

Have fun.

[Leadfoot]

So you moved "oop nerth" then mate???

[powelly]

Oh yes, back home to the rich and pleasant land that is Cheshire....

Great thing about new location - Oulton is 20mins away, not 2.5hrs like Silverstone!!!!

[beano500]

And not gone for that T350 yet? The Griff is too good to part with isn't it!

[powelly]

far too good... for the moment.. I do think the only way to go for a track day is a caterham/westfield though, I hate to mention those names on this forum - sorry..