S2 Tyre Pressures

xtreme · Post by **xtreme** » Fri Jun 16, 2006 10:37 am

Help!

My rear AO48's on S2 exige are wearing badly in the middle - suggesting my tyres are overinflated. Have always tried to set them as per guidance in the handbook!

So, anyone advise what the best pressure for an S2 exige running AO48's on the road and track are?

Would also appreciate some guidance from the old hands - what pressure should I be aiming for cold / hot for best performance???

Thanks - and I have tried a search !

Barrie

Edit! Sorry I should have made it clearer above - I am guessing that I should run at different pressures for road and for track?

PS Next question is where to buy tyres!!!

Post by **Shug** » Fri Jun 16, 2006 10:40 am

Over to the S2 Exige owners... You'll find them running lower cold pressures on track, as the air in the tyres heats up and expands.

The book pressures may also be a little generous, to cater for the drivers who only use it in town, etc.

Tom · Post by **Tom** » Fri Jun 16, 2006 10:46 am

Ed had exact same prob at EF. practically bald across the centres at the end of the day. And i think he only had 28psi ish cold. MMC (or their contractor) put 33psi in his new set of rears

.

Uldis · Post by **Uldis** » Fri Jun 16, 2006 11:04 am

It's a common mistake, and it can get expensive.
I think it's just a way for Lotus to make more money from tyres.

Depends on track use, but look towards runing around 24 psi operating pressure.
This means cold they should be set to something like 23F-25R, hot, well try to be around that are.
This means that if you like to be out on track for long stints like me (I like to go out for an hour at a time) you keep on adjusting the pressures to read something like 24 hot and by next morning when you measure them cold they have been down to 17 psi! (which I don't recommend for the road but gives you an idea)

So there you go, quick recipy.

Now, if you want to be more precise, get a pyrometer and measure the outside, middle and inside of the tyre and see the temp pattern. Hotter means it's working more, so if the middle is hotter than the outsides,let off pressure and vice versa.

You'll end up in the same bracket but would be more precise.

Andy G · Post by **Andy G** » Fri Jun 16, 2006 12:08 pm

i've been using mine at 22F, and 24R

The wear in the middle is normally over infaltion and can reduce the tyres life dramtically.
There was a US owner who managed to get 5-600 miles out of his first set

Tom · Post by **Tom** » Fri Jun 16, 2006 12:11 pm

Andy G wrote:i've been using mine at 22F, and 24R

The wear in the middle is normally over infaltion and can reduce the tyres life dramtically.
There was a US owner who managed to get 5-600 miles out of his first set

erk...

i read that as 5-6000 the first time.... blimey.

mac · Post by **mac** » Fri Jun 16, 2006 12:22 pm

Barrie,

I run mine at 24f 26r at a warm temp. By warm I mean by the time it takes me to drive at a legal limit from my house in Blantyre to the Q8 petrol station at Bowtrees Round about.

I would try 22.5f 24r from cold and see how that goes. The book is WAY off the mark.

Mac

Post by ed » Fri Jun 16, 2006 12:28 pm

i currently run 24 fronts and 25 rear cold for normal road use (stole that from ali c). for track i normally drop them a couple of psi each and perhaps a little more for the front left and it gets a hammering, especially at KH. Mac runs as above for his 48s on track and his front still have 4mm on them after around 6000 miles

am thinking that i may still be a touch too high.....

Brian J · Post by **Brian J** » Fri Jun 16, 2006 12:53 pm

Generally agree - I run a pound or two higher 25/26 on S2 Exige (heavier than Uldis' S1) as too low makes it heavy around town and seems less precise at speed when not on track. Everyone seems to have their own magic number

On track, just check regularly and, as Uldis, says, drop them down to your chosen pressures as they heat up. Otherwise, they can easily go well over 30 which will destroy the handling .......and the tyres.

Interestingly, at Donington I asked the Lotus test drivers what they did - they said they just left them alone at Handbook pressures - but they expected to use a set in one day.