Track tyre pressures on the AO48's

What is the received wisdom on this subject? In the past I reckon I ve ended up with over inflated tyres once they’ve heated up …so do you readjust once hot in the pits and to what pressures?


Adrian

I’m no expert on this, but I think you are right about them getting over inflated on a hot track - the wear seems more in the middle of the tyres. I took mine down to about 27psi at Croft on Sunday which seemed to do the trick, but Jamie who was also there in his S2 had them quite a bit lower still. Not sure what the optimum pressure would be though - I guess it would vary depending on the weather and track surface.

Mark

I run my A048’s at 18 psi on the front and 20psi on the rear. They wear perfectly at this.

Sean…

Depending on the day, it changes, but look for 23 psi hot all around.
This has worked out for me about 19F-17R , but changes depending on teh driver.

Start by 20 all around and measure after the sessions, letting air go until you get to 24 hot all around. That’s a safe bet.

I run my A048’s at 18 psi on the front and 20psi on the rear. They wear perfectly at this.

Sean…

I assume that’s hot Sean?

Ian

I was running 23/25 hot at Croft seemed to do the job

Thanks for the replies lads - just got in from work late.

Another thing, the crazing you get on the surfaace of the tyre after a hard track day really affects grip badly on th eroad afterwards I find until it wears throught to virgin rubber again - I guess it is rubber thats been virtually melted then has hardened but changed in properties giving less grip?

The ‘crazing’ you are talking about is just pickup. Ie loose rubber that is lying on the track which attatches itself to your hot tyres.

On tyre pressures… there are an aweful lot of variables here but the trick is to lern hoe to read the tyres. As a start poin try running the manufacturers recommended pressure when the tyre is hot.

One of these is on my Christmas list. Anybody used one? Seems good value (never thought I’d say that about something from Demon!).

The idea being that you find a pressure that gives a consistent temp across the width of the tyre.

Ian

I ran 26 hot all round at Donnington which worked well.

One of these is on my Christmas list.

[image]http://www.demon-tweeks.co.uk/resources/images/detail/MPLMH1.jpg[/image]

A non-contact pocket sized unit - invaluable for assessing the temperature of tyres, radiators, oil tanks, sumps, gearboxes and differentials etc. Simply point and press - quick response and accurate. Measures -20deg to +220deg C, switchable for deg C/ deg F. Battery life approx 40 hours, auto power off facility. Size: 110 x 45 x 25mm. Weight: 42gms. �29.75 (exc VAT) from Demon Tweeks

I have exactly that one.

Perfect!

I have exactly that one.

Perfect!

Looking at the price range on Demon Tweeks this does seem an extremely good price - the only negative thing I could think of is that it is maybe too cheap, ie, unreliable or inaccurate - Uldis, you says its perfect - can you expand?

Perhaps it does not matter if it reads inaccurately, as you are only bothered about the relative range across the tyre rather than the absolute temperature.

I have been after one myself also and so you may well have dug out a good un.

It’s cheaper than others only because of the range of temps it measures.
Most expensive pyrometers are so because they can read really hot temps, up to around 400 DegC.
This one tops out (IIRC) around 120 DegC, plenty good to measure tyre temps, but not good enough for disks or exhaust let’s say.

It’s very accurate and the resolution is .1 DegC
It’s also the smallest I’ve seen.
Perfect for having in your pocket and measure the tyre temp after every stint !

Cheers Uldis - off to order one now…

Did you get it from the ‘thieves’ Uldis? Or somewhere cheaper?

Ian

Demon Thieves.

Note that the �29 on Demon Theives website baloons to �43 once you’ve added VAT + POSTAGE + VAT on the POSTAGE

Didn’t stop me ordering one… but thought you should know

Didn’t stop me ordering one

Did stop me - I think I’ll have a surf and then if I cant beat the price will wait until Im in that neck of the woods and call in - the postage cost is right up there with the ebay scammers

Another option? Sub �20 (but…with perhaps a slight difficulty!)? - see here

Ian