Track Day Tyre Pressures?

[SimonKD]

Hi All

What is the general rule of thumb for altering your tyre pressures for track days.
I'm running Toyo Proxes, usual sizes for spiders and just wondered what benefits are to be had by changing the pressures.

Regards
Simon

[blackiepaul]

A sag is 24 all round and I would guess as your car is a simular size and weight that it would be there or there abouts.

As the tyres heat up during the day keep checking them and bringing them back down to 24, make sure you pump them back up the next day.

If you do not then the back of the car will start to have a mind of its own as they will be too high and the contact patch on the road will reduce giving you less traction.

[SimonKD]

Hi Paul

Thanks for that, I'll remember to bring my digital presure gauge to keep a check on them.
By how much would they rise approx once the tyres were well warm after a few laps?

Regards
Simon

[Tanguero]

Use a cheap IR thermometer to measure the temperature across the tyre - adjust the pressure to keep an even gradient. ie middle hotter than the sides - lower the pressure. Sides hotter than the middle - raise the pressure.

You can pick thermometers up from Maplins for a few quid - they frequently have them on offer.

[Dave 500]

Tanguero said:

You can pick thermometers up from Maplins for a few quid - they frequently have them on offer.

Are they any good?

[blackiepaul]

SimonKD said:

Hi Paul

Thanks for that, I'll remember to bring my digital presure gauge to keep a check on them.
By how much would they rise approx once the tyres were well warm after a few laps?

Regards
Simon

Hi Simon,

It is going to be down to how your drive and you will notice one side will get hotter than the other due to the amount of left or right hand corners you have on the track you will be on.

It sounds like it might be your first time on track or at least on 888's. Don't go to mad, they are good tyres and the grip is great, I agree with the temp of the tyres across the tyre width but I never do that and have not come into any problems yet - I am into track days but do not race though the team that built the car do and when they have driven it they don't either.

Measure them before you leave and you will notice they will go up just on your journey so take them down, do your sighting laps as well as a few more and come in and measure. You will then need to keep a eye on them every 20 or 30 minute session of you saty out that long.

Enjoy.

Paul......

[Tanguero]

Dave 500 said:

Tanguero said:

You can pick thermometers up from Maplins for a few quid - they frequently have them on offer.

Are they any good?

They do a couple of different ones - if you get the more sensitive model it works really well. I think I paid less than £20 for mine and it does the job a treat.

[jesfirth]

proxys have softish side walls so you want a bit more pressure in them than a b list tyre. the reason you need pressure is to reduce the side wall flex and tyre roll in the corners which will affect the contact patch. i would ty 26 as a starter and take it back from there.

[SimonKD]

Thanks for the input people.
I failed to mention the tyres are Toyo Proxes T1R's but I will keep an eye on the pressures.

Regards
Simon

[Mr Completely]

jesfirth said:

proxys have softish side walls so you want a bit more pressure in them than a b list tyre. the reason you need pressure is to reduce the side wall flex and tyre roll in the corners which will affect the contact patch. i would ty 26 as a starter and take it back from there.

There are people who know a lot more on here than I do

BUT

I upped my proxies for my first Track Day after reading comments on here and the car was all over the place.

IMHO go to a tyre fitter, get the air swapped for Nitrogen (2 quid a wheel at Micheldever) and run them at standard pressure.

All you have to worry about then is the tyre surface turning to chewing gum after 5 laps

[RichB]

Mr Completely said:

IMHO go to a tyre fitter, get the air swapped for Nitrogen

That old chestnut!

[cirvy]

I use 26psi with 888s & it's fine on most tracks