What Tyre pressure in Semi Slicks

[antnicuk]

I have just fitted some Toyo T888 semi slicks,   just wondered what sort of pressures people run with them. I  normally run about 28 - 30 on a road tyre like a good year eagle F1 so get some traction but i would have thought i could run higher on a soft tyre.

[royal]

I don\'t know the right answer but I always run at least 35psi on mine?

[alexb]

I run 32psi in my R888\'s.

Cheers,
Alex

[20B_boy]

I run 32psi in my R888\'s.

Hot or cold?

[alexb]

Pressure measured when cold.

Cheers,
Alex

[RotorHeid]

Buy a Hand Held Tyre Temperature Gauge,it\'s great tool.
32 psi for the road all around and ranges from 18-38psi  for rear/front for fun day!

[Mart160plus]

Where\'s the best place to get the tyres from, need some for the Ring ?

Ta,

Mart.

[TonyC]

If you are running these soft compound tyres you will need to run presures lower han normal.
Not sure why, but people always put too much air in these tyres.
Before the usually MRC disclaimers appear, I\'m talking about using these tyres on track not road.....

You wan\'t to start at a lower than normal presure as you need the tyres to heat up to work. as they heat up the presure increases. If you start of at 32psi, buy the time the tyres at at operating temp you will be somewhere like 37psi and the tyre contact patch will have shrunk.
you start lower,so that when they warm up they are at the correct presure. I would start off with them cold maybe 4 or 5 psi under the standard presures. There is an element of feel and checking in this. You will also need to \'read\' the tyre to see if it is overheating. Check for a blueish tinge to the rubber - that means i is over heating - depending where the tinge appears will mean doing diferent things to presure or camber.

also, when cold and low presure they flex more - this is great as you can work the tyre on the road and the rubber movement will make it warm up and increase in presure. So if you start low like that the tyre beings working sooner.
Also, by starting lower the tyre will stabilie during the track session, and won\'t \'go off\' before the session ends.

if is wet you won\'t get them as warm so you usually need to start off with around 2-3 psi more (cold) than on a warm day. They do work pretty well in the wet - but aquaplane horrifically if there are puddles. I\'ve raced in moonsoon (litteraly) conditions with these - you just need to be delicate. The rain was so heavy i couldn\'t see a car a few yards in front - I\'ve a great in car vid that shows how bad it can get.

You may find the edges of the tyre \'blue\' after a few sessions - this will be more than likley due to a lack of negative camber - these kind of race tyre love extra camber compared to a road tyre, you may need to dial in a degree or more of negative camber.

All of these is really tuned by tyre temps, presure readings, feel of the driver and lap times.

i\'ve used these types of tyre for several years in all sorts of track conditions.

[20B_boy]

I run about 27-28psi cold on R888s, just a couple of psi more and it doesnt feel any where near as glued when they are warm. I get the blue edges a bit but the car does a lot of motorway miles so I\'ve elected against messing about with geometry much. The other car will be more track focused so will be able to set it up a little moew aggressively.

Whatever, I\'d start low Ant and see how they feel...888s dont seem to take as much to get warm so you should be able to get a good feel of what works fairly quickly.

[alexb]

Cool, that was on the road btw. I\'ve got my first trackday with the car at Snetterton on Wednesday next week so will try lower pressures as suggested

Cheers,
Alex

[antnicuk]

I have started at 28 psi cold pressure.   It was a second hand set i was kindly given by Matt.  There isnt a lot of tread but just enough to get to the ring and back next week......  hopefully

Just playing a little bit on the road they didnt feel as good as i was hoping but they be more to do with my expectations.  I had eagle F1\'s which i have always loved.  Maybe i\'m not getting them warm enough.  I will play with pressures a little but i\'m reluctant to play with the camber as i will be back to road tyres when i come home.

[Mart160plus]

Where\'s the best place to get the tyres from, need some for the Ring ?

Ta,

Mart.

Nudge........, I\'m sure Santa Claus didn\'t deliver all of your tyres folks !

[20B_boy]

Just playing a little bit on the road they didnt feel as good as i was hoping but they be more to do with my expectations.

Strange, they *really* hang on at the Ring, even driving like a complete pleb a la me

[royal]

Bloody ell, wish I\'d known lol! looks like I need to lower the pressure substancially (sp). Funny I\'ve not been getting uneven wear though I don\'t think.

[AtomicRex]

I run 26psi in both my wets and slicks.

Heat soon gets in the tyres (Boyle\'s law) and what you don\'t want to be doing is running on a ball of solid rubber!  No compliance!

I used to have the problem with bikes on the track days....the manufactures recommend 36/42.....so on a track day thats what I would see.....although I wouldnt......it would be more like in excess of 50psi

Halfords sell cheap digital tyre gauges.....so best plan is to get one.  Personally I wouldn\'t bother with a cheap thermometer, the main reason for using a pyrometer is to check camber.  By looking for an even spread across the tyre, and then the only real way is to use a probe that actually goes into the tyre!