Semi Slick Tyre Pressure Xr8 Ute

[Apes]

Hi Guys,

Im looking for tyre pressure recommendations for Semi Slick tyres running at QR.

My Ute is a turbo V8 XR8 making 520RWHP. I have bilstein allround, kings FG HD rear springs, 850LB spings at the front and a 27mm front bar.

I am running Kumho 710 (which is a full slick with two small cuts around the tyre) in the front a Pirelli PZero Corsa at the rear.

Tyre size is 245/40 R18. Any ideas lads???

[power_slide]

The tyre supplier would give you the best idea on preassures and how much they will change under heat,

There will also b more info on the khumo site

I would run bridgestone re55s all round on the ute if you have the cash

With that power I would want some soft rubber on the rear

[_John_]

I`d take a pump and guage to the track, ask around amongst the other punters and failing that just experiment.

Looking at the specs you should have a blast.

[Guest XR09]

Are you using strait air ? or a nitrogen mix. Or full nitro.

If it is a propper slick and just using air, I would start at about 36 cold in the front. If you are using a nitro mix then 38 cold. The rears are definately street and I think 36psi would be good as they have a stiffer sidewall to begin with and your don't have the weight in the back of a ute. If they are not getting the power down out of the corners go down 2 psi at a time. But remember it is a ute and they don't get it down as well as a sedan.

But yes definately check them out after you first four laps. I think that's what the sprint series is for rego'ed cars this year 4 laps. If the inner of the tire is scrubbing go up two psi. If it's the outer then down two.

[ScatterBrain]

When I was doing the sprints at QR last year I found that 36psi hot in the rear and 37psi hot in the front was spot on for me. The reason I was running higher pressure in the the front was because I wasn't running enough camber at the time.

Edited 03/01/11 12:14 AM by ScatterBrain

[Apes]

When I was doing the sprints at QR last year I found that 36psi hot in the rear and 37psi hot in the front was spot on for me. The reason I was running higher pressure in the the front was because I wasn't running enough camber at the time.

What type of semi slicks where you running??

Are you running more camber now?

[Apes]

I`d take a pump and guage to the track, ask around amongst the other punters and failing that just experiment.

Looking at the specs you should have a blast.

I have been doing the last three seasons using toyo 888's and yes it is great fun. I was hoping there was a experienced sprinter that uses the forums because I dont think I have got the tyre pressures right. It is quite difficult to get the correct setup with tyre and suspension combinations. Its frustrating as there is not to many people out there on the forums that do these events that want to share the information.

[Apes]

When I was doing the sprints at QR last year I found that 36psi hot in the rear and 37psi hot in the front was spot on for me. The reason I was running higher pressure in the the front was because I wasn't running enough camber at the time.

Can you confirm if your 6T is a ute or sedan? I noticed that you are running a sway bar in the rear. If it is a ute do you find the car over steering coming out of the corners?

[Apes]

Are you using strait air ? or a nitrogen mix. Or full nitro.

If it is a propper slick and just using air, I would start at about 36 cold in the front. If you are using a nitro mix then 38 cold. The rears are definately street and I think 36psi would be good as they have a stiffer sidewall to begin with and your don't have the weight in the back of a ute. If they are not getting the power down out of the corners go down 2 psi at a time. But remember it is a ute and they don't get it down as well as a sedan.

But yes definately check them out after you first four laps. I think that's what the sprint series is for rego'ed cars this year 4 laps. If the inner of the tire is scrubbing go up two psi. If it's the outer then down two.

I never really considered using nitrogen I did some research a few years ago and the conclusions where that for the cost there was not to many beneifts only more stable tyre pressures, but I will look into it again. The other set of semi slicks I have Pirelli Pzero (Corsa) and they are not street tyres. I did not rate them as high as the toyo 888's I run for a couple of seasons. My front two Corsa's are now screwed as I lost my ABS last time out and flat spotted them twice. Im trying the Kumho 710 as they rate really well in the US on there heavy cars and got them at a good price. I have reduced the front swar bar to 27mm which has helped amazingly with understeer. With the 30mm and 850lb front springs the understeer was terrible. Cant wait to go out on the 14th of Jan for the test day.. Thanks for your input with tyre pressure

[Tocchi]

I was using 36-38 PSI in my front Corsa's (235/40/R18) due to the heavier front end (xr8), was actually quite nice ONCE they got warmth in the front end.

the rears gripped well with 35 psi in them .. again, once warm

edit

you doing track work (eg: 1 warm up, 3 hot, 1 cool down) or motorkhana sprints that are sub 1 minute tracks?

Edited 03/01/11 04:08 AM by Tocchi