psi for tyres...

[Gizmo73]

Hi Guys...

Another embarassing noob question here.. :Oops:

Regarding tyres, does the psi required change depending on profile and size ??

For example, i have 235/45 on the front, and 265/35 on the rear (18 inch)..

Should they all equally be inflated same psi ?? Back harder ?? Front harder ??

[Genesis®]

this has been covered many times. use keywords like 'psi' in the search.

i got 36 in front and 34 in back. reason being the extra 2 psi in front is becos of the weight of the engine.

hope that helps

glenn

[Gizmo73]

Hi Glenn...

Thanks for that - i did a search, and couldnt find it...seems like it was because i searched on "psi", and got too many turbo threads !!!

Added "tyre", and found what you were referring to....thanks..

[Sumo]

I was told to run 38 PSI in my s03's by the bridgy fella's - So I do

Sumo

[slip]

you can adjust handling characteristics too, and compensate for different tyre sizes as you mentioned. I run 40 front 38 rear, hard driven car. having a couple of psi more in the front helps reduce understeer generally.

[Edge]

in r33 it isn't understeer you are worried about though

I run 43 psi all round. Although lower rear pressure will give you better traction for accelerating. Just go as high as traction under hard acceleration permits with your tyres.

Once you go hard enough you may get the occasional chirp as it looses traction over tiny road bumps when accellerating from the lights.

[unwritten law]

goddam 43 psi??? what is the max psi the tyre can run?? i am running 33 at the moment.. i am thinking of upping it to around 35 tho...

[Genesis®]

i agree. the air inside will expand a couple of psi more, which means that you are running with 4 tyres with max air limit....

[Edge]

goddam 43 psi??? what is the max psi the tyre can run?? i am running 33 at the moment.. i am thinking of upping it to around 35 tho...

51 psi is what it says on the sidewall

[Sydneykid]

Hi guys, we run 25 psi (cold) in the 235/40/17 Yokohama A032R's, that goes up to 34 psi when they get hot (after 1 lap). Any more pressure than that and they start to overheat in spots as (being radials) the higher pressure doesn't let them follow the track surface. Since only some parts touch, they get hot and blister.

An extreme example, as the compound is soft, but the same principle applies to any tyre. Too high a pressure reduces the tyres ability to follow the road surface. I would strongly suggest that any Skyline with appropriate suspension geometry, would need tyre pressures in the 28 to 34 psi range on the road. For the track, unless the geometry has been set up for it, adding 5 to 10 psi helps keep the tyre more upright under the extreme side loading you get on the circuit. For the drags I would suggest 5 to 10 psi less would aid the traction for launch.

Hope that helps