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psi for tyres...

Gizmo73
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Gizmo73 Proficient

Gizmo73

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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 ??

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Edge Proficient

Edge

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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.

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Sydneykid Grand Master

Sydneykid

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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

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