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Tyre pressures


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I have a track day coming up at Croft Circuit and wanted to know the exact pressure I should be running.

 

Loads of members are now running with 19" rims, so let me know what pressures you are currently running with.

 

My tyres are:

 

Falken 452's

245 x 35 x 19 fronts

275 x 30 x 19 rears

 

Cheers

Steve

Edited by Steve-300ZX
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Steve,

 

I used to run mine at:

 

Front: 235 x 35 x 19 @ 34psi

Rear: 265 x 30 x 19 @ 36psi

 

Gave me a good handling balance. Car's been off the road for a year now so probably have square tyres by now ...LOL! :)

 

I do seem to recall that maximum pressure ratings are now stamped into the sidewall of each tyre - have a look. Don't exceed those ratings.

 

Dan

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Tyre pressure is not affected by wheel size. So use the standard nissan recomended tyre pressure for stock wheels.

 

As for tyre pressure for track racing - difference of preference, lowering a couple of psi can improve grip at teh cost of wear, increasing a couple of psi will save wear.

Edited by Yowser
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As you have a good low profile sidewall you will be ok at the pressures Dan says,but remember that tyre pressure increases when they get hot on the track,so in reality the pressure will be cold 36 psi,hot around 42-44psi,if you find that after a run its a bit skittish drop them around 8psi to give you back the cold value,tho with your tyre size you should be ok,if its dry conditions.If you have fairly new tyres drop them down 10psi or more as the block tread will get very hot and the grip will be rubbish,to be honest all cars are different,especialy on track days,whats good for some will be not be for others,trial and error in most cases.The cars weight,geometry,handling,etc etc all come into the equation too.Looks like the Z should be well suited to Croft as its got 3 good straights and only a few twistys.Have fun :cool:

 

Tony

Edited by TonyC
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Unsure for track, but there was a few postings a few years back, which basically said add an extra 2psi per every inch in diameter you go above standard.

 

Barry

 

I remember that, but surely it's more about width and profile than wheel diameter ?

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I remember that, but surely it's more about width and profile than wheel diameter ?

 

I think you're right Andy. If memory serves me (and I'm having to dig very deep into my GCSE Physics time many, many moons ago), as volume decreases (ie lower profile tyres) then pressure must increase in order to support the same mass (ie weight of the car). So therefore it follows that if you drop the profile of the tyres you'll need to increase the tyre pressure in order to support the weight of the car.

 

I stand to be corrected.

 

Dan

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Technically when you go to a larger tyre with a larger contact patch, the pressure can actually be lowered because the weight of the car is now being transferred to the road via a greater area.

 

Also A larger tyre with lower side wall results in less air volume which means the pressures will increase faster under load than with a tyre that holds more volume.

 

The differences are minimal and not worth taking it account, and alterating tyre pressure on one vehicles is often more about driver preference.

Edited by Yowser
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