R32 Tyre Diameter

[mattie4270]

Hi guys just after some opinions from people who have done this.Now the story is a have an R32 GTR which i mainly use for 1000m airstrip time trials.The car has 1000hp and currently can run over 300kmph but the gearbox which is H pattern with a giken 1-3 gearset just doesnt want to shift fast at 9500rpm,poor thing,lol.So im in the process of ordering an OS88 but cant decided on which ratio.Im currently running 265 RSRs on R34 GTR rims which are about 24.4inches tall.Its pulling about 305kmph through the traps with the stock top gear(0.752) at about 9000rpm,so its close to maxed out.Now the plan is to run MT street radials 265s which have a diameter of 26.5 inch which will work perfect with the stock OS88 top gear(0.852).My question is will these fit diameter wise or will they touch the plastic inner guards?If they dont fit then i will lean towards a set of 265 R888s which are about 25.4inches tall and order the OS88 with the 0.75 top gear.So basically has anyone on here ran 18inch MTs 265s with stock inner guards?Any advice would be appreciated.

[GTSBoy]

You don't want to take a wheel off and do the measurement yourself?

[mattie4270]

You don't want to take a wheel off and do the measurement yourself?

The only way to measure is to dummy fit some tyres if i can find some worn out ones someone doesnt want,but having trouble locating some so thought i would ask if anyone has previously run this size with success.Just didnt want to go blow close to $2000 and find they hit the inner guard,anyhow see what happens.

[GTSBoy]

The only way to measure is to dummy fit some tyres if i can find some worn out ones someone doesnt want,but having trouble locating some so thought i would ask if anyone has previously run this size with success.Just didnt want to go blow close to $2000 and find they hit the inner guard,anyhow see what happens.

Are you sure that's the only way?

So what about cutting a disc of cardboard that is the right OD of the tyre you want to run, chucking it into the wheel arch and seeing if it clear shit or rubs shit?

[mattie4270]

No good doing unless the suspension is compressed to where it sits while driving,plus it will move up and down over bumps.Also need to do some full lock tests,so your method may give me a bit of an idea but wont gurantee all is good.Only way is to do a proper test with a tyre fitted or talk to someone that has run this size on this car already.Thanks for the idea but.

[KiwiRS4T]

Or just cut a length of wood 26.5 in long and hold it against your rotor as you turn it around.

And do you really need those inner guards?

[GTSBoy]

Or just cut a length of wood 26.5 in long and hold it against your rotor as you turn it around.

And do you really need those inner guards?

Standing kilometre, so he may well like the air flow control, but makes me wonder if he needs to turn the wheel very far.

[mattie4270]

Standing kilometre, so he may well like the air flow control, but makes me wonder if he needs to turn the wheel very far.

True dont have to turn the steering wheel much,or thats the plan anyhow.After chatting to a few drag guys seems like they JUST fit so think i will just bite the bullet and take it on.See if we can crack the 200mph/322kmph mark this year with the new sequential box.