Running 27/68-18 Slicks?

[savant]

Hi Guys,

We are looking at running Michelin 27/68-18 (682mm high) slicks on all four corners. We can get these cheap second hand ex-Porsche cup (about $250/set).

Will these be too tall? I gather the V-Spec's ran 225/50-17's which are about a 657mm rolling diameter, so we would only be about 25mm oversize.

I assume the width is not such an issue, we are looking at getting a set of Enkei RPF1's in 18x10.5 ET18.

We are currently running 24/625-17's which are obviously not a problem. We could also get 24/65-18's (also ex Porsche cup) and get some 9.5" wheels but would rather run the wider setup.

Cheers for your help!

[blackrex]

Make sure that they are not a specific construction to cope with the "unique" layout of the Porsche Cup Cars, I am aware that the euro series do have their own spec Michelins, I'm not sure if it is the same here.

[savant]

Make sure that they are not a specific construction to cope with the "unique" layout of the Porsche Cup Cars, I am aware that the euro series do have their own spec Michelins, I'm not sure if it is the same here.

Good point, it was suggested we don't run the fronts (the 24/65-18's) as this is the light end on the Porsches.

[R32 Stuart]

Hi Guys,

We are looking at running Michelin 27/68-18 (682mm high) slicks on all four corners. We can get these cheap second hand ex-Porsche cup (about $250/set).

Will these be too tall? I gather the V-Spec's ran 225/50-17's which are about a 657mm rolling diameter, so we would only be about 25mm oversize.

I assume the width is not such an issue, we are looking at getting a set of Enkei RPF1's in 18x10.5 ET18.

We are currently running 24/625-17's which are obviously not a problem. We could also get 24/65-18's (also ex Porsche cup) and get some 9.5" wheels but would rather run the wider setup.

Cheers for your help!

R35 Duncan ran the Michelin's, new and used - had some concerns on heat cycles etc with some.

I ran Dunlop 280x 680 x 18s on R33 you will have issues with inner guard plastics front and rear, fuel filler plastics foul, if you are lucky enough to get some grippy ones even not running spacers stock up on wheel bearings.

The 25mm oversize will give you about 1/2 a gear difference - so depending on horse power, torque and the track you are running - something to keep in mind

Cheers

[LSX-438]

These work great for r35' check the compound. S7, S8 or S9. If buying 2nd hand, S9's are best (harder compound, but last longer) with S7's being softest (only lasting a few heat cycles)

[savant]

Sorry, should have put in the important information - The car is an R32 GTR.

[T04GTR]

get the 27-65-18. front tyre for gt3-rsr. also used on a few production sport cars too.

ive got a couple stacking up in my garage. (used to work for the utes and lots left after each meeting...)

they do fit under my missus r33 gtst. so 32 gtr wouldnt be an issue. but a wheel with +22 or greater will help fitment. (guard clearance) z32 wheels with a custom bolton spacer thickness would be the easiest option

[RS581]

Im pretty sure the top of the tire will hit the top arm

[jazzy_j]

They will fit. However you will have to remove the inner wheel arch guards and the factory blow off valves if you still have them. The car will ride hi but it's not too much of an issue if you set the car up right.

Last time I saw the Windfield GTR at eastern creek it was running these exact tyres.

[OLLIE_NZ]

They will fit. However you will have to remove the inner wheel arch guards and the factory blow off valves if you still have them. The car will ride hi but it's not too much of an issue if you set the car up right.

Last time I saw the Windfield GTR at eastern creek it was running these exact tyres.

Thanks Jay, (I co-own the car with savant/ Willie)

If that's all it will take then it's worth it for the price saving on buying slicks alone.

So you reckon, just removing the plastic wheel arch liners is enough, no guard rolling needed?

Does anyone know what dimension the tyres were on the Bathrust GTRs?

Cheers mate,

Ollie.

[jazzy_j]

Yeah I think you will have to roll the guards. Ours were already rolled and it was awhile ago that we tried them so I can't remember exactly how close they were.