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Discussion Starter · #1 ·
i'm moving to 18" wheels and can't decide what tire size to use.
the wheels are OZ ALLEGGERITA HLT 8.5"/10".

today i'm on stock 19" with 235/35 - 265/35 tyres, cambers are maxed at ~1.5-1.8 all around.
with this setup the balance is quite good.

for 18" i would like to get a bit more grip by moving to 255/285 tires.
for the front 255/35 size looks pretty close to OEM size.

the problem with the 285 for the rears - all good tyres are at 285/30 but this looks way too small comparing to OEM size.

so please advise what sizes you usually run on 18".
:thanks:
 

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235/40ZR18 - 25.4
285/35ZR18 - 25.9
Michelin Super Sports
 

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Discussion Starter · #4 · (Edited)
yes, the 285/35 looks like a good fit.
but the only tyres i see in this size are:
- PSS, which i currently have and want a stickier tyre
- RS3, which are great but with less than 2 degr camber they will be shot very very quickly

285/30 are vary too much from the stock size.
 

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I'm running 255/35-18 & 275/35-18 Dunlop ZII Star Spec on stock sized OZ wheels (8x18 & 9.5x18), which is working great with no rubbing. I chose this combination as it's identical to OEM rake and maintains the right circumference ratio; drops the car a few mm, too. With just a front GT3 swaybar and no other suspension mods, the car balance is amazing at the limit (autocross & time trial). These tires should work even better on the slightly wider rims you're running.
 

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Discussion Starter · #6 ·
Steve, thx for the input.
i didn't think about raking:wall:. this is a good point.

but - the tire calculator shows me that 255/35-18 has 6mm smaller radius than stock 235/35-19 and rear 275/35-18 has 9mm smaller radius over stock 265/35-19.
so actually the raking changes a bit.
 

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Sorry, *almost* identical to OEM rake. So long as the circumference changes consistently front:rear, PSM/ABS won't react adversely. It's looking at the difference in speed, not actual speed. If you think about it, 3mm is smaller than the change you'll see just going from old tires to new and well within tolerance.
 

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Discussion Starter · #8 ·
If you think about it, 3mm is smaller than the change you'll see just going from old tires to new and well within tolerance.
:hilarious:

this is so right...
 

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i'm moving to 18" wheels and can't decide what tire size to use.
the wheels are OZ ALLEGGERITA HLT 8.5"/10".

today i'm on stock 19" with 235/35 - 265/35 tyres, cambers are maxed at ~1.5-1.8 all around.
with this setup the balance is quite good.

for 18" i would like to get a bit more grip by moving to 255/285 tires.
for the front 255/35 size looks pretty close to OEM size.

the problem with the 285 for the rears - all good tyres are at 285/30 but this looks way too small comparing to OEM size.

so please advise what sizes you usually run on 18".
:thanks:
For the wheel specs that you listed 18x8.5 and 18x10:

245/40/18
275/40/18

IMHO: A stock powered 987.2 doesn't need a 285 rear tire unless you are looking for a car that can't break the rear end loose at all.
I can barely break loose the rear end of my track prepped Cayman R with 275 street tires in the dry, let alone R-comps.

A 987.2 turns perfectly fine with a 245 front tire, no need to go for a 255 tire unless you are doing wheel 2 wheel racing at 9.5~10/10th all the time and want to have tires that don't overheat/go off quickly.

It all comes down to the application, in other words what you plan to do with the car. Auto-x, track days, time-trials, racing? Tires are only part of the equation and not the be all in the handling department when chasing for grip.
 

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For the wheel specs that you listed 18x8.5 and 18x10:

245/40/18
275/40/18

IMHO: A stock powered 987.2 doesn't need a 285 rear tire unless you are looking for a car that can't break the rear end loose at all.
I can barely break loose the rear end of my track prepped Cayman R with 275 street tires in the dry, let alone R-comps.

A 987.2 turns perfectly fine with a 245 front tire, no need to go for a 255 tire unless you are doing wheel 2 wheel racing at 9.5~10/10th all the time and want to have tires that don't overheat/go off quickly.

It all comes down to the application, in other words what you plan to do with the car. Auto-x, track days, time-trials, racing? Tires are only part of the equation and not the be all in the handling department when chasing for grip.
I agree with you save for the breaking the tires loose. I have run 888's with a 55/85 setup and I could easily get the car to break the tires loose. Granted, I've got a full suspension and loads of adjustability - but even with those tires the car could be setup to be squirrelly. Like you said though, this was also based on my setup and how I had it dialed in.

My recco if you are driving to the track would be the 888's. They are "good" in the rain, and very predictable. Not as good in terms of heat cycles as the NT01's, but I wouldn't drive those to the track anyway. Just set your expectations - they aren't a street tire for day to day use and will HC out, so if you do more than 5 - 7 days a year expect to be buying multiple sets.
 

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Discussion Starter · #11 · (Edited)
For the wheel specs that you listed 18x8.5 and 18x10:

245/40/18
275/40/18
the tires i see in those sizes are only R888, NT01 and Bridgestone RE-11.
anything else that you guys aware about?

i don't really want to go for r888 and nt01 as they push me to the "unlimited" category in our local events.
this is where are GTRs, cars with Hoosiers and other crazy cars are.

i'm thinking to try RS3 with 255/35-18 and 285/35-18.
just not sure that 285/35-18 fits with no rubbing:crazy:
 

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the tires i see in those sizes are only R888, NT01 and Bridgestone RE-11.
anything else that you guys aware about?

i don't really want to go for r888 and nt01 as they push me to the "unlimited" category in our local events.
this is where are GTRs, cars with Hoosiers and other crazy cars are.

i'm thinking to try RS3 with 255/35-18 and 285/35-18.
just not sure that 285/35-18 fits with no rubbing:crazy:
Hmm.. Since you mention categories it seems that you are referring to Auto-X.

NT-05's are available in 245/40/18 as well as 275/40/18 Treadwear rating of 200 IIRC (Not sure if they are available in your country though)

RS3 are probably the Hankook's? Have not used them before so can't comment on those...
 

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Discussion Starter · #13 ·
it seems that i won't be able to get locally RS3 in those sizes.
so to keep spendings down i started to think to keep 19" wheels but to move from PSS to Pilot Sport Cup 2.
same size as i have now - 245/35/19 and 275/35/19.
 

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Hankook R-S3 have a weak sidewall and don't work as well on heavier soft sprung cars like ours. Chris Cox won SS at nationals last year with his GT3 on Yokos, and ZII* works really well. Rival S is supposed to be out in the next month or so and could be faster still; no telling yet. All should be faster than MPSS, though.
 

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I have a set of Cayman S wheels for my Cayman R...does anyone use these for the track? If so, what size tires...I'm looking at RS3 or RE11.
 

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I have a set of Cayman S wheels for my Cayman R...does anyone use these for the track? If so, what size tires...I'm looking at RS3 or RE11.
On my Cayman R I run RS3 in the stock CS sizes: 235/40-18 and 265/40-18. I like the RS-3s. Also consider the Yokohama AD08R although they are higher price. In R compounds the most commonly used tire seems to be the NT-01 in 245/40-18 and 275/40-18. Good luck.
 

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On my Cayman R I run RS3 in the stock CS sizes: 235/40-18 and 265/40-18. I like the RS-3s. Also consider the Yokohama AD08R although they are higher price. In R compounds the most commonly used tire seems to be the NT-01 in 245/40-18 and 275/40-18. Good luck.
Thank you!!!
 
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