[Rube1966]

Did a little homework, seems a 255 is a 1/2 inch wider than stock (245/40/18), but only a fraction if an inch of a taller sidewall. At 55 mph, the speedo is only off by 1 mph.

Seems like this would be a great replacement tire size in order to give a little more tire to the ground without screwing up the total tire diameter size.

my 2 cents.

[battlecat]

if you autocross 255 will bump you out of street touring classes.

[bigd]

from what I understand, fatter tires (on the same rim) can give you more overall grip because of increased contact patch, but it can feel less responsive. a narrower tire (on the same rim) essentially preloads the sidewalls, making the tire respond a bit quicker. I believe fatter tires will also overheat easier if driven aggressively (like on a track, etc) from the carcass moving and squishing around more.

[CharcoalSTI]

I am more than happy with mine.

[altaic]

I'm running 265/35R18 on offset 55 wheels

You'll probably want to run a bit higher tire pressures to avoid sidewall flex. Use a temp gun to make sure the center's not ballooning out and getting hotter than the rest of the tire.

[waktasz]

That's hardly a change in size at all. They will be fine.

[ploney]

255-35-18 here, no problems with em.

[impressive]

im running 255/40/18 ad 07 i like it very much fits the fender perfectly with my advan rs...

[caveguru]

Originally Posted by Rube1966

Did a little homework, seems a 255 is a 1/2 inch wider than stock (245/40/18), but only a fraction if an inch of a taller sidewall. At 55 mph, the speedo is only off by 1 mph.

Seems like this would be a great replacement tire size in order to give a little more tire to the ground without screwing up the total tire diameter size.

my 2 cents.

Generally, I think most people prefer to go smaller on overall tire diameter to improve wheel to fender clearance and to get a slight gear-down. I am however looking at this exact size because it is the only option for the Yoko Advan AD07 in 255 width and 18 diameter. On the '08's with 275/35/18's on +45 rims, the front wheels are very close to the fender liner. No rub yet, but with certain wheel/tire options this could be problem. For example, I'm looking at some +35 offset rims, which will put the shoulder of this tire in the same spot as my 275's, except that the 255/40/18 is larger diameter, so I may get some rubbing.

Frank

[impressive]

Originally Posted by caveguru

Generally, I think most people prefer to go smaller on overall tire diameter to improve wheel to fender clearance and to get a slight gear-down. I am however looking at this exact size because it is the only option for the Yoko Advan AD07 in 255 width and 18 diameter. On the '08's with 275/35/18's on +45 rims, the front wheels are very close to the fender liner. No rub yet, but with certain wheel/tire options this could be problem. For example, I'm looking at some +35 offset rims, which will put the shoulder of this tire in the same spot as my 275's, except that the 255/40/18 is larger diameter, so I may get some rubbing.

Frank

very slight rubbing in the rear with stock suspension after coilovers and minor fender roll no rubbing at all my wheel is offset 45 wheel and tire is almost sticking out of the fender.

[caveguru]

Originally Posted by impressive

very slight rubbing in the rear with stock suspension after coilovers and minor fender roll no rubbing at all my wheel is offset 45 wheel and tire is almost sticking out of the fender.

you're running them on +45 rims, so you won't have any problems. On the '08's, the problem is at 1/2 lock on the front edge of the outside wheel. Less offset causes the wheel to be further forward at this point which is why it almost kisses the fender liner. I also have the WL ALK kit, which pushes the wheels maybe 1/8"-1/4" further forward than stock, and I bet I'm ~1/4" away from the fender liner. Not nearly the challenges faced on older cars with really big tires, but just fyi for the OP.

Frank

[InfernoSTi]

18x9.5 +45 TR wheels with 255/40/18 (Azenis RT-615). Would like to go to a 265/35 or a 275/35 with the next purchase. They fit on the stock set up but were tall so I did a minor finder roll in the rear. Tiny clearance at 1/2 turn at the front but no rub.

Vorshlag- powered by SmugMug

[Subie 2.5 STI]

very nice.

[sleepyhead]

Originally Posted by Rube1966

Did a little homework, seems a 255 is a 1/2 inch wider than stock (245/40/18), but only a fraction if an inch of a taller sidewall. At 55 mph, the speedo is only off by 1 mph.

Seems like this would be a great replacement tire size in order to give a little more tire to the ground without screwing up the total tire diameter size.

my 2 cents.

Are you putting these tires on the stock rim? I'm curious because I am considering putting on 255/40/18 on the stock non-bbs rims and wanted to make sure I would not have any clearance issues. Anyone else chime in on this?

[CharcoalSTI]

Depends how wide the rim is in comparison to the tire. Otherwise its like wearing your dads shoes, as in like when you were 5.