275/40/18 bfg kds on my stock 03 rays track wheels with no problems. launches much better-way more grip for the strip.

 

Those are only 18x8" too, aren't they? I was expecting a more pronounced bulge.

 

Actually stock 2003-2005 rays track wheels are 8.5 in the rear. 8.0 in the front.

 

+1

I bought the same rims for my '03. I really wanted to go 275, but i figured it'd bulge too much and be unsafe. Guess i'm gonna start shopping around Anyone know if the '06 front and rear rims are the same width?? Thanks!

 

I know that. I have them. The picture I quoted was the 2005 35th and 2006-2007 stock 18" rim. Thats what I was referring to. I don't remember if those rears are 8" or 8.5".

 

'06 stock rims are 8.5" in the rear. i just put 255/40 on the rears and now i know i probably should of went up to 265/40. but even 255 look pretty good.

 

stock 06 sizes are 8 front 8.5 rears

 

i run pirelli pzero nero m&s 245/40/18 in front and 275/40/18 in rear on my stock 18's and i love them. best combination of performance, ride quality and tread life!

 

another reason i went w/ 275 is b/c at the time there was a greater variety of tires available vs 265 (there were cheaper tires available!) the selection may be a bit different now (haven't checked around since i put em on.)

also after doing the tire size calculations i believe the 275/40/18 diameter is closer to the stock diameter. probably doesn't make enough of a difference to throw off vdc but i figured i'd try to stay as close as possible.

 

rear with 275/40/18 ROCKS
275/40/18 mounted on stock 18x8.5 rear rim only exceeds 1/2" in rim width at each side.

 

So if i'm reading correctly. 275/40/18's are safe and dooable on stock 8.5" 18" rims?

 

Not if you follow manufacturer's recommendations they're not

IMHO, 245/40/18 in front and 255/45/18 in back would be optimal. You could push and maybe get away with a 265/40/18 on an 8.5" wheel, but anything bigger is really pushing it. The section width of a 275 tire is 10.9".

Lou

 

I agree with this guy.

 

of course it's ultimately your decision, however there are many people (including myself) that have been running 275/40/18s on stock 8.5s with no problem for years. just sharing our experiences.

fwiw, now that my bfg kd 275/40/18s are broken in and nice and sticky, the z launches pretty damn hard at the track now. used to peel a lot when launching as low as 2700ish rpm--now i can rev it to 4grand and the 275s HOOK.

 

I have 275/40/17s mounted on 17x8 stock rims that I use for autocross. There are many members here who have the same setup without any problems. Here are pictures of my track setup on my tire trailer. First picture has both of my track setup (18" track rims on left / 17" stock rims on right). Second picture is my 17" rims with 275/40/17 tires. Both setups have competition race tires (Toyo RA-1s on 18s & Hankook Z211 on 17s).

 

Aren't those 17's only 7" wide? Thats kinda scary.

 

no, 17x7.5F 17x8R

 

+2
I agree with these guys. Lou's suggested setup is perfect and optimum for these wheels sizes. I cannot imagine any good reason to disregard the manufacturer's recommendation.
--Spike

 

I have 245/35 front and 275/35 rear. With the 03 Track model wheel, it has the same difference in numbers: 30 diff and profiles are same as each other. I have Toyo T1-Rs and it feels like a different car. It just sticks.

 

Im deciding whether to do 255/40/18 or 255/45/18 in the rear and what size to put in front, 45 seems a little bit more in price, why is that ? prob gonna go with t1r's based on their great reviews.