Tire size help!!

[Johnson505]

I have a '03 GT with stock Bullitt rims. What is the biggest tire I can use with this set up. I am planning on running the same size all the way around and I am thinking about pro kit springs in the future. My Goodyears don't even have 17,000 miles on them and they are about shot. I guess I have been enjoying my 4:10's too much.

Thanks,

 

[Kurgan]

275/40R17, I believe. But I would only go with that size for the rear.

If you want to run the same size all around and be able to rotate your tires, I'd stick with 245/45R17. I think you might be able to get away with a 255/45R17 all the way around, but that might mess with your speedo just a little bit. 275/40R17 is the same diameter/perimeter as 245/45R17.

A lot of people who buy drag radials for the rear will get 275/40R17.

 

[RoadconeTuning]

if you goto 275/40r17 go ahead and buy 17x9" wheels, they will fit a LOT better and look better too.

you CAN put a 275 of all 4 wheels but you run the risk of pulling the bead off the wheel in a heavy load condition if your turning.

 

[Dope 97GT]

if you goto 275/40r17 go ahead and buy 17x9" wheels, they will fit a LOT better and look better too.

you CAN put a 275 of all 4 wheels but you run the risk of pulling the bead off the wheel in a heavy load condition if your turning.

yeah prolly just go with the stock size of 245/40/17s cause i believe they are onlly 17x8s stock. the 275s may be to wide. or go buy 2 17x10 DD bullitts for aout back and put some 295's on em.

 

[merc123]

Shouldn't run 275's on a 17x8 wheel. I would say stick with 245 or go with 255. I would suggest getting aftermarket, larger wheels to go wider.

 

[goshia]

I have been running 285's on the back stock wheels all summer, no problems. I will be removing them for the winter next week as the track season is coming to and end for the year...

 

[bullitt_2620]

I've got 255-40s and I think my speedo may be off my most of 1-2mph, checked on those radar things that show your speed. But I really did notice a difference between the feel of the 255 vs the 245, I say get the 255 if not 265.

 

[merc123]

I have been running 285's on the back stock wheels all summer, no problems. I will be removing them for the winter next week as the track season is coming to and end for the year...

285's on a 17x8 rim? The minimum recommended width is 9.5. I run 275's on my and I have 17x9 wheels. 285 is just plain nuts on an 8" wide wheel...

 

[Dope 97GT]

285's on a 17x8 rim? The minimum recommended width is 9.5. I run 275's on my and I have 17x9 wheels. 285 is just plain nuts on an 8" wide wheel...

+1 i dont see that working that well. I had 285s on a 10" rim and they werent too small on that...are you sure they are not 17x9s not 8s cause thats crazy.

edit: i see that you have nittos and they generally run smaller so it may work but that is still a stretch.

 

[Johnson505]

Thanks for the info. I am really looking for some more side wall to fill in the wheel opening. I am not sure if lowering the car is what I want to do yet. I figured 1 or 2 sizes taller would look alot better than the stock size. I am not worried about the speedo since I have a speed cal already from installing the gears. More comments will be great.

 

[CRZYHRSGT]

Last year when I first got my FR500s I put on a set of 255/45R18s (freebees from an Audi at work) and they filled in the wheel arch gap nicely (esp. already lowered). Although, now that I've gone to a 275/35R18 and see what the sidewall is supposed to look like I wish I'd gone with the right profile to begin with. The taller sidewall should give you a softer ride, but also softer around corners (which sucks if you dig into corners like I do). Long story short, if you're thinking about doing springs I'd keep the stock tire size on the stock rims and let the lowering springs fill in the gap for you.

 

[goshia]

It has some buldge but a much better feel on the track, No problems driving daily either...

+1 i dont see that working that well. I had 285s on a 10" rim and they werent too small on that...are you sure they are not 17x9s not 8s cause thats crazy.

edit: i see that you have nittos and they generally run smaller so it may work but that is still a stretch.

 

[jivepepper]

I ran 275/40/17's on all four for a while. It will slow the car down a good bit. More rubber to push down the road.

 

[SeanD1111]

Thanks for the info. I am really looking for some more side wall to fill in the wheel opening. I am not sure if lowering the car is what I want to do yet. I figured 1 or 2 sizes taller would look alot better than the stock size. I am not worried about the speedo since I have a speed cal already from installing the gears. More comments will be great.

If that is what you want to do then go with the 255/45/17, like recommended above. It is 3/8" larger than stock and will not f' with your speedo too bad (i.e. Speedo says 60mph, your actually going 60.8mph).

You have to remember, the sidewall number is just a percentage of the width (first number). Its not actually a "hard" number.

Different mfg's will make the same size tire but each will be slightly different from one to the other (there all within a few mm of each other though). Nitto, for example, tend to run a bit smaller than the norm. Kuhmo, seem to run right on or a bit on the large side. You get the idea.

 

[Kane]

I've got 18X9's all the way around, with 255s in the front and 275s out back. My stock wheels have 234s all the way around. Get a wider wheel if you want to run anything over 255.