Jcreek79

I have some 2011 GT premium wheels to throw on my 05 GT. It needs new rubber and i'm trying to decide to go with the 245/45's or go a lil bigger. I'll also be doing SR springs and Koni STR.T's. Was thinking of going with 275/40 square? Any thoughts?

Jcreek79

I've done some research and I know 275's are not recommended but I fear the stock 245/45's would look too tiny and 255/40 would add back much of the wheel gap that lowering it would remove lol. I got the wheels for $150 on craigslist to try n budget my spending for this year. Ideally I'd like to have some AMR wheels or somethin, but this is it for now

Bert

First, you need to know the wheel width. If you have the wheels off the car, look on the back and it should be marked on there.

Also you need to know the overall diameter of your old tires. Usually it is about 27.2" on most of these cars. You can find this by looking up your old tires on Tire Rack and checking the specs to find the diameter.

Next, look up the tires you are considering on Tire Rack. You can go to the "sizes" tab to see all of the sizes available; and look at the recommended wheel width and the overall diameter. Make sure the wheel width that you have is in range; and the overall diameter is pretty close to the original diameter. To reduce the fender gap you can go with tires that are a little larger diameter than original; but keep in mind this will throw off the speedometer by whatever proportion the new tires are bigger than the originals.

My best guess is the wheels are probably 8" wide and 255/45 is about the biggest you can go on those wheels. But that is just a guess, look it up . . .

ElkGroveFordGuy

if they are 8.5 rims 255/40/19 is as big as you can go.

m05fastbackGT

You might be able to get away with 265/40/19's on a 8.5" rim, but as other's have posted 255/40/19's are as large as you can go that are recommended for 8.5 size rims..

Jcreek79

That's what I had assumed, thanks for everyone's help. I would go 255/40 but that's gonna cut down my sidewall height compared to the 245/45. I'll just stick with 245/45.

m05fastbackGT

Then consider upgrading to 255/45/19.. As long as your sticking with 255 size tires, there shouldn't be any fitment issues on 8.5" rims.. You could also look into 245/50/19's if their available

Bert

You can increase the overall diameter a bit with no problems, other than throwing off the speedometer. That 4x4 fender gap provides plenty of room for bigger tires. I think you could actually go up by about 2" on the diameter without any clearance issues.

Small tangent: I have read that all that clearance is there for tire chains! So if there is clearance for big old hairy chains, there is plenty of room for a little bigger tire.