Nuke

I'm replacing mystock 8.5" widefanblades and 235/50/18 tires with GT500 9.5" wheels and new rubber. I've been considering 255/40/18's up front and 275/40/18's on the rear because I really like the staggered look. For the consideration of putting 275/40's all the way around (mainly to allow tire rotation), I'm curious if anyone noticed any negative changes in handling characteristicswith 275's or 285's up front.

F1Fan

Hi Nuke,

The only handling issues you will have with 275/40x18's all around is that the tires will stick a lot better. Your car will also be 1/2" shorter and your wheels wells will look even more empty than before.

HTH!

GidyupGo

It may add more stress on the rear bearings as well. I thought our stock rims were 8.5 inches?

Nuke

You're correct, the stock 18" fan blades are 8.5". I stand corrected.

F1Fan

Hi Nuke,

I just reread your post and want to add that if you use the same larger sized tires all around your handling balance will remain the same as stock andgrip levels will be higher all around. If you go with a staggered wider tire in back than the front think about what you are doing to your handling balance by giving up front end grip. This setup will tend to have more understeer than even the stock balance gives you. If all you do is drive in a straight line and never push in the corners it won't really matter until you get into an emergency situation and the car is pushing like a pig. Staggered wheels and tires can work fine if you take the timeto balance yourhandling using springs and/or anti-roll bars. Then a staggered tire combo can work to your advantage when applying power out ofa corner.

HTH!

Nuke

Sounds like I should go with the 275's all the way around. TY, F1Fan. BIG help.

UrS4

[sm=closed.gif] You could try 285/40/18 all around, it shouldn't rub up front if the GT500 wheel offset is 45mm.

F1Fan

Hi Nuke,

I don't know theoffset ofthe wheels you are going to use but the 18x10 forged Roush wheels with 275/40x18 tires barely clear the strut body on my car by less than 1/4".When I measured the backspacing I get a 44mm backspace onthe Roush10" wheels. This is as close as you can get and still fit. These wheels barely clear the front wheel arches in compression with-0.9 degress negative camber dialed into the struts.The Roush guys really cut this one close. So depending on which GT500 wheels you get and the whatthe offset isyou may be cutting it pretty close going with a 285/40x18 tire depending on the tire make and model though there are only a couple of good perfromance tires in this size. But UrS4 is right the 285/40x18 if they will clear the strutsis a better option if you can get them to fit and in a compound that is appropriate for your use. The 285/40x18 are the same height tire as the stock tires and they fill the wheelwells up much better.

HTH!

Nuke

The SVT Cobra wheel has a 47mm offset (as listed on tirerack) as opposed to the stok rims with 50mm offset. I'm planning on using the Goodyear Eagle F1 all-season and the largest 18" tire they make in an 18" is 275/40. The Goodyear is a little shorter and wider than the stock 235/50 BFG's but I don't believe I'll have a clearance issue.

2007GT/CS

Did you get your MT1s and 285's yet?