My 09 GT came with 17" wheels so I thought about upgradingd to 18", will 18X9 all around be ok or will they hurt the performance....Will I have to retune the car for bigger wheels?????????

 

It will increase the performance to go with wider wheels. 18in wheels dont weigh that much more than the 17in wheels. When you buy new tires you always want to stay near the stock size which is 27.2in diameter. If you went with 255/45/18 you would be right at 27in so you revs per mile would be very close. They will let you know what works best when you buy wheels and tires. I would personally go with the 18x9 wheels in front and 18x10 out back with 255/45/18 in front and 275/40/18 in the back. If you look on www.latemodelrestoration.com they have some good packages for right around 1k for wheels and tires shipped.

 

Changing wheels does not necessarily require a change to your speedo as long you maintain the same aspect ratio as the stockers. As an example, I am running 18x9.5 on all 4 corners, but have staggered tires... 285/40 rear, 255/45 front (which is the same tire/wheel sizes that come stock on GT500s).

But if you do run a different diameter tire, you can reset the speedo via most any handheld tuner.

 

I found these wheels on -tirerack- that weigh just 11 lbs and some 18x9 that weight 16 lbs, stock 17"s weight about 21 lbs and most "Mustang" type 18"s weight about 25 lbs...... Would there be any concersn about having wheels that light as much as 11 lbs????????

 

Could you post the link to those 11 lb wheels? I need to see if they're made from balsa wood. I think the lightest wheels (worth a darn) for the S197 were around 18 lbs.

 

http://www.tirerack.com/wheels/resul...&filterNew=All

I sorted them by weight, the Enkei Performance L-SR 18x8 weight 11.4 lbs

 

I wouldn't recommend running 8" wide wheels for tires wider than 235/50, maybe 245/45 at the very most . . . go with the 9" for up to 275/40. 285/40 really belongs on 10's or slightly wider.

I suspect that Ford really didn't want to have different wheels for front and rear on the GT500, and the 9.5-wide wheels there are max for the 255/45 and min for the 285/40. I doubt that that's just coincidence.


Norm