tires. Would changing to a 275/40/19 in the rear work with these rims? I think they are 8.5"..Would changing to this bigger tire help the car grip better from the line if i added more power?

 

I have seen people put 285s without any problems. I have the same wheel/tires

 

I agree with what Adrain said. I would say yes to your traction question But it depends on which tire/make/model you go with as well as what the contact patch is. Some tires have a narrower contact patch than the actual width. Hope that made sense.

 

275's on a 8-1/2" wide rim is not going to perform well. It may mount, but not a good marriage.

 

I have the same 19" x 8.5" wheels as elvism. I really like the wheels, but I would like to improve on the 245/45 19 tire size. Any safe suggestions?

 

http://lmgtfy.com/?q=Maximum+tire+wi...5inch+rim#seen

 

I found this chart on-line, it may be helpful...
http://www.tiresandco.ca/equivalency-tables-advice.html

 

That chart is retarted. I have a 9.5in rim in the back and run a 285 without any problems, and it hooks like hell.

 

I agree
A 255/40 like the Brembo cars have would be best.

 

The only reason i picked the 275/40/19 is because this is the only size up in the same tire brand as the stock front tires. will the car feel any different?

 

Chart is messed up. They jump 10mm from line to line on the change in rim size while the rims are getting 12.7mm per jump wider. Obviously there's no way this can be consistent.

My advise is to look at the manufacturers website for their rim recommendations. Just off the top of my head, I'd say 265 is the widest you can go on an 8.5" rim without bulge, 255 is probably a better fit.

 

Thanks for all the good info. I do like the idea of using the Brembo size, 255/40 19. I just wish someone has already done this, has pics, and can advise how it looks and drives.

 

The V6 Performance Package wheels are the same size as your wheels (19x8.5), but use the same tires as the Brembo Package wheels (19x9). You'll be fine.

 

Thanks, laserred38, you are correct, I see the V6 Perf Pckg uses 255/40 19. But are you certain that wheel is 19x8.5?

 

Yep it's the same wheel as the GT/CS, but no GT logo and black windows instead of Sterling Gray...

 

Great, thanks! Then I'll go with 255/40 19, with a summer performance tire. I find it really strange that Ford would equip GTs (like mine) with a smaller all-season tire, annoying.

 

Yeah it's definitely not enough tire for 400+ hp. I'd recommend the Hankook V12, General Exclaim UHP or Continental DW/DWS. I've used the Generals and many guys on here have used the other two, with great results for a daily driver.

 

Lesser width all-season tires are a little better in the snow They also cost less to replace.

 

I'm sure the narrower all seasons also offer lower rolling resistance which helps Ford in the mpg ratings...

 

Thanks! I live in Las Vegas, so snow/rain is no issue. I've had the Hankook Evo V12 on my Infiniti G35 and Audi A4, and they are great in the dry, and acceptable in the wet, so I will put them on my new GT in the better 255/40 size - as soon as I burn up these OEM all-seasons.