My 07 GT came stock with 235/55R17 tires on the stock 17" wheels. I'm not sure on the width of the wheels, but I thought they were 17x8's. Can I go to 245s or 255s on the front and the rear? Or should I stick with the standard 235 size? I plan to run a set of good all-seasons for year-round use in Michigan (snow, ice, rain, dry).

I have factory Goodyear Eagle RS-A in 255/40R19 on my 2014 SHO and they are surprisingly good in snow and ice, which shocked me since RS-As are one of the worst tires, and the 255s are much wider than what I'd expected on a sedan.

 

Why do you say the Eagle RS-As are a bad tire? This is a Police tire that works extremely well in the snow and rain. I had Pirelli PZero's, hated them. No grip at all in the rain. Had the BFGs that came on the Bullitt wheels, and they were a very nice tire for the Mustangs. Good bite.

I recently changed to Eagles and I could drive in the snow with no problems. Much better than the Goodrich's even. Why would Chev, Ford and Dodge offer them on their police units? Each company has a favorite, but the Eagles seem to have the most requests. Continental makes a great Police tire also in this very size that Dodge lists as an option for the v6 PPV version. The Impala is almost entirely Eagles now. Ford goes to the purchasers specific tire request but the Eagles are the primary ones delivered. Just another reason, in the line of so many good innovations, that's why Ford has taken over the PPV segment. Those new Taurus PPV's flat out scream.

 

The RS-As traditionally are terrible tires once they start to wear down a little. Brand new, they are good. They've been using them as police tires for over 15 years and they were mainly used due to being inexpensive for fleet buyers ($75 or so for police departments).

The BFGs on the Mustang were also used on the Marauder and wore out very quickly. My stock Pirellis still look brand new but I've heard about horrible snow traction. I know the RS-As are wearing down very quickly on my SHO.

 

Can I safely run 255's on the stock 17x8 wheels? or maybe just 245s?

 

I'm running a 255 tires on my 8 inch wide 18 inch wheels. Just too much tire roll for my taste on a hard turn . I'm going back to the factory 235 width when these tires wear out

A 245 might be better than a 255 but all the 245 tires in the 18 inch wheel were a little too tall.

 

I had a set of BFG Sport Comp 2's in 255/45R17 installed. They are significantly better than the 11 year old factory Pirelli's