Shelty

i have an 05 GT with stock 17s. will 19s affect the handling? better or worse, or should I just run with 18 inch rims?

Whiskey11

Larger wheels will add weight (unless you spend some good money) which will have some impact on handling by making your suspension work harder at doing its job. Changing the overall height of the tire will have an impact on your final effictive gearing making the car accelerate quicker or slower depending on if you go larger or smaller than stock. If your idea of performance is street only, I wouldn't worry much about the weight issue. The ride may get firmer due to less sidewall but for daily driving I doubt you would be near the limit to notice the change in corner handling.

eolson

If Ford would get it's act together as Chevy has for the Corvette line, their would be 19"x10 rear/18"x 9 front wheel combos available for the mustang, and Ford would have a great summer tire combo made by order to fit the Mustang to it's maximum size tolerances.

This would be 305/35/19 rear (for a 27.41" tire height) and 265/45/18 front(for a 27.39" tire height). This height diameter is perfect for filling the large Mustang wheel wells optically, and is very close to stock which is 27.2 for the 235/50/18 stock height.

It is amazing to me that the most popular Muscle car ever still does not have this combo available for the Mustang. Get it together Ford!!!! Erik

Norm Peterson

The Mustang is an entirely different sort of car, so it is not reasonable to expect that what works on the 'Vette will directly translate over to the Mustang.

Putting the appearance issue aside for a moment, a 19x10/18x9 combination with proper tire size choices is going to understeer a little more than when all four tires and wheels are the same.

The current Mustang has been getting consistently high handling ratings relative to its more direct cometitors (Camaro, Challenger) in spite of still having a solid rear axle vs the IRS arrangements in the other two. In daily driving, that tends to mean a slightly more nimble feel, that the car drives "lighter" than it is. I'd say Ford has been doing this part of the car's design consistently well.

For the appearance factor, having an OPTION with staggered wheel sizes might be worth Ford's consideration, assuming that they can get it to satisfy whatever other standards that might be affected by such a choice. They did get the GT500 to have tire size stagger, though I understand they were trying to avoid it.


Shelty - I have the 18x9.5 GT500 wheels and 255/45-18's all around, and have no complaints about the handling up to and including something like this . . . and in street driving you shouldn't be driving hard enough to get the inside front tire quite this close to being unloaded (and if you look closely at the right rear, there isn't a whole lot of weight on it compared to the left side tires either).




Norm

eolson

Thanks Norm. I've always been frustrated with the thinner tires that were available for the 05 platform, and the way that 275/40/18 always look puny inside the wheel wells, or most any other tire to try to get wider with more grip not being available wider that 285 with out going to a R-compound. To me it's been the lack of launch grip because of the narrower tires being super charged and the puny looking tire selection when wanting wider tires. Erik

Whiskey11

Cost is probably the largest reason why they won't do this. Big tires are eensive. Heck, 245/45/18 direzza star specs are 214$ each and that isn't much different in size compared to the bfg kdws and pirellis which are in the 140$ range. It also prevents tire rotation on all corners of the car.

Norm Peterson

In your case, I think you'd gain more from a softer tread compound in a 275/285 wide tire than you would from 20 or 30 mm more width at the higher treadwear numbers that most street rubber comes in. NT05 vs NT555, for example.

FWIW visually, mounting any given size tire on wider rims actually does make the tire wider across the sidewalls. For example, on 9.5" wide wheels there isn't nearly as much visible difference between 255/45's and 275/40's as the numbers might suggest (because the 275/40 is measured on a 9.5" wide wheel to begin with, and gains nothing, while the 255/45 gains over 3/4" on a 9.5).




Norm

eolson

Thanks Norm. I am due for new summer tires next spring as my Nitto 555's were bought in late may of 06', and have lasted well for six seasons of use, and nearly 34,000 miles of spirited driving(not a lot of standing burn outs though).

Norm or anyone have any suggestions from actual experience or great write ups for a lower than 300 wear rating(nitto555s are 300) on various summer tires in 255/45/18 front and 285/40/18 rear????? I know Pilot Sports are lighter than some, how's the grip??

Thanks, Erik

jdmcbride

The 2011 GT500 with the performance pack staggers 19" fronts with 20" rears. Ford uses 265/40/19 and 285/35/20 tires. I saw one at the ford dealer a week ago and noticed that the car looked more balanced (visually).

Norm Peterson

Most times since treadwear numbers were introduced, I've stayed at or below about 220 treadwear for my replacement tires. I seem to get about 12,000 to 13,500 miles per hundred treadwear, so I'm not complaining.

Unless I have solid evidence to the contrary, I look at the higher treadwear numbers as having traded off at least a little grip and good general cornering manners in order to get the extra tread life. I know that for me, that's a bad trade.

It's been "so far, so good" with the Goodyear Asymmetrics on the '08 (they're on the car in that autocross picture, essentially at full tread depth, and I'd have placed in the top quarter of the field if I'd been an official entrant). Very good street manners as long as the thermometer registers high 40°'s F or higher, though like all summer performance tires they aren't nearly as grippy at temperatures much below that. That's when the OE 235/50-18 BFGs go back on.

FWIW, I'm making power comparable to a 2008 Bullitt, but with 3.55's in the axle instead of the Bullitt's 3.73's.


Norm