Guys,
Can anyone verify or refute my concern that going to these tires with a stock suspension ride height will result in an exacerbation of the already unsightly stance of the BBP Mustang GT?

 

I just replaced my stock 245/45-19's with 9.5" wide TSW's & 275/40-19 square setup last week. One reason I went this way is I may never lower, and either setup gives you about 27.66 OD and fills the wheel well pretty good. Some may not like the taller sidewall versus what they run, but for my DD it provides a great ride and fills the wheel well nicely. Off the top of my head I want to say it's over 1/2" taller than a factory Brembo setup. I was also advised to stick with a taller tire with my 3.73 gears.


Go to a tire calculator and plug in your factory size and then compare to whatever you are interested in and see exactly what you will be getting.

 

Good info... thanks.

So
255/40/19 = 27.031

275/35/19 = 26.579
275/40/19 = 27.661

It seems like a toss-up for us stock 255 folks... 275/35s are .5" shorter, 275/40s are .6" taller

As someone with a 3.55 axle I'm inclined to lean towards the 35s but THAT likely would look bad on a stock suspension. Hmmm.....

285/35/19 = 26.854
285/40/19 = 27.976

^ probably too wide for stock BBP wheels... correct?

 

The 275/40's are only going to give you a .3" taller sidewall so you would hardly notice the difference in height.

 

According to the numbers that I found, it's +.63" which is probably noticable.

 

Ok... so there is a lot of debate out there about putting 285s on 9" wide wheels but many folks are opting for them without any problems.

This opens up some possibilities...

 

But the sidewall height only increases by .3", half top, half bottom, get it?

And 275's are pushing it on a 9" wheel, at least from an optimum performance standpoint, 285's are a no go IMO.

 

Here is what mine look like. 275/40 19 Pilot Sports on stock track pack suspension.

 

When you're calculating the % change in the impact on your final drive ratio, the over all diameter is what you would use.

I think you might be right about the 285s not being optimum for performance but quite a few folks have done it and they're happy with the results... not scientific, of course but nobody is seemingly having abnormal wear or a tire slipping off the bead. How much of a roll the extra deflection makes in performance is hard to tell from internet forum posts.

http://www.svtperformance.com/forums...-too-wide.html

Those look good...you car rides about as high as mine does with the 255/40s... so that might not be an issue. Thanks for posting up the pics.

 

I wouldn't go more than 275 on a 9" wheel. The 9 1/2 is perfect for a 275 IMO.

 

I was only commenting on whether you would notice the increased height very much, which you wouldn't with such a small change in sidewall height.

And the impact on the final drive ratio wouldn't be a big deal either.

 

Honestly I don't really notice.

 

275/40/19 Cooper RS3 A's on stock Brembo suspension





BTW some manufacturers have been putting 275 width tires on 9" wide rims from the factory since the mid 90's so it isn't an issue.