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325/30/19 Rear fit?


2012 500A #1626
Wondering if anyone knows if a 325/30R19 (Michelin PSS) will fit in the rear, even if locating the rear (PHB or Watts) is needed.

Instead of having to pick something that fits the rim, or something in a popular size for track tires, I wanted to see what tire offered improvements where I want it but still fit the overall diameter as the factory 285/35/19. Thanks to DiscountTires' calculator, I found the Michelin PSS 325/30/19 to be wider but very close elsewhere:

Section Width: + 1.58" (wider)
Sidewall: - .09" (shorter)
Overall Diam.: - .17" (smaller)
Circumf.: - .36" (smaller)
Revs/Mile: - 3.18
Speedometer reads 65MHP, Actual Speed Will Be 64.57MPH

This is for aggressive street use on a a daily driver; I'd like to make the most of the Boss's power in 2nd & 3rd gear. I'm careful when it's wet or cold, as required by the factory Pirellis, and use the wife's vehicle in the worst of it. I'm in West Texas, so it gets plenty cold but I can make do with summer-only tires without too much concern (but with due care). Replaced yearly.

So 19" because it fits the car for the street, IMO. I'll go wider in the front to help retain the balance of the car, as I have no complaints on the street. That said, I'm looking to gain traction and not degrade the aggressive street driving experience.

If it fits, I'll pick/order my rim according to what the manufacturer suggests for the tire. I know this leaves me with few choices (Nitto Invo is half the price) but the PSS in 325/30/19 looks like what I'd want if it did fit, so I don't mind buying them if I can make them work. I've been buying the factory Pirellis as it is. ::)

Any help or suggestions appreciated! Would rather gain traction with more rubber than look at putting the 3.55 rear in the Boss.
I have seen a few pictures of a 325 30 19 on the back of a Boss 302 using a 19 x 11 rim and it fit but looked quite bulged on the rim. As far as I know, Vorshlag is the only one that has put a 12" wide wheel on the back of a stock bodied mustang for handling purposes. They use a watts link for lateral control to get that done with minimal rubbing. My set-up is a 19 x 10 with a 295 30 19 MPSS front, 19 x 11 with a 305 30 19 MPSS rear, and that all fits without any rubbing. The car is lowered about 5/8" front and 1-5/8" rear and utilizes a watts link.
With a 315 Hoosier on an 18x12 in the rear we had slight rubbing on both inside and outside the inner fender during extreme bump. If you limit the bump travel you may be able to get a 325 to fit without rubbing, but I don't think we could get it done on a roadcourse.

There are some flaring tricks you can to by separating the inner fenderwell from the outer body skin that will increase tire room without making an obvious flare like we did to run 345s. It wasn't enough to run a 345 on a roadcourse, but it should be plenty for drag use or a 325 tire.

345 under the stock fender

345 under the fender with a modified inner fenderwell
gremlinsteve said:
wow, that 345 looks tight. neat how you got it on there though.
any other pics of that setup?

Well, since it didn't fit, we punted and did real flares. They are covered pretty well in the Vorshlag blog.




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