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Also been running 245/325 19" combo on 8.5"/12" BBS wheels for a couple seasons now. Not a single issue with fitment, clearance or front diff. Changed the front differential oil earlier this season (original 10 year old fill) and the oil came out golden and clear - almost like new.
Be sure that the offset on the wheels are low enough that the wheel and tire are pushed out to be flush with with fender - see my avatar. This will ensure you have lots of clearance on the inside.
And FYI considering it's related to this topic - technically the 245/325 combo is not the same front/rear rolling diameter as the stock 235/305 setup. It's close, and the general consensus is that it's within whatever tolerance Porsche may or may not have allowed from the factory to account for winter tires, worn tires, etc... The technical match to the OEM F/R ratio is 255/325 but 255 doesn't fit nicely under the front of a 997.1TT. However, those of you with a 997.2TT, they fit just fine as the fender liner is slightly different in the .2 allowing for some extra space.
Someone should be the guinea pig and buy new or used front .2 liners and see if they fit in the .1 wheel well. Then .1's could run the proper 255 front tire. I don't recall anyone trying this out yet.
Cheers
I agree with @cstyles and I’d like to know if anyone has successfully run a
FRONT: 255/35/19
REAR: 325/30/19
combination tire. My new 19x9 & 19x12 wheels are arriving and I’d like to try get the tire sizes right the first time. I like the idea of the 255/325 combo being as close to the factory tire specs as possible to protect the front diff.
The sidewall height between the front and rear are also a nice balance with this combo, as I prefer the meaty tire look and the factory 235/305 just looks too low profile for me.
I dunno… I feel like the sidewall could be fatter. And utilizing a 9” and 12” wheel on stock tire sizes would also stretch them out a bit further giving it the “stretched tire” look.
Have to agree that the taller sidewall looks much better. I have oem tire sizes on custom offset wheels, and if doing it again would go with a 9” and 12” wheel. Looks much more aggressive.
Running almost the exact same setup as @arscottp -- looks and works great. I also ran those tire sizes on BBS CH-Rs at 8.5" F and 11" R with Tractive Suspension + Spacers. Was not as clean (tires were a bit bulbous), but it did work fine until my new wheels were forged.
Actual sizes of tires that are the same size will vary by manufacturer and model of tire. To determine the actual sizes of a tire, I suggest utilizing a site like www.tiresize.com to see what the actual measurements of the specific brand and model tires you are interested in are.
If you are the type that is concerned about how the tires will look on the wheels (for example, same amount of stretch front and rear) or are very concerned about keeping the rolling diameter differences as close to stock as possible, this site is really helpful.
11-02-2021, 05:16 PM
Tire Upsize
