So I have the factory 18 inch turbo wheels on my 996tt and have a line on a set of 997 turbo factory wheels (fronts 19x8.5 with 57mm offset and 235-35ZR19 rears 19x11 51mm offset and 305-30ZR19) Can someone tell me if I can install these with absolutely no risk to my AWD, no rolling fenders, etc. I want to bolt on and never think about it again.

 

The rear tires are too tall. They will toast your front differential. The proper size is 315x25x19 which only Nitto makes anymore. I didn't check the offset but you should plan to roll your rear fender lips. The PSM and ABS are calibrated for the 18" wheels and tires. You can turn the PSM off but the ABS will still act up. Wider wheels and tires add unsprung weight (detrimental to handling) and and rotational mass (detrimental to braking) 19" wheels are for show and 18" for go. The stock hollow spoke 996T wheels are well made and very light for cast wheels. Unless you're willing to spend the money on some monoblock super light forged wheels, I'd stick with what you have.

 

Thanks for the words of wisdom. I'm confident the engineers at Porsche did their homework and I definetly don't want to mess with the goodness they baked in just been looking for a little more edginess from the factory wheels thanks again for your sound thinking

 

Just went through this, I ended up ordering 315/25/19's for the rears from tirerack and kept the 235/35/19's up front. they fit great. With the stock tires "305/30/19's" on factory suspension you will rub. not to mention they mess up the viscous diff.

 

Using a tire comparison app online it was showing 225/35R19 and 315/25R19 being dead nuts on diameter, sidewall height and of course revs/mile but I was wondering is there an optimum "mismatch" to keep the AWD happy? With the 315/25 no fender rolling or risk of rubbing? What offsets were used?

 

factory 997 turbo wheels so whatever offset those are. no rubbing, but my car is on stock suspension. I did however order 14mm spacers with bolts just to make the back poke out a little more.

 

Here they are bolted up.

 

18" BBS E88's

 

Very nice! E88 is a true race wheel and the only modular wheel I would ever run. They are super light. Too bad BBS is just too much of a pain in the **** to deal with if you need replacements in a hurry and they still don't offer bead knurling which makes them less than ideal in high hp applications using slicks.

 

I still have my 18s but drive around on the streets on 19s. They may not be as efficient as 18s but it makes me happier with the car during regular driving.

 

19" HRE 843

19" HRE 540

 

urg, I want those ducts oak! lol

 

I've never seen an E88, or any BBS wheel with bead knurling. Every one I've had my hands on has had normal barrels with smooth beads as can be see below. Post up some pics o E88 knurling please..


[url=https://flic.kr/p/JqD1Gu]

[url=https://flic.kr/p/HDutYU]

[url=https://flic.kr/p/JqD1gu]





By the way, this is what I'm referring to by the way when I mention bead knurling..

[url=https://flic.kr/p/J9W1Cw]