How we selected tires and wheels for the track

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Update by Tim Suddard to the Porsche 911 Carrera project car
Dec 5, 2022 | Porsche, 997, 911, Porsche 911

Are Porsche Lobster Claw wheels timeless beauties or ugly abominations that should be banished to the back of the garage?

Doesn’t matter how they look: They’re heavy and a bit too narrow up front.

Even though our Porsche 997 wore fresh Bridgestone Potenza Sport tires on those Lobster Claws, we knew we could do better.

Our ideal wheel-and-tire setup: one that makes this …

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Comments
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kaybat
kaybat New Reader
12/6/22 1:25 p.m.

That fitment guide they have is handy(especially for someone that has no clue how to size tires) :-) It's a great starting point.

docwyte
docwyte PowerDork
12/6/22 2:49 p.m.

Not sure why you didn't go with the widest wheel possible for track use?  I'm personally using the Apex wheels in 9" front, 12" rear on my 996tt, very happy with them and they fit perfectly without rubbing.

Tim Suddard
Tim Suddard Publisher
12/6/22 4:41 p.m.

In reply to docwyte :

Trying real hard to keep this car truly streetable. The goal is to drive 500 miles comfortably to an event, do that event and then drive home. If I did drive, I would have to live with the track tires and wheels on the road. Took a 200 miles trip last week and they were fine for street use.

Tim Suddard
Tim Suddard Publisher
12/6/22 4:41 p.m.

In reply to kaybat :

I thought it was pretty handy too.

CAinCA
CAinCA GRM+ Memberand HalfDork
12/6/22 5:22 p.m.

I'm running the 9x18" and 10x18" SM-10 on my Cayman with 245/40/18 F and 275/40/18 R tires.  One word of caution. The Apex wheels have less offset than the stock wheels. After I added the GT3 arms and 16mm of shims my wheels wound up with a bit of poke. Thankfully they don't rub.

docwyte
docwyte PowerDork
12/7/22 10:02 a.m.

In reply to Tim Suddard :

Ok, but I still don't see how the wider wheels impact that?  Like I mentioned, they fit my car perfectly fine, with no rubbing at all.

350z247
350z247 Reader
12/9/22 10:19 a.m.

In reply to docwyte :

If they went with the 12 inch rear, they would just maintain the rear-biased grip they were trying to correct, and the 9 inch fronts require 2 degrees of negative camber to not rub which is going to eat tires. Their pick seems like a good compromise between practical and performance.

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
12/9/22 3:22 p.m.
docwyte said:

In reply to Tim Suddard :

Ok, but I still don't see how the wider wheels impact that?  Like I mentioned, they fit my car perfectly fine, with no rubbing at all.

Wider wheels means more tramlining, which could be a pain on the street, and possibly a slimmer selection of street-friendly tires.

(Wouldn't stop me though, I like wide tires and I cannot lie laugh)

docwyte
docwyte PowerDork
12/9/22 3:31 p.m.

I run the same width tires on 8, 8.5 and 9" wheels, same with the 11's and 12's.  Will a 245 tramline more on a 9" wheel vs a 8.5"?  Kinda doubt it.  Will a 9" wheel need 2 degrees of negative camber to fit?  Maybe, I run way more than that and can't say I see any aggressive tire wear on my car.  That being said, it's not a daily driver, so isn't seeing 10-15k miles a year.  My front tires do have close to 10k total miles on them tho and they're not all chewed up by camber wear. 

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