Hello all,
I'm new to the forum so please don't roast me too hard if this is in the wrong spot or has been asked 38 times, I tried finding what I needed and couldn't find exactly what I was looking for. I got a 997.1 less than a week ago, my first 911 fulfilling a dream 18 years in the making.
I love the car, but admittedly the wheels are probably my least favorite factory wheel (just my personal taste) so I was looking to put on a set of aftermarket wheels. My 997 is a base narrow body, however the previous owner had put the S wheels on it. They are an 11.5" wide wheel with a 67mm offset, according to this thread the standard wheels would have been 11" with a 67mm offset. My calculations show this means these wheels stick out 6mm further than factory. Additionally there are 12mm spacers on the back bringing the total to 18mm out from factory. The car was also lowered and the camber is not within factory spec (the inner tire is super bald while the outer is fine), to keep the tires from rubbing the quarter panel. I've noticed that many after market wheels are an 19x11 with a 52mm offset which puts it 15mm out from stock.
So my first question is, will a 19 x 11 with a 52mm offset really allow me to a factory camber setup? I really don't want to burn through tires because of bad camber, rear tires are way too expensive for that.
My second question is around the tires themselves. Everything I read on here seems to indicate that a 295 is the proper tire for an 11" wheel and a 305 would be correct for a 11.5" wheel. My current setup is a P Zero 295 on an 11.5 in wheel, but yet the sidewall of the tire sticks out 8mm passed the wheel lip. Can anyone explain what's happening here? I would expect a 295 on an 11.5" would be a slightly stretched sidewall and thus not be sticking out 8mm passed the wheel lip. Do different manufacturers have inconsistent sizes?

 

Looking for some help here. I have a 2009 cayman which has been run in gtb1. The formula 43 wheels just developed hairline fractures. front is 9' wide with 7mm spacers. Rear is ll" wide with 7mm spacers. What is the offset. I am trying to find new wheels and am out of my depth.

 

Regarding the tire wear that could either be from a couple of things. First, the increased negative camber from a more aggressive alignment from the previous owner (PO) or a result of PO lowering the car which will add some negative camber by changing the static angle of the lower control and pushing the bottom of the wheel/tire out. Another culprit could be the Toe is out of adjustment killing the inner shoulders of the tire, can't know for sure without going to an alignment shop. Finally this could just be a case of the rear suspension on 911s killing rear tires. From my time at a Porsche independent shop it wasn't uncommon to see rear tires wear drastically quicker than the fronts, below is a link to another Rennlist post discussing rear tire wear.
https://rennlist.com/forums/991/1205...he-rear-2.html

We normally recommend Front: 19x9” ET50 and Rear: 19x11” ET60 as our OEM+ fitment which is just 7mm more aggressive in the rear than stock. Normally wrapped in Front: 245/35-19 and Rear: 305/30-19 but with the option to go with OE C2S 235/295 or GT3 235/305. This is a direct fit solution for people who do not want to worry about alignment fine tuning and just want to bolt on the wheels and tires and drive.

You are correct about different tire manufacturers and even models measuring out differently. We normally see this on high performance 200TW and below, which are generally developed for track days or competition use. But in this case lets look at the specs of your P-Zero in 295/30-19. While the tread width of the tire is 11.5" the section width is 11.9". All this to say the tire can be stretched on the 11.5" (which it is) and still poke at the base where it meets the wheel. Different manufacturers also design the sidewall of their tire differently with different amounts of poke beyond the wheel surface. If you have any questions regarding your particular vehicle feel free to shoot us a PM, I will be happy to help.

- Brandon

 

Some manufacturers have a lip or rim at the wheel to prevent (reduce) curb rash. That's what you are seeing. To add to the complexity... sometimes different sizes within the same family do or do not have that rim.