I have a 2012 997.2 Turbo S with the OEM center lock (CL) wheels (19.0x9.0 front wheels and 19.0x12.0 rear wheels with OEM tires). The car has PCCBs. Question: IN AN EMERGENCY-only situation (say stranded in the middle of the Mojave desert) I have a flat in a rear tire with damage to the sidewall, and therefore not able to use the sealant/compressor or a tire plug kit to fix it), can I mount a front 19x9 CL wheel on the REAR of the car? Would there be any question with regards to clearance for the PCCBs if I mounted that front wheel/tire on a rear position? I am considering purchasing an OEM 19x9 CL wheel/tire to take with me as a spare tire. Yes, I know that one could have the car flat-bedded to the nearest repair facility; and, yes, I am familiar with the process of removing and reinstalling a CL wheel having done a rear tire just last week - I have all of the tools and grease necessary already. I am just asking if it is physically possible to mount an OEM CL front wheel/tire on a rear position and be able to drive the car to the nearest repair facility. Is the rolling diameter of the OEM front wheel/tire significantly different from the rears? I understand that these tires are unidirectional (i.e, designed for a specific side of a car) - are there any issues with the fact that I might have a spare on the "wrong side? Is there a problem with the fact that these are CL wheels in terms of any stresses that might be induced due to mounting a front OEM wheel/tire to the rear position (assuming that I am limping into the nearest repair facility, say not exceeding 55 mph)?

 

Wrong forum?

 

https://rennlist.com/forums/racing-a...completed.html

 

LOL. I was at lunch with a buddy today and that is exactly what he suggested - get a roof rack and put the spares up there. I guess I could tell everyone I was on my way to the track with my racing wheels...

 

I doubt anyone has done this...so it looks like you'll have to jack up the car in the garage and see if the front wheel will work on the rear. The tires are asymmetrical not unidirectional so as long as the sidewall says "this side out" you can move side to side...but again the issue will be the large size differences and whether there is enough clearance for the PCCBs. We'll wait for your report. Good luck.

 

Won't work, it will fry the front differential.

 

Chris: thanx - just the kind of info I needed. So the only other option would be to have both front and rear OEM wheel/tire spares and then I would need a roof rack of some sort to carry them. Maybe I should just ship the car to Cali - might be simpler...

 

Hmm...that is a question and half!!!!

Front and rear hub center are the same. so that is OK.

Why don't you jack up one side of the car and put the front on the back and see if it clears and the backspace is OK? Front calipers are bigger than the rear, so the hub should clear the brakes.

--> My estimate is that it will work OK, but if NOT, then you can also carry a spacer and 5 longer bolts with you. My estimate is 15mm but I don't have wheel offsets memorized.

--> Assuming you are running stock tires (235/35X19 and 305/30X19)...You can have front to rear diameter bias of less than 3%, but side to side must be zero. However, in case of an emergency...If this was me, I would drop the air pressure on the rear (stock side by 6-10psi) and the spare would be at full maximum pressure (45?). That would get the side to side bias safe enough to get to a place and repair the car. This is for emergency only.

 

You will burn your front diff, but if you are lucky you will get a PTM error that it is overheating. So in cases of emergency you could drive a short distance, wait for the diff to cool down, then drive again. I had an issue with tire sizes front/rear and basically with as little as 1/2 inch of circumference difference the PTM went wacko (not 1/2 inch diameter, but 1/2 inch of circumference).

It manifested itself when I would come off the gas and the front would start veering quite hard one way then the other, as the diff would transfer power from one side to the other as it kept thinking that the car is going out of control. To cut a long story short, the PTM overheating error would come on as quickly as 3-4 miles of normal driving.