Tire sidewall to fender lip relationship question 997.1 Turbo
11-01-2017, 11:32 PM
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Tire sidewall to fender lip relationship question 997.1 Turbo
Several months ago I acquired a mint condition 07, 997 TT with 15K miles and a beautiful set of 20" RG5 Champion wheels 8.5 Front and 11" rear -and life was good.
However- the wheels were obviously for the NB and not the WB so I got a set of 18mm spacers for the rear to correct the offset and 3mm in the front which looked great and life was even better.
Then I started reading where some guys have had front differential problems due to the tires not being matched properly for the AWD system. So the guy who owned the car before me had put on a set of Michelin PSS tires sized 245/30R20's up front and 295/30R20's in the rear. The overall difference in diameter with this setup is 4.6% larger in the rear and the OE recommended tires are 235/35-19 front and 305/30-19 for the rear with a difference of just 2.9% larger in the rear. Life went sideways and I couldn't sleep.....
So being totally **** retentive I have just replaced my rears with a new set of 325/25R20 Michelin Pilot Super Sports. Also researching the forum I see the set up I am now running is kind of a 20" standard that is working well for the Turbos. Also with this setup my car now has a 2.4% diameter bias to the rear so it is very close to OE specs and should keep my front differential happy.
Ok, here is the question-- with the wider rear tires (going from 295mm to 325mm) plus my 18mm spacers my side wall is exactly even with the widest edge of the fender lip. I verified this using a weighted thread as a plumb bob and hung it straight down over the outer edge of the fender lip after driving the car around the block to normalize the camber. The stance looks awesome like this but---Is this going to rub the fender lip??
However- the wheels were obviously for the NB and not the WB so I got a set of 18mm spacers for the rear to correct the offset and 3mm in the front which looked great and life was even better.
Then I started reading where some guys have had front differential problems due to the tires not being matched properly for the AWD system. So the guy who owned the car before me had put on a set of Michelin PSS tires sized 245/30R20's up front and 295/30R20's in the rear. The overall difference in diameter with this setup is 4.6% larger in the rear and the OE recommended tires are 235/35-19 front and 305/30-19 for the rear with a difference of just 2.9% larger in the rear. Life went sideways and I couldn't sleep.....
So being totally **** retentive I have just replaced my rears with a new set of 325/25R20 Michelin Pilot Super Sports. Also researching the forum I see the set up I am now running is kind of a 20" standard that is working well for the Turbos. Also with this setup my car now has a 2.4% diameter bias to the rear so it is very close to OE specs and should keep my front differential happy.
Ok, here is the question-- with the wider rear tires (going from 295mm to 325mm) plus my 18mm spacers my side wall is exactly even with the widest edge of the fender lip. I verified this using a weighted thread as a plumb bob and hung it straight down over the outer edge of the fender lip after driving the car around the block to normalize the camber. The stance looks awesome like this but---Is this going to rub the fender lip??
