Why a 16x7 911SC rear wheel will not work on an earlier car
07-12-2012, 11:28 PM
#1
Rennlist Member
Thread Starter
Join Date: Jun 2012
Location: Aloha!
Posts: 227
Likes: 0
Received 0 Likes
on
0 Posts
Why a 16x7 911SC rear wheel will not work on an earlier car
So, I spent the afternoon partially dismantling my rear suspension to lower it a little and to take a few measurements. I have a 1975 911S with 16x7 rear wheels off of an '85 or later 911. They have an offset of 23.3mm
Right now, the car has the rear end raised for tire clearance (this is how I bought it), and it has 225/50/16's mounted in the rear. I moved the suspension one spline on the outer torsion rod to lower the rear end, to achieve exactly the ride height that I want, which isn't really all that low...
I adjusted the rear suspension for maximum negative camber (only to see what that would get me in terms of additional tire clearance), and then bounced the car several times. I chalked a line where the rear fender lip touched the tire. Then drew another chalk line where the lip would touch the tire if I rolled the fender lip...not much a difference really.
The section width on a 225 tire is too wide, and it will simply never fit under the stock fender- this I already knew.
But even a 205/50 tire will not work on this rim, partially because the 7" rim extends further outboard than the 6" rim, but also because the 7" rim produces a mounted tire section width that is wider than a 6" rim would produce...
First picture is how I bought the car.
Second picture is the car lowered with max negative camber.
Third picture are the two chalk lines. (sorry for the sideways pic's- every time I upload an iphone pic, it gets rotated in the posting)
The inboard chalk line is where the inside of the fender lip hits now with max negative camber dialed in. The outboard line is where it would hit if I rolled the fender. A 205 tire might bring the outer chalk line in another 10mm (half of the 20mm section width difference between a 225 and 205 tire), but that still won't be enough to clear a rolled fender lip- I've got more than 20mm of tire tread outboard of the chalk line right now... there is no way that I will be able to run 205 tires on the rear with these rims.
Is anyone interested in buying a pair of rear 16x7 Fuchs? [edit]: I found a pair of 16x6's for the rear.
Posting this so that it may help others not to make the same mistake....
Apparently, there are 16x7 wheels that do not have a 23.3mm offset, and those might work just fine. But my wheels do not work!
Right now, the car has the rear end raised for tire clearance (this is how I bought it), and it has 225/50/16's mounted in the rear. I moved the suspension one spline on the outer torsion rod to lower the rear end, to achieve exactly the ride height that I want, which isn't really all that low...
I adjusted the rear suspension for maximum negative camber (only to see what that would get me in terms of additional tire clearance), and then bounced the car several times. I chalked a line where the rear fender lip touched the tire. Then drew another chalk line where the lip would touch the tire if I rolled the fender lip...not much a difference really.
The section width on a 225 tire is too wide, and it will simply never fit under the stock fender- this I already knew.
But even a 205/50 tire will not work on this rim, partially because the 7" rim extends further outboard than the 6" rim, but also because the 7" rim produces a mounted tire section width that is wider than a 6" rim would produce...
First picture is how I bought the car.
Second picture is the car lowered with max negative camber.
Third picture are the two chalk lines. (sorry for the sideways pic's- every time I upload an iphone pic, it gets rotated in the posting)
The inboard chalk line is where the inside of the fender lip hits now with max negative camber dialed in. The outboard line is where it would hit if I rolled the fender. A 205 tire might bring the outer chalk line in another 10mm (half of the 20mm section width difference between a 225 and 205 tire), but that still won't be enough to clear a rolled fender lip- I've got more than 20mm of tire tread outboard of the chalk line right now... there is no way that I will be able to run 205 tires on the rear with these rims.
Is anyone interested in buying a pair of rear 16x7 Fuchs? [edit]: I found a pair of 16x6's for the rear.
Posting this so that it may help others not to make the same mistake....
Apparently, there are 16x7 wheels that do not have a 23.3mm offset, and those might work just fine. But my wheels do not work!
Last edited by MillenniumFalcon; 07-13-2012 at 06:29 PM.
07-12-2012, 11:43 PM
#2
Rennlist Member
Seems odd ,I could swear 7's either 15 0r 16 should fit ,If I didn't know any better I'd say that is likely a
944 offset 7x16 which apparently has more offset to the outside,see if there is a 951 serial number
possibly? Bert
944 offset 7x16 which apparently has more offset to the outside,see if there is a 951 serial number
possibly? Bert
07-16-2012, 01:44 PM
#4
Rennlist Member
You will need to run 6" wheels or SC flares to run 7s. Or the Paris to Dakar setup that you had.
If you find Fuchs 7 x 15 "R" offset$$ they will fit.
AIRC I couldn't even run 225/50x15 on the '70S without burning the paint off the fender curve.
http://www.ebay.com/itm/porsche-fuch...item2a14d3099b
http://www.ebay.com/itm/Porsche-Fuch...item2c66aadd37
If you find Fuchs 7 x 15 "R" offset$$ they will fit.
AIRC I couldn't even run 225/50x15 on the '70S without burning the paint off the fender curve.
http://www.ebay.com/itm/porsche-fuch...item2a14d3099b
http://www.ebay.com/itm/Porsche-Fuch...item2c66aadd37
07-16-2012, 03:44 PM
#5
Rennlist Member
Thread Starter
Join Date: Jun 2012
Location: Aloha!
Posts: 227
Likes: 0
Received 0 Likes
on
0 Posts
Just purchased a pair of 6" wheels from another member, and they are on their way.... Paris to Dakar- good one....
I'll be selling my 7" wheels as soon as I get the 6" wheels on my car.
Now that I'm going to be running 6" wheels in the back, I assume I can run 215/50/16 in the back no problem?? I already have 215/55/16 up front, and am trying to get away with only buying 2 new tires right now.
I'll be selling my 7" wheels as soon as I get the 6" wheels on my car.
Now that I'm going to be running 6" wheels in the back, I assume I can run 215/50/16 in the back no problem?? I already have 215/55/16 up front, and am trying to get away with only buying 2 new tires right now.
