Wheel size and spacer for 7R ET49 fuchs

[A_Alfa]

I want to put my 7R ET49 fuchs into the rear of my 1972 911E.

I currently have standard ET36 fuchs and 195/65/15 Continental Premium Contact 2 tyres front and rear.

I am deciding between 215/60/15 and 205/60/15, I would prefer 215 size.

My car has standard flares and is a little bit lowered vs european height, I do not want to modify the flares.

Did some research and:

A. The 215/60/15 is 0,8% larger and considering also the ET change the edge of the new tyre will be 23mm closer to the inside of the wheel well and suspension components, and 3mm further in from the edge of the bodywork.

B. The 205/60/15 is 1,1% smaller and considering also the ET change the edge of the new tyre will be 18mm closer to the inside of the wheel well and suspension components, and 8mm further in from the edge of the bodywork.

My Porsche mechanics says 215 will work with 7mm spacers.

What are your opinion experience with this change, will 215 work or will it rub with the 7Rs?

thx. Arturo

[jameshtaylor]

Tires of the same size can actually be a few millimeters different in width. One brand might work where another won't. But measure your existing clearance. If you will need 23mm clearance on the inside with that spacer, and you have 30mm, all should be well. There remains the possibility that the 215 will rub on the outside because of your lowering. Probably best to mount the tires, glue a bit of sponge or something similar to the inside of the fender up 30-50mm from the lip and drive carefully around the block. Check the sponge. If ok, take another slightly more vigorous ride and check again. Keep checking till you know the tire isn't going to rub. If it does rub, you need to raise the body, or add some negative camber, or get smaller tires or a thinner spacer (if you have space to the inside).
There will need to be some testing to be sure you're ok.

[304065]

Arturo with a non-flared narrowbody LWB the conventional wisdom is to use a 225 tire with a 10mm spacer for ET -39. Whether it rubs is also a function of how much negative camber you are accomodating in the rear.

[72Group4]

good advice from jameshtaylor.

From experience in trying to use 7Rs or 8" rims at the rear of my narrowbody '72 - I ended up road testing a series of spacer and camber combinations to make sure there wasn't a rub. What looked ok on the hoist wasn't always the case when we road tested it. I used a combination of chalk on the tire and cloth tape against the body (both fender lip and inside frame) to test it but a sponge may also work.

[60surfer]

I am also about to put 7R rims with 215/60-15 tires (Avon CR6-ZZ) on a 1970 Coupe. The final test will be done next week but a first trial on another car showed that with an 11 mm spacer the tire got very close to the inner fender, while with 15-18 mm is would rub the outer fender. However, as said before this is closely related to camber and individual body tolerances.

[gled49]

I installed the factory +10mm wheel studs, the factory 7mm wheel spacers and 205/60 tires. Not the biggest tire combo but it worked great. Also no need to remove dust covers on front struts. Gled