Rear fender rubbing

[tdskip]

Hi guys - been distracted with "life" and other things to have to deal with but am finally getting a chance to get back to the 911. My car is a '74 with a 3.2 and I have an issue with fender rubbing that looks to be wheel travel related rather than side to side movement.

The last run I ran her aggressively was on a fast road touring event and I got fender blistering on both sides from where it tires appear to have made contact. She has 26mm rear bars and adjustable spring plates that I put on, and she was professionally corner balanced and aligned. Her rear shocks are Bilstein from about 10 years ago but have under 17k miles on them.

To prevent this from happening again do I "just" need to raise the ride height fractionally? I don't want to kill the ride quality but would a thicker rear bar help or is there another way I should be thinking about this?

Thanks - and best wishes to everyone on a happy Holiday season.

[pete3799]

What wheels and what size tires are you using?

[tdskip]

Originally Posted by pete3799

What wheels and what size tires are you using?

Hi Pete - sorry, that is pretty important info which I neglected to provide. Sorry, not enough coffee yet.

She has 205/55/16 all the way around currently.

I have a set 16x7 (951) wheels that I have not mounted yet.

[Flat6pac]

You need the 25.5mm Carrera bars in the rear for the extra weight in the rear from the aluminum engine. The rear of the car is sagging and the Carrera bars will support the extra weight and handle the spirited driving minimising the rear bar travel.
Bruce

[tdskip]

Originally Posted by Flat6pac

You need the 25.5mm Carrera bars in the rear for the extra weight in the rear from the aluminum engine. The rear of the car is sagging and the Carrera bars will support the extra weight and handle the spirited driving minimising the rear bar travel.
Bruce

Hi Bruce - thanks for the response. Wouldn't the 26mm bars handle that already?

[Bill Verburg]

Originally Posted by tdskip

Hi guys - been distracted with "life" and other things to have to deal with but am finally getting a chance to get back to the 911. My car is a '74 with a 3.2 and I have an issue with fender rubbing that looks to be wheel travel related rather than side to side movement.

The last run I ran her aggressively was on a fast road touring event and I got fender blistering on both sides from where it tires appear to have made contact. She has 26mm rear bars and adjustable spring plates that I put on, and she was professionally corner balanced and aligned. Her rear shocks are Bilstein from about 10 years ago but have under 17k miles on them.

To prevent this from happening again do I "just" need to raise the ride height fractionally? I don't want to kill the ride quality but would a thicker rear bar help or is there another way I should be thinking about this?

Thanks - and best wishes to everyone on a happy Holiday season.

She has 205/55/16 all the way around currently.

I have a set 16x7 (951) wheels that I have not mounted yet.

The culprit is the combination of narrow rear fenders and tall tires

Since you haven't mounted the 7x16's(944 and 911 Fuchs in that size have the same ET) are we to assume that what is on the car are 6x16? or 911 7x16?

In either case a 205/50 would be shorter and less likely to blister the fender

[tdskip]

Originally Posted by Bill Verburg

The culprit is the combination of narrow rear fenders and tall tires

Since you haven't mounted the 7x16's(944 and 911 Fuchs in that size have the same ET) are we to assume that what is on the car are 6x16? or 911 7x16?

In either case a 205/50 would be shorter and less likely to blister the fender

Hi Bill - I believe she has 6x16s on her now. (Best picture of the current wheels - and believe it or not she was in far worse shape when I got her. Working on her reliability/driving dynamics rather than esthetics)

[Bill Verburg]

Originally Posted by tdskip

Hi Bill - I believe she has 6x16s on her now. (Best picture of the current wheels - and believe it or not she was in far worse shape when I got her. Working on her reliability/driving dynamics rather than esthetics)

Those appear to be 7s, again the 911 & early 944 7x16 have the same ET and will fiit the same, the difference is in room for brakes

You want a shorter tire

[tdskip]

Hi Bill - thanks for the thoughts. The current rims should have some sort of stamping where I can confirm their actual size, right?

I'm a 911 newbie and this xar was badly hacked so I've learned to not make ANY assumptions.

Thanks again

[ClickClickBoom]

Hey,
My '75 911 with the stock 2.7 and 205/50x16 all around rubbed. The stock t-bars were installed. Larger t-bars will indeed limit wheel travel, possibly enough to drive, but the fact remains, you have a clearance issue between the tire and body. Solution, narrower tires, solid struts instead of shocks to prevent wheel travel or trimming/rolling the fender to provide clearance. Your car should have no interference at any potential wheel travel. Common wisdom has been that the Middies like 21/27mm t-bars, and the 3.2 Carerra with 22/28mm as a starting point.
I rolled my fenders for clearance and many others have trimmed the lip, either will work.
Good luck
eric

[tdskip]

Thanks Eric - so it looks like I "get" to reindex the rear suspension again...

[PropellerHead]

A shorter tire will help a lot. The 205/55-16 is very tall. A 50 series will help significantly. Also, more negative camber will help. Last, a larger rear sway bar will help too.

If those items don't work, raise ride height and/or stiffer torsion bars.

Skinny tires are a last resort!

[tdskip]

Originally Posted by PropellerHead

Last, a larger rear sway bar will help too.

She doesn't have a rear bar at this point, should of noted that. Sorry.

So the idea being that better controlling lean will limited total vertical travel (except for a straight on significant impact/depression in the road of course)?

Sounds like the tires need to go in any case.

Thanks for the coaching.

[PropellerHead]

I ran a 205/55-16 on a lowered suspension without a rear bar. It rubbed significantly, even with 30mm torsion bars.
I added a sway bar (tarrett) and it improved significantly.
Then, shorter tires and some negative camber and no more issues.

[Bill Verburg]

Originally Posted by tdskip

Hi Bill - thanks for the thoughts. The current rims should have some sort of stamping where I can confirm their actual size, right?

I'm a 911 newbie and this xar was badly hacked so I've learned to not make ANY assumptions.

Thanks again

Yes, on the back of the spokes you will find something like this
Size, this one is a 9x15


part #, this one is a 911 8x16

[Dan J]

Bill, as usual, Is correct. Those are 16x7 wheels and unless you put a lot o rear bar- torsion and sway they will not work if you push the car
PS Merry Christmas fella's

[Bill Verburg]

Originally Posted by Dan J

Bill, as usual, Is correct. Those are 16x7 wheels and unless you put a lot o rear bar- torsion and sway they will not work if you push the car
PS Merry Christmas fella's

And to you and yours

[tdskip]

Hi guys - belated Happy New Year to everyone.

I pulled the existing rear wheels and they are 7jx16, as are the "new" ones sourced from a 951. Is there any advantage on running the 951 ones here to deal with rubbing, or are the offsets the same?

Baring any advantage from the 951 rims it looks like a rear bar and lower profile tires are the next steps? Sound right?

Thanks guys.

[will hung]

The 951 will only allow bigger brake options. The offset is the same as the 911 wheel. I'd try a rear bar, then lower profile tires, and then ride height.

[tdskip]

Thanks Will, appreciate the coaching.