Rear tire rub

[redstack]

As you can see, I have the 17" cup wheels, running 255 /40/17 which is the tire rack optional size.
In the pic it shows the tire fitment. The brand new RE-11 rub more than the old michelins did.




Suggestions?

1. Roll fender, seems like it might help, but it leaves rubber on the inside of the fender, seems like it would be a partial fix. Luckily it doesn't seem to have damaged the tire, Yet, not a big gouge anyway.

2. See if it's possible to reduce the rear spacer thickness. I imagine the concern then is rubbing on something on the inside of the wheel, maybe oil lines?

3. Increase ride height?

4. Increase torsion bar size to reduce roll, but that would have bad effect as far as oversteer concerns right?

I bought the new tires just days before leaving for work, so didn't have time to jack it up and check spacer fitment and such.

[redstack]

Just a funny story. I wrote a post about taking friends to dinner and how the girls in the back seat made it hard to shift into first. Well with a full load onboard, it also increased the tire rub of course. But what was really funny was that the rub increased after dinner, I swear we didn't eat that many Oysters and that much Fried Mullet.

[matt f]

More negative camber may help as well as rolling the fenders.

Matt

[JAR0023]

My unprofessional opinion? Car doesn't look that low. Your 255s can't be all that much wider that my 245s. In the "action shot" your wheels do look to me to be sitting wider than my car. I have 245 RE-11s on 9" Fuchs. I'd be looking to reduce spacer size. Next step is to crawl under there and see how much room you have on the back side. -J

[redstack]

@Matt I'm always a fan of more negative camber. Old hard tires really understeered, so I thought that more front neg camber would be a good deal. I was thinking that it was about time to consider a alignment, what with the new tires and all.

[seebobgo]

Do you really need a 255? Seems like a 245 would be enough tire for that car.

[Arne2]

+1 on reducing spacer size. How wide are those rear wheels? If they are 9" wide, I'd try to get the effective offset close to 15mm, same as a 16x9 Fuchs. I know of a local car with 17x9 ET15 Euromeisters with 255 RE11 on the rear, no problems.

To figure the effective offset, subtract the width of the spacers in mm from the actual offset of the rear wheels. For example, if the wheels are ET45 and the spacers are 2" (50mm), 45 - 50 = -5. That would move the wheels to the outside about ¾" further than the factory 9" wheels. In that case, you'd want 30mm spacers to get the total to 15.

[redstack]

So the size is 9jx17 ET 55 I believe it says there.

[redstack]

"To figure the effective offset, subtract the width of the spacers in mm from the actual offset of the rear wheels. For example, if the wheels are ET45 and the spacers are 2" (50mm), 45 - 50 = -5. That would move the wheels to the outside about ¾" further than the factory 9" wheels. In that case, you'd want 30mm spacers to get the total to 15."

OK ET 55- 50 because I'm guessing from what I saw, that they are about 2" spacers would equal +5 that would mean that I need 40mm spacers, if they don't cause any inside rubbing.

BTW the new RE-11 required much less weight to balance, less than an oz in most cases.

[Bill Verburg]

Originally Posted by redstack

So the size is 9jx17 ET 55 I believe it says there.

You should have no problems if you use a thinner spacer

9ET15 will provide a room on both sides of the tire, so if you use a 40mm spacer on 9ET55 you are golden.

If you want to push things the absolute max for back space w/ SC/Carrera chassis is 152.4mm, the absolute max front space is 114.3mm. Anything w/i than envelope will be fine w/ a 255/40 x17 tire, At the extreme edge of the inner envelope you do need to move the oil line and shave the trailing arm bolts.

For comparison I use 9.5ET17 and 255 to 275 tires if you use 9ET15 wheels with 255/50 tires the wheels will have 2.35mm more room on the outside and 10.35mm more room on the inside than I have. The tires will have the same additional clearance. I have massaged the lips for additional clearance but w/ 9s it shouldn't be necessary. If you want more room at the lips just use a slightly thinner spacer.

[redstack]

Bill and Arne,
Thanks for the assist. I'm not sure right now what size and brand spacers I have, but they are thick for sure. I'm guessing that the easiest thing would be to have either a buddy or a shop turn them down to 40mm. Then if there is still a problem, roll the fenders and maybe put in a little more negative camber.

Bill, are there given alignment setups for autox or track days? The miata crowd had several standard ones, that everyone knew.

[JeremyD]

Turn the spacers - you'll have plenty of room - I've stuffed 275/17's on a Carrera -

I've also used stacks of washers on wheel lugs to get me the desired wheels depth - then had a set of spacers turned or ordered. Don't drive with the washers.

[boss11]

+1 on negative camber

I had really bad rub in rear left guard when I fitted my 17x9 euromeisters with 255/40 tyres, to the point where it was smoking after 100m of test drive, by the time I turned around and got home (400m or so) it burnt the paint on the very outer edge of the guard

the rear guards don't have a "lip" on the inside like the front ones do, so it is not as simple as just folding it up. I tried rolling rear left guard on mine, it did pull out a bit, however I stopped as it was about to change the angle of the very outer edge of the guard and I didn't want the rolled guard look that you see on JDM style rice crackers.

I measured fender heights and that corner was a bit lower than others, I was able to raise it by adjusting the eccentric screw on the spring plate. With massaging the guard and raising the height I was able to drive to get an alignment and asked them to dial in more negative camber. I think they set it at -1.07

now with a passenger and "spirited" driving every now and then I get residue of tyre shine mixed with rubber on the inner guard

next alignment, i'll be asking for another half degree of camber

[911pcars]

Originally Posted by JeremyD

Turn the spacers - you'll have plenty of room - I've stuffed 275/17's on a Carrera -

I've also used stacks of washers on wheel lugs to get me the desired wheels depth - then had a set of spacers turned or ordered. Don't drive with the washers.

JeremyD has suggested a more reasonable strategy than buying new wheels. Another strategy is to remove the spacer then inspect/measure the available space inside and outside, then proceed accordingly.

I'd be surprised if the fender lip interferes with the tire. That's more of a front end issue. Excessive rear track will cause the tire to rub on the inner fender about 1.5" above the arch caused by some combination of suspension compression, vehicle speed and side G-force (cornering). This will be confirmed by observing a half moon burn mark on the paint

Don't feel compelled to increase ride height or increase torsion bar size to create more space. That will bite you the first time you meet that special dip in the road or decide to max the cornering speed in some distance future. Besides, it looks high enough already.

Sherwood

[moneymanager]

While you're following all these suggestions be careful not to burn the paint off the fender(s). It only takes a few minutes.

[redstack]

Thanks Guys, so far it's been the tire leaving rubber, no burnt paint. But now I have some good leads, starting with the spacers, then negative camber.

How much negative camber can you get in the rear end of these cars? I would think that you wouldn't want more than -1.5 or so.

[redstack]

Jeremy I like the idea of using washers to get a template for how thick a spacer you can use.

Thank goodness the fronts fit fine.

[redstack]

Jeremy I like the idea of using washers to get a template for how thick a spacer you can use.

Thank goodness the fronts fit fine.

[JAR0023]

Originally Posted by redstack

Thanks Guys, so far it's been the tire leaving rubber, no burnt paint. But now I have some good leads, starting with the spacers, then negative camber.

How much negative camber can you get in the rear end of these cars? I would think that you wouldn't want more than -1.5 or so.

I'm running -1.2 on the rear of my car and it's a daily driver; meaning I erred on the side of long tread life and even wear over ultimate grip. -1.2 is at or close to the factory specs. -J

[911pcars]

To make my point clearer, use suspension adjustments to improve handling characteristics, not to provide clearance for tires. However, if you want raise the ride height, increase the TB size and/or introduce more negative camber for justified reasons anyway and those adjustments also allow uninterrupted wheel travel, go for it and kill two or more birds with one stone.

Sherwood