tire rubbing after tire replacement

[Hnichols]

Hello everybody,
Would appreciate any insight on my latest issue:

Replaced all four tires at Tire Rack on Saturday on the way from Chicago to Massachusetts: Bridgestone R11s. The tires are wonderful, but: halfway into my trip (around Ohio) I noticed that the right front tire made contact with the fender when I went over a hard bump, slicing what I think are superficial grooves on the top outside side of the tire. Initially I thought it was simply a matter of a slight difference in the shape of the tire (the tires I replaced were the same size (205/55/16) with virtually no wear, combined with my low, euro-height. But: contact is only on one side (left side is fine). And to the naked eye it looks like the alignment is off -- the problematic right side looks like it's toeing out in comparison with the left. The problem, if anything, is getting worse.

Obviously I need to have someone check the alignment before the return trip. Since I had no alignment issues before the tire change, I'm wondering if they messed something up during the installation. One thing they did was jack the car up on one side instead of front to back, which is how the Porsche jacking point is supposed to work. But it was tilting on two wheels for a whole, about an hour: could that have messed something up?

If the TR people did something wrong, I'd take it to their local installer here on Cape Cod (Hyannis area). If not, I'll take it to someone who works with Porsches. So what do y'll think?

As always, thanks in advance!

[fintstone]

What tires did you have on it before? Tread width, section width and diameter varies from tire to tire in the same size. You have to compare these when changing tires.

Stiffer torsion bars or raising the rear height slightly would probably help if you want to run those. Some folks roll the fenders...but not my cup of tea.

[Oh Haha]

I read your other post about your trip.


How much extra weight in luggage/humans are you hauling?

The extra could have your front height a bit lower than usual. The new tires may be just a bit wider than your old ones and the combination might be your issue.

[Trackrash]

Wouldn't hurt to have your alignment checked and to make sure your ball joints, struts, wheel bearings and bushings are tight.

[Hnichols]

Thanks the responses.

Fintstone: Bridgestone Potenza Pole position -- I forget the exact model # -- but the same size. Yes, they could very well be a touch wider and/or higher. With the already lowered suspension, that might explain some rubbing. But why only one side? And why would it get worse the more I drove?

Oh Haha: I didn't think about the added weight. But on the 100 mile drive from Chicago to South Bend I had the same cargo -- with a full tank of gas -- and no issues. And not much fits in the front trunk anyway. So I don't think it's that, or only that.

Trackrash: Yes, I think you're right. I'll definitely doing that. I am really just trying to rule out the possibility that someone screwed something up with the installation. I don't want to hold someone responsible for something -- particularly if I have to buy another front tire -- unless I have reason to.

[fintstone]

Hand built cars are not always exactly the same on both sides. I had the same problem...just one rear tire. I'm not positive what fixed mine as I had new torsion bars and struts put in at the same time...then of course alignment and corner balance. Could just be that you are a bit out of alignment or your strut on that side is giving out. It doesn't take much. You can give the alignment a rough check with a string as described on here somewhere if you search. A bad strut can get worse as you drive due to heat if it is dry.

Not much difference in RE-11s and any of the Pole Positions...unless you got the RE 11A which has a 7.8 inch tread width as opposed to a 7.2 on the RE-11, 7.1 on the RT 970 Pole Pos, 7.2 on the 960 Pole Pos or 7.6 on the S-04 pole pos. Sectional width and diameter are the same.

[javadog]

Unless you have 7" front wheels, rubbing should not be an issue. There's nothing that the Tire Rack could have done to screw up the alignment when fitting the tires.

My guess is that your car is below "Euro" height, as are 90% of them that people think are at the correct height. Your car left the factory with the same front height that every 911 had, as there was no difference in the front height settings that year. If your car has been lowered, it's below the correct height.

It's not uncommon for two tires of the same nominal size the have different section widths, shoulder profiles, etc. Just get an alignment done. Consider raising the car back up some. I'd get it corner-balanced too, as that's an important part of a proper alignment.

JR

[wayner]

The good news is the it is really easy (even at the side of the road) to crank a few turns into the front torsion bar adjusters to get a bit more height!

[gtihop]

Make sure the front rims are on the front with the correct tires and the rear rims are on the rear. I've seen it many times before with different width and offset wheels!

[Jcslocum]

Lifting the car on one side will not damage the steering or it's geometry. Now the oil cooling lines, that another story!! Please check to make sure they didn't crush them.

It sounds like you wheel alignment might be off up front. Not having the right camber or toe will allow the top of the tire to hit the inside edge of the fender. These adjustments are made at the top of the strut in the frunk for the caster/camber and the toe is done under the car at the tie rod ends.

A quick FRONT end alignment check and realign should help up front and can be done a pretty much any shop with good equipment. The rear end alignment should be handled by a specialist porsche shop as the local "tire" shop will go out of their minds trying to do it with no experience and you will leave unhappy.

Good luck!!!

[Driven97]

As others have said, rub on only one side is not uncommon on the 911. When I temporarily had to go to the OE camber plates when an aftermarket one failed, the LH on my car rubbed slightly, only on large bumps.

I'd bet those RE-11 are indeed slightly wider than what you had on there. I highly doubt Tire Rack goofed anything up during a change, there's not an easy way to.

As far as the "changing" problem, did you perchance have an empty gas tank at first and it's worse with a full gas tank? 21 gallons of gas = over 160lb, which is enough to change the height up front especially on soft OE torsion bars.

Solutions are (and not all of these are good solutions):
- Raise ride height
- Add negative camber
- Roll / cut fender lips
- Use stiffer torsion bars to decrease bump travel
- Get narrower tires or increase wheel offset

That said, I ran wide for their size 225s on the front of my car under untweaked fenders, so 205s should fit super easily.

[jwakil]

One thing they did was jack the car up on one side instead of front to back, which is how the Porsche jacking point is supposed to work. But it was tilting on two wheels for a whole, about an hour: could that have messed something up?

--For the old 911s, when you use the normal jack in the jackpoint , it raises one side at a time.

[Hnichols]

Thanks everybody. I think the problem is solved: I tightened the height adjustment bolts 3/4 a turn to give myself a tad more clearance, then brought it to a shop for a front end alignment. Unfortunately I wasn't able to talk to the tech who did the work, but it looks like the wheel was "toeing out" and the alignment straightened it out. (I have a suspicion that they adjusted the toe and that's it, but the car drives well -- certainly enough to get me back home). In Chicago I might consider having a complete alignment done by someone who knows old Porsches.

How it got knocked out of alignment is still a mystery. Maybe the crappy Indiana tollway.

[SiberianDVM]

When I changed from Dunlop Direzza DZ102 to RE-11A tires on my M3, which was running 1 size over, I had to drop down to OEM size because of a rub, so the RE-11A tire is indeed wider than some others.

Great tires though. I run them on the M3, the 911, and the Supra ChumpCar.

[vansicklenmi]

All tire sizes are not the same! Even within the same brand and the same pattern ACTUAL tread width and section widths ( that's what the "205 mm" is ..) can vary significantly!

I just out new Hoosiers on my Carrera in the exact same size on the exact same wheels and the news ones rubbed! They were as much as 1" wider in tread width.

Just remember, if you already have close tolerances, a different tire may not fit. The new BS Potenza RE71s and RE11 are " extreme " track/street tires so the tread width can be "optimized" for ultimate grip. Be careful. A tire that has slight rub on the street can quickly destroy a fender and tire in a high corner load situation.

Oh yeh, I was the Bridgestone UHP for many many years!

[vesnyder]

Nobody mentioned rolling the fender. I had a similar problem and rolled the drivers side fender. Worked great.

[MichaelN]

I have an '81 SC, European ride height, good alignment and I was running Toyo TR1s 205X55X16 on the stock 6" rims in the front. I replaced them with same size Bridgestone R11s (purchased from Tire Rack) and the next time I went autoXing I they immediately rubbed on the fender lip taking a nice little gouge out of the outside of the tire (left side only) near where the tread meets the sidewall. I later had the same problem on a back road when I encountered a bump cornering hard. I think your experience is typical - those R11s simply have a wider profile than most. I ended up rolling the fender lip (myself) and the problem was solved.

[DRACO A5OG]

Size stated on the side wall is matter of manufacturer's interpretation



Conti vs Goodyear with same dimension on the side wall