How to keep from cutting tires...

[ccallana]

Twice now, once on each side I've noticed the edge of my front tire cut and the edge of the fender bent down.... Seems like it's bottoming out in a hard corner.. can't keep trashing my tires like this ...

Do I just need to roll the fender back more? Stiffer roll bar? Bigger torsion bars? Raise the front up? For the most part it's all stock... Slightly lower ride height...

[ccallana]

[A930Rocket]

The problem is one or more variables: tire width, wheel offset, ride height, soft suspension, etc.

You’ll definitely need to roll the fenders back up to the stock location, or the tire will keep catching on it. I would do a search and maybe watch some YouTube videos on how to roll it. You might be able to take a wood bat and slowly roll it up. Take your time, as you don’t want to break the paint. Maybe a little heat might help while you roll it. I’ve got an Eastwood fender roller, but I had no luck using it on my E46 rear wheel fenders.

What size tires and wheel width/offset do you have?

What and how old is your suspension… shocks, t-bars, sway bar, etc? If it’s stock, original and or worn out, you might want to replace it for stiffer parts that work together, for the type of driving you want to do… street, track, etc.

If you want to keep your car stock, I wouldn’t roll the fenders totally flat, because it would be hard to unroll the fenders.

[ccallana]

Did new Elephant stock rubber bushings all the way around earlier this year, new stock sized torsion bars. Stock sway bar as far as I know. Did not replace shocks ... rears I have paperwork that they were replaced right before I bought the car - but no idea on the fronts... Tires are 205/55 16s 7", 23.3

[Bill Verburg]

Originally Posted by ccallana

Did new Elephant stock rubber bushings all the way around earlier this year, new stock sized torsion bars. Stock sway bar as far as I know. Did not replace shocks ... rears I have paperwork that they were replaced right before I bought the car - but no idea on the fronts... Tires are 205/55 16s 7", 23.3

Generally, that wheel/tire set will fit but it's very tight at the lips, as you found out.

Things that will alleviate and solve the issue.
1) use a bit more neg. camber
2) use a bit higher ride height
3) roll or even better trim the inner lip.
4) nominally the same size tires don't physically measure out the same, use a tire w/ a narrower tread width which usually provides a bit more shoulder room.
5) use a 205/50 tires which will be shorter and provide more room
5) stiffer t-bars

[ccallana]

Thanks for some suggestions...

Won't adding negative camber wear out the tires faster/unevenly?
Ride height is doable, but I like the look where it is (although I keep scraping the tow hook)
Rolling seems like the simplest option... don't really want to cut it off though...
I think these Bridgestones already have a pretty narrow tread, but I'll look into that...
Not many options in a 205/50 in a "sports car" tire - most I see are 87 load rating...
Stiffer t-bars going to roughen up the ride some I imagine.. and to balance would have to change the rears too

I'll work on bending the lip back some, hopefully that alleviates the issue for now..

[tobluforu]

Be very careful when you roll the fenders. Knowing the history of the car is key, make sure there isn't any filler in that area. Heat is your friend if used right, in other words, don't roll the fender when its frickn cold out, and use a hair drier or heat gun, with caution. Rent a roller, or if you have guts, get the bat out.
People cut them because it gets you a tad more room, plus if you drive in the rain, etc. Moisture, etc. can accumulate in that lip.
Camber: I, as well as others run lots of camber and really, I don't care if I have to rotate the tires more or replace them more often. But if this is a daily driver, then I get it.
Scraping on the tow hook, how low is this car cause my car is really low and I never scrap that. But then agian, the supension on my car is stiff.

[Glenfield]

Also, be careful with paint cracking if you role fenders and apply heat. If you trim, you compromise some structural support. If you flatten, you create a pocket for corrosion.

[silverlock]

Originally Posted by ccallana

Thanks for some suggestions...

Won't adding negative camber wear out the tires faster/unevenly?

Sure, but your alternatives are to raise the ride height, fit tires with shorter sidewalls (even within the same sizing), roll the fenders more, etc. A little more negative camber improves turn-in and cornering grip, so it's always a matter of trade-offs. I run -1.8 deg on the fronts and it's not like I'm losing thousands of miles of tire life vs. -1.3 deg or something.

For context: I run 205/55R16 on 7" fronts on my SC at the previously stated -1.8 deg camber. Tires are Yokohama AD09s, which are ~.1" shorter in total diameter vs. your 205/55R16 Potenza Sports, but .1" wider. I've only had them rub on the fenders once in > 5k of aggressive driving when I hit the bump stops hard mid-corner with a lot of steering angle :-)

[WMichelsen]

Plenty of other expert advise in this thread and on this topic.

I'll just say that I run 205/55-16, "standard" offset 7x16 Fuchs, on my '87 front. Mine is lowered to "Euro" spec, has a street alignment, and is otherwise mostly stock.
My fender lips are rolled, 180-deg up, but not to the point they touch the fender inside, so I don't see them trapping water.
Since rolling the fender lips, I have never had tire contact.

I suppose there's a chance fender/tire clearance may differ between cars. Maybe my fenders are pulled out more? No damage history, just hand-made car differences?
Anyway, just offering up a data point.

[Bill Verburg]

Originally Posted by WMichelsen

Plenty of other expert advise in this thread and on this topic.

I'll just say that I run 205/55-16, "standard" offset 7x16 Fuchs, on my '87 front. Mine is lowered to "Euro" spec, has a street alignment, and is otherwise mostly stock.
My fender lips are rolled, 180-deg up, but not to the point they touch the fender inside, so I don't see them trapping water.
Since rolling the fender lips, I have never had tire contact.

I suppose there's a chance fender/tire clearance may differ between cars. Maybe my fenders are pulled out more? No damage history, just hand-made car differences?
Anyway, just offering up a data point.

for the universe of 205/55 x16 tires that I have in my dB the metric for the shoulder clearance ranges from .771 to .952, bigger means a blockier tire shoulder w/ less clearance at the lip
Pirelli P7 Cinturato is .771
Dunlop Direzza ZIII is .952

all 4 BS Potenza variants are clustered @ .833 to .845

there is some variance from car to car but I haven't run into an irreconcilable difference for that tire size on that wheel

[Bill Douglas]

I gently warmed mine up with a hot air gun then rolled a baseball bat in there. I also run Potenzas and no rubbing. Actually I have the 16" X 7 Fuchs on the front and no problems. The hot air makes the paint less likely to crack.

[GH85Carrera]

Simple, buy tires that fit.

[ccallana]

Originally Posted by GH85Carrera

Simple, buy tires that fit.

These are stock sized tires nothing out of the ordinary

Although this chassis came with 15" 195s on the front I believe...

This is a very standard set up from what I've seen... just maybe the ride height is set a bit low and/or things are too soft for some of the driving enthusiasm...

[Bill Douglas]

Originally Posted by ccallana

These are stock sized tires nothing out of the ordinary

Although this chassis came with 15" 195s on the front I believe...

This is a very standard set up from what I've seen... just maybe the ride height is set a bit low and/or things are too soft for some of the driving enthusiasm...

They are exactly the same tire as I have, and mine don't rub. In fact I'm using 16 x 7" up the front instead of 16 x 6". So the problem is something else.

While it's parked there is a big gap between the tire and the fender, so there should be no rub. I'm wondering if the shocks have gone soft and the fender is bouncing down too low and hitting the rubber.

[WPOZZZ]

Originally Posted by tobluforu

Be very careful when you roll the fenders. Knowing the history of the car is key, make sure there isn't any filler in that area. Heat is your friend if used right, in other words, don't roll the fender when its frickn cold out, and use a hair drier or heat gun, with caution. Rent a roller, or if you have guts, get the bat out.
People cut them because it gets you a tad more room, plus if you drive in the rain, etc. Moisture, etc. can accumulate in that lip.
Camber: I, as well as others run lots of camber and really, I don't care if I have to rotate the tires more or replace them more often. But if this is a daily driver, then I get it.
Scraping on the tow hook, how low is this car cause my car is really low and I never scrap that. But then agian, the supension on my car is stiff.

If you rent/buy a roller,make sure it has the adapter for a larger bolt circle. Most max out at 5x120 or so, and you need it to be 5x130. I found out the hard way. if rolling, keep even pressure, or your fender can bow outwards.

[proporsche]

this rubbing on fender in your case is strange..i have on mine past 29 year front 205/55/16 Continental Conti in 8th-951 -offset i have never experienced any problem-the rear is 9th 951 .I did not rolled the fender at all..

[76FJ55]

Originally Posted by proporsche

this rubbing on fender in your case is strange..i have on mine past 29 year front 205/55/16 Continental Conti in 8th-951 -offset i have never experienced any problem-the rear is 9th 951 .I did not rolled the fender at all..

Can you provide that actual offset numbers for those 8" and 9" 951 wheels? seems that depending on year of 944 there is some discrepancy as to what the offset may be.

[proporsche]

76fj55..i am not expert on those measurements Bill Verburg is -i believe the 8th+9th are 23,3..
Would have to remove the rims and look;-)

Ivan

[porsche930dude]

Is your leg pic the ride height? Because that is very high. Mine is tucked and not a problem. I think they are cut down to about 1/2 the width i will have to check. The bending is happening when you are turning hard over off camber like going up in a driveway.