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Registered
Join Date: Jul 2006
Location: Charlotte, NC
Posts: 1,964
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Rear tire "scalloping"...
Not sure if the correct term is "scalloped" or "feathered". At any rate, both rear tires are showing the same wear pattern. I haven't had the car long, and have been sorting out a few things before I start driving it regularly, but have started to drive it more now. I notice at speeds > 70ish, I get a wobble. Hard to tell if it's in the steering wheel (front) or if it's the rear of the car. Maybe the whole thing. I figure I'm going to be spending some time this winter updating some suspension bushings, front and rear. The car ('81sc) does have quite recent rims on it (993's perhaps), with decent size adapters - no, I don't know if they are hub centric yet. Perhaps my wobble issue (they are about 1.25" adapters at least).
Here is a pic of the rear tire. Not sure the pic makes in the wear on the inside apparent or not. It's like every other lug in the tread is worn more. I get this on my BMW in the front, and know I've got to take it in for an alignment (toe in off I think???). Is this simply an alignment issue?  Cheers, Todd
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'81 SC |
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09-08-2006, 12:12 PM
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"O"man(are we in trouble)
Join Date: Nov 2005
Location: On the edge
Posts: 16,452
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Most likely an alignment issue, a good shop can tell you if there is something more serious, a bent something or other.
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09-08-2006, 12:25 PM
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cycling has-been
Join Date: Sep 2004
Location: Jersey Shore
Posts: 7,243
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if you feel the shake in your seat, its the rear, if you feel it in your hands on the steering wheel, its the front.
wear condition looks normal for a lot of neg camber and a load of fast corners at speed
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73 911T MFI, 76 912E, 77 Turbo Carrera |
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09-08-2006, 04:25 PM
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Registered
Join Date: Jan 2002
Location: Long Beach CA, the sewer by the sea.
Posts: 37,840
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I'm pretty sure you're having a balancing issue and/or a rear toe alignment issue. Both can manifest themselves as tire cupping, depending of the type of tire and tread. Back when most tires were skinnier and the treads weren't as open as they are today, these problems were easier to diagnose. Lots more variables nowadays.
I think you can eliminate the shock as a cause since it looks new. Are those Continentals? |
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09-08-2006, 04:59 PM
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Join Date: Oct 2004
Posts: 15,612
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tire cupping I think is also called scalloping. It's caused by a wheel that is severly out of balance, or worn shocks. I agree with Milt.
Feathering is an irregular wear caused by bad alignment. Possibly worn suspension parts. |
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09-08-2006, 05:13 PM
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Registered
Join Date: Jan 2002
Location: SF Bay Area, CA
Posts: 1,861
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I had this on my Jetta when it was brand new. As soon as I swapped out the underdampened OEM shocks out for Bilsteins, it went away.
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09-08-2006, 06:58 PM
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Registered
Join Date: Jul 2006
Location: Charlotte, NC
Posts: 1,964
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Milt - yeah, those are pretty new Bilstien HD's. The tires are Kumho's actually... 255/45.
Like I said, I think I'll be updating some bushings, etc. and before that even, probably having the alignment and a good tire balance done.
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'81 SC |
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09-08-2006, 09:20 PM
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Registered
Join Date: Jul 2000
Location: So. Calif.
Posts: 19,910
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Feathering = toe wear. Too much of it, either in or out.
Sherwood |
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09-08-2006, 10:31 PM
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