Bicycle Mechanics - Can tire wear indicate frame lack of true?

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fadedglory
03-04-08, 08:25 PM
I'm used to the rear tire wearing at a much more rapid rate than the front, particularly given my weight. With my new frame, it seems that the rear tire is wearing a lot faster than with previous bicycles. After about 1,000 miles, there is enough flat spotting that I'm about ready to change the tire out. In my old days of 10,000 mile training years, I can't recall changing the rear (clincher) tire out any more often than every 5,000 miles or so.
Maybe its just a particularly soft rubber compound, but it does make me wonder if there could be some misalignment of this frame which causes increased rear tire wear. Is that a common finding with a poorly aligned frame? Rear wheel is well centered between the stays with axles hard against the rear of the dropouts, FWIW.
Thanks
Are the dropouts the no-brainer vertical type or the forward facing kind-of-finicky horizontal type? In either case, I think you would notice wheel misalignment from an out of true frame or off-center wheel during no-hands riding (just watch which way the bike likes to turn).
What tires are you running?
EDIT: You did say "hard against rear of the dropouts" so I guess they are horizontal. However these are more likely to be non-parallel than vertical dropouts. If your rear dropouts have adjustment screws, try tuning your alignment with them.
fadedglory
03-04-08, 09:06 PM
The dropouts are vertical, the bike tracks true hands free. The tires are the Performance Forte Kevlar Evolution ETT folding bead. They are durable and cheap and I've ridden these for years, though they have changed in appearance over time, so I wouldn't bet the rubber compound has stayed the same.
This is also by far the stiffest frame I've ever ridden, I wonder if that puts more lateral force on the rear tire, so causing faster wear?
JiveTurkey
03-04-08, 09:43 PM
Have you gained much weight since the old days of 10,000 mile training years?
fadedglory
03-05-08, 06:25 AM
Have you gained much weight since the old days of 10,000 mile training years?
Yes, quite a bit. :(
operator
03-05-08, 06:41 AM
Problem solved.
San Rensho
03-05-08, 06:57 AM
The rear tire always wears much faster than the front, especially if you are running high pressure in the rear. I will wear out 3-4 rears before I wear out the front.
fadedglory
03-06-08, 07:30 AM
Problem solved.
Hmmm. 500% increased tire wear for a 20% increase in weight. Doesn't sound like good science to me. In any event, the increased weight as a cause of dramatically increased wear would be intuitive, and a diagnosis of exclusion - rule out other causes first.
Maybe the tyre manufacturer has changed to a softer compound, or it could even be that you got a one off bad tyre. Unless you had a huge weight gain since you were last riding, I can't imagine that it would reduce the life of the current rubber by very much.
Is the bike new? Does it have a much more powerful braking system on the rear wheel than you used to have? It may be that with extra weight and a possibly more powerful brake, you could have worn it out through braking. I'm casting about wildly here - clutching at straws maybe...
Bill Kapaun
03-06-08, 11:47 AM
I would think if anything was misaligned, you would show a continuous wear pattern that wasn't "centered" on the tread.
I would think if anything was misaligned, you would show a continuous wear pattern that wasn't "centered" on the tread.
+1
"Flat spotting" sounds like wear from braking or possibly a defective tire.
1000 miles isn't much for a rear tire, 5000 miles sounds like more than normal for a rear tire.
Be sure to inflate the tires fully before each ride.
Al
Albinus
03-06-08, 06:27 PM
The rear tire always wears much faster than the front, especially if you are running high pressure in the rear. I will wear out 3-4 rears before I wear out the front.
Actually... in my experience with tyres (both on bikes and cars), higher inflation pressures actually help to preserve tyre lifespan. My tyres wear much faster (and it requires more effort to move) if pressures are lower than usual. Agreed on the 3-4 ratio though - and always keep the good tyre on the front! :)
I would think if anything was misaligned, you would show a continuous wear pattern that wasn't "centered" on the tread.
I would have thought so as well. Flat spotting sounds awfully like the rear wheel has locked up at times.
For more info regarding flat spots and worn tyres, why don't you head over to the fixed gear forum? Those brakeless doods would probably be lucky to get 1000 miles out of a rear tyre... :D
operator
03-06-08, 07:00 PM
1000 miles? More like 10 if i'm skid stopping everywhere.
mark9950
03-06-08, 07:16 PM
1000 is about right for a rear tire.
fadedglory
03-06-08, 07:30 PM
I shouldn't have used the term "flat spotting". The wear is even circumferentially, and doesn't predominate on one side of the tire or the other.
I'm starting to think changes in tread compound are a likely contributor.
Thanks for all the ideas.
matthew_deaner
03-06-08, 08:03 PM
1000 is about right for a rear tire.
1,000 is not normal wear for a rear tire unless you're brakeless or are running race-day tires (i.e. Michellin Pro2Race Special Edition, some veloflex models; etc). 2,000-4,000 is more realistic, depending on tire selection, terrain, and riding habits.
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