Topica Loopframe_Guzzi Archive


Subject: RE: front front front front end problem end front end problem

Author: murp-@aol.com

Date: Aug 30, 2002, 8:13 PM

Post ID: 1710916684


John and others,
Today I had the back tire checked, and it too was perfectly balanced,
so I concentrated on the front wheel out-of-round condition. I fiddled
around with spoke tension a bit and was able to true up the wheel
slightly, although I think I'm still out by 1/16" or so. On the test
ride, however, the problem is so small as to be unnoticable unless
you're really looking for it. At any rate, it's close enough for me.
Thanks for all the suggestions.
Brian
'74 Eldo
'78 T3

John Prusnek wrote:
 Brian:
Based upon my one time experience with this, I'd say that it would. My
front tire started bouncing around 30-35mph, then smoothed out after
that. The tire was perfectly balanced, I even had the balance rechecked;

it was then that I noticed the runout since I was looking for a problem.
It was also at this time that I noticed that the manufacturing date
on the tires was 1971 (!). I figured that it was an old tire that sat
in one place for years and developed a flat spot- I think the bike was
stored for a long time before I got it. I should have noticed the age
and scrapped them in the beginning.
If your front end is bouncing around at speed and the tire's balanced
and the rim is round, what else could it be? I'm no physics major, but
I suspect that there's a bit of force happening at 30mph.
A friend of mine used to work for a tire company, he said that they
would occasionally chuck a mounted tire up in a lathe and trim the
outside to make it round. He was suprised at how much some tires were
out, some to the point that they went down to the casing, scrapped the
tire and started over again.

John Prusnek


 John,

My question now is this: would an out-of-round condition of 1/8" be
enough to cause this problem?
Again, all comments are appreciated.
Brian

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