Beat rim into true or not?

After a recent crash I have discovered a permanent bend in my front
rim, more of a single wave that extends about 1/4 of the way around the
rim. Laying the rim on the floor after disassembling the wheel, the
max out of true is ~1/4". There doesn't seem to be a kink in it,but
rather a smooth wave.

Would you beat on the rim with a rubber mallet or just bring it into
true with the spokes?

Oh, yeah, rim is Open Pro 36 spoke.

TIA

App

App wrote:
After a recent crash I have discovered a permanent bend in my front
rim, more of a single wave that extends about 1/4 of the way around the
rim. Laying the rim on the floor after disassembling the wheel, the
max out of true is ~1/4". There doesn't seem to be a kink in it,but
rather a smooth wave.

How wobbly was the wheel before disassembly? How uneven was the spoke
tension? If the spoke tension was very uneven, throw that rim away and
rebuild the wheel.
Why did you disassemble the wheel? Do you mean you unlaced it, or
loosened the nipples, or what? You can straighten rims by hitting them
with a mallet while the bent section is between two 2x4s. Whether
you'll have a round, straight wheel with safe spoke tension is another
issue. Might be time for a new rim, especially since the one you bent
is so lightweight.

-Vee

search to: 'DIY rim repair tool 2' in tech archives

On 15 Jul 2005 09:03:07 -0700, "App" wrote:

After a recent crash I have discovered a permanent bend in my front
rim, more of a single wave that extends about 1/4 of the way around the
rim. Laying the rim on the floor after disassembling the wheel, the
max out of true is ~1/4". There doesn't seem to be a kink in it,but
rather a smooth wave.

Would you beat on the rim with a rubber mallet or just bring it into
true with the spokes?

Oh, yeah, rim is Open Pro 36 spoke.

There is little to be lost by trying to straighten it, but much to be
gained by doing so carefully and well. It's all a matter of value,
though; is an hour or two of your time spent in trying to get it
flattened worth more than the cost of the replacement rim? If the
answer is "yes", then just buy a new rim and either discard the bent
one or hang on to it for one of those odd moments when you really have
nothing else to do.

--
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"App" writes:

After a recent crash I have discovered a permanent bend in my front
rim, more of a single wave that extends about 1/4 of the way around the
rim. Laying the rim on the floor after disassembling the wheel, the
max out of true is ~1/4". There doesn't seem to be a kink in it,but
rather a smooth wave.

If the rim isn't flat - if it rises 1/4" above the table on one side -
then that's not really a problem. An Open Pro aluminum rim 1/4" out of
true can easily be pulled straight by the spokes (especially if its a
32 or 36 spoke wheel), because it's a light aluminum rim and the
spokes control the rim (the same cannot be said for a heavy rim or a
steel rim.)

I think that many rims start out their life (before truing) with this
much bend in them. It could be that your rim came from the factory
with this problem.

If the rim has a problem on one side and not another, then i'd be much
more concerned, that is quite unusual, and I would probably purchase
another rim.

- Don Gillies
San Diego, CA

App wrote:

After a recent crash I have discovered a permanent bend in my front
rim, more of a single wave that extends about 1/4 of the way around the
rim. Laying the rim on the floor after disassembling the wheel, the
max out of true is ~1/4". There doesn't seem to be a kink in it,but
rather a smooth wave.

Would you beat on the rim with a rubber mallet or just bring it into
true with the spokes?

Oh, yeah, rim is Open Pro 36 spoke.

Given the amount of hassle involved in trying to get it straight, I'd
buy a new rim - especially as this is a current production model so you
can get a match.

I had a slightly bent Open 4CD which built into a wheel which was
straight, but predictably had uneven spoke tension. I saved the spokes
and put a cheap MA3 on there instead (MA3 and Open 4CD are virtually the
same ERD), and all is well.

Don wrote:
I think that many rims start out their life (before truing) with this
much bend in them. It could be that your rim came from the factory
with this problem.
If the rim has a problem on one side and not another, then i'd be much
more concerned, that is quite unusual, and I would probably purchase
another rim.

Rim was perfectly true prior to build; crash rendered it bent. What do
you mean "on one side and not another"?

Do you mean that the rim has been compressed laterally (box section is
squished)? 'Cuz that isn't the case. The rim simply is out of true in
a semi-sinusoidal fashion with only one phase. Maybe 1/2 phase?,
anyway, the rest of the rim is true and the "bent" section is out to
one side ~1/4" at it's greatest excursion.

Anyway, based on the info/opinion in the responses, I am going to
rebuild it (coupla bent spokes when I de-tensioned the wheel so I fully
disassembled it and threw out the bent ones) without wanking on it.

I'll post results of that rebuild including spoke tension in that
region by spoke.

Thanks for all your input.

App

The sometimes undeniable Zog wrote:
especially as this is a current production model so you
can get a match.

Sadly, no. It is the RED open pro. Available only as NOS. So I'll
give it a whirl - don't think it'll be too bad - flattening the bent
section by leaning on the rim on the floor took only small amount of
pressure.

I could get a black or silver replacement, but, hey, aesthetics DO
matter.

I am going to try - 1.5 hours to very possibly save myself the effort
of finding another NOS red OP rim. Plus, I just built the damn things.
Worth it, I think.

App

On 15 Jul 2005 09:03:07 -0700, "App" wrote:

After a recent crash I have discovered a permanent bend in my front
rim, more of a single wave that extends about 1/4 of the way around the
rim. Laying the rim on the floor after disassembling the wheel, the
max out of true is ~1/4". There doesn't seem to be a kink in it,but
rather a smooth wave.

Would you beat on the rim with a rubber mallet or just bring it into
true with the spokes?

Oh, yeah, rim is Open Pro 36 spoke.

I recently had a rim that was bent worse than that, courtesy of being
in a cargo trailer with a bunch of other bikes during a serious
accident. For what it's worth it's an Alex DA16, 700c, 36 spoke.

It never occurred to me to try to beat it with a rubber mallet.
Instead I removed the rim from the wheel, first taping the spokes
together at their outer crosses. I laid the rim on a carpeted surface,
concave side down, with the out-of-round spot resting on one leg of my
work stand. I jumped up and down on the two high spots (one foot on
each spot), then checked for flatness on my coffee table.

A few iterations of the above and the rim was pretty flat again. I
relaced it, tensioned and trued, and am still using that wheel. In
fact I'm planning on climbing Going-to-the-Sun Road in Glacier
National Park on that bike next week. ;-)


jeverett3ATearthlinkDOTnet http://home.earthlink.net/~jeverett3

App Wrote:
The sometimes undeniable Zog wrote:
especially as this is a current production model so you
can get a match.

Sadly, no. It is the RED open pro. Available only as NOS. So I'll
give it a whirl - don't think it'll be too bad - flattening the bent
section by leaning on the rim on the floor took only small amount of
pressure.

I could get a black or silver replacement, but, hey, aesthetics DO
matter.

I am going to try - 1.5 hours to very possibly save myself the effort
of finding another NOS red OP rim. Plus, I just built the dam
things.
Worth it, I think.

App

I broke a mallet trying this once, the steel Schwinn rim barel
returned back toward round so I gave up and bought another wheel.

I still have the wheel, and it could still be ridden at slow speed, bu
even if straightened would leave me wondering about the strength of th
wheel if I was at speed

--
meb