bent chain ring

Standard described technique is to grip it with a crescent wrench and
carefully bend back into shape; no heating required. Replacement
chainrings are also readily available at your LBS and many places
online.

Lou D'Amelio

Yarper said:

Hi all,

I have an old bike whose largest of 3 chain rings is bent inward.
My plan was to just not use chain rings #2 and #3, but
if I wanted to, what are your opinions on how to best
unbend it? It's pretty thick metal. Maybe heat it first?

Thanks.

I don't know anything particular to bicycle parts, but-

If it is steel, heating it to any useful temperature (red-orange!) would
likely destroy any finish it has. If the finish isn't important, then
torch-heating it is the best way. Otherwise, you can just clamp it in a
vise (between some pieces of wood) and bend it until it's "straight
enough", and it will /probably/ still be strong enough to use.
.......
If it's aluminum, toss it in the trash/recycling bin (or--if it's a
vintage part, use it for display purposes only). Aluminum develops
fatigue cracks badly when bent cold, and cannot be safely bent back into
its original shape even if heat is applied.
~

Yarper said:

Hi all,

I have an old bike whose largest of 3 chain rings is bent inward.
My plan was to just not use chain rings #2 and #3, but
if I wanted to, what are your opinions on how to best
unbend it? It's pretty thick metal. Maybe heat it first?

Thanks.

S. Brown has a webpage about this at:
<http://www.sheldonbrown.com/straighten-chw.html>.

--
Tom Sherman - Post Free or Die!

"DougC" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Yarper said:

Hi all,

I have an old bike whose largest of 3 chain rings is bent inward.
My plan was to just not use chain rings #2 and #3, but
if I wanted to, what are your opinions on how to best
unbend it? It's pretty thick metal. Maybe heat it first?

Thanks.

I don't know anything particular to bicycle parts, but-

If it is steel, heating it to any useful temperature (red-orange!) would
likely destroy any finish it has. If the finish isn't important, then
torch-heating it is the best way. Otherwise, you can just clamp it in a
vise (between some pieces of wood) and bend it until it's "straight
enough", and it will /probably/ still be strong enough to use.
......
If it's aluminum, toss it in the trash/recycling bin (or--if it's a
vintage part, use it for display purposes only). Aluminum develops fatigue
cracks badly when bent cold, and cannot be safely bent back into its
original shape even if heat is applied.
~

IMO, I'd bend it back and ride it. Half the circumference of the chainring
is engaged...

Then again I ride a cracked-chainstay MTB frame with appropriate inspection
intervals.

--
Phil

Lou D'Amelio said:

Standard described technique is to grip it with a crescent wrench and
carefully bend back into shape; no heating required. Replacement
chainrings are also readily available at your LBS and many places
online.

Lou D'Amelio

Like he said. This is no big deal.

Ron

Lou D'Amelio said:

Standard described technique is to grip it with a crescent wrench and
carefully bend back into shape; no heating required. Replacement
chainrings are also readily available at your LBS and many places
online.

That worked, thanks.