Have you ever straightened a bent cassette cog?

[Louis]

I'm wondering if there is any hope of rescuing the cassette, given how expensive the 12-34s seem to be these days.

While transferring my well-used but still perfectly serviceable 12-34 cassette from one wheel to another I buggered up a two or three tooth section on the 26 cog. (that is one of the cogs that is riveted to the carrier.) Some gorilla (aka me) did not use a torque wrench when this cassette was last installed and it took me about 30 minutes of effort with my chain whip and breaker bar to loosen the lock ring. At some point, while attempting to hold the chain whip with my left hand, I must have allowed it to twist, which bent the teeth on the cog. (next time I won't try to do this alone - another pair of hands will help)

I don't think I'll be able to get a needle-nose plier in there to grab the cog, but since the teeth are bent "out" I might be able to use a punch and bash them back in a bit. I rode that wheel today and it shifts across the entire range fine, but makes a noise in the 26 and a very small noise in the 23. I could try to live with it, especially since I don't use the 26 often, but I'd like to try to fix it if others have had success doing this. Obviously it would be a lot easier if this were one of the free cogs, but unfortunately it isn't.

For reference the cassette is 12,14,16,18,20,23,26,30,34.

Also, if you happen to have a 12-34 you'd like to sell, do send me a PM.

Thanks

[buldogge]

Louis...Why can't you take the individual cog and lay it on a hard/flat surface to reshape it with...say...a hammer.

???

-Mark in St. Louis

[bike22]

Louis...Why can't you take the individual cog and lay it on a hard/flat surface to reshape it with...say...a hammer.

???

-Mark in St. Louis
...
(that is one of the cogs that is riveted to the carrier.)

[Dekonick]

try using a wrench perhaps? Somehow if it is not a loose ring, I doubt you will have success. Not sure you can get much of a tool in the space, and obviously you cant take it out to deal with it in a normal fashion. Good luck and follow up with your success (or failure)
:hello:

[gdw]

I loaned a bike to a team member for the 24 Hour of Moab a few years ago and he managed to bend a cog and chainring during the race. I used a large flat head screwdriver to bend it back into roughly its original shape. Shove the screwdriver between the bent cog and the cog next to it and twist the screwdriver gently to bend the damaged cog/teeth back into shape.

[xjoex]

You can bend it back, but it might always click/tick/ make noise in that gear. In the past I did it with a headset wrench.

But as an aside, has anyone tried the Pedro's vise whip? I picked one up, it is so much nicer than a chain whip.
http://robonza.blogspot.com/2011/05/cool-tool-pedros-vise-whip.html

-Joe

[RPS]

I don't think I'll be able to get a needle-nose plier in there to grab the cog, but since the teeth are bent "out" I might be able to use a punch and bash them back in a bit.
I haven’t tried it and probably wouldn’t for fear of damaging the aluminum carrier, but if I was to try it I’d try to wedge a thin flat plate between cogs as far in as the carrier allows for extra support before trying to tap the teeth straight.

[that guy]

I just did it on a non-seperable, cheapo mtn bike cassette. The combination of whacking it with a hammer and punch and gently squeezing it in the vice got it looking almost straight. YMMV.

[vqdriver]

if the choice is to bend it back or replace it, i'd just whack it back and take my chances.

[DfCas]

If the cog is steel you may have a chance of straightening it and it staying straight. I would use a hammer on a nut driver and tap it back gently until it is straight.

In the mid 90's I folded a cassette cog on an XTR cassette while riding. The cassette was some lightweight alloy, I think. I straightened it back using a nutdriver,but the cog bent again shortly thereafter. I think the alloy was weakened from the initial bend.

Since that time I've only bought steel cassettes