Anyone ever broken a chainring tooth...

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ColinJ

Puzzle game procrastinator!
Are you sure it is broken and not just one of those that are cut down to aid shifting between rings?
 
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OP
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Hawk

Guru
Are you sure it is broken and not just one of those that are cut down to aid shifting between rings?

Good point but doesn't look it... in the first photo, taken from above, you can sorta see that that tooth has warped to the left slightly too, this is noticeable - the top of the tooth sticks out to the left.

I noticed this when my chain kept slipping down a gear when on the middle ring at the front and a low ring at the back...
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machew

Veteran
Bent a tooth buy dropping the cog from workbench, straightened it out with a vice. First ride, the bent tooth fell off
 

GilesM

Legendary Member
Location
East Lothian
Boken plenty of big ring teeth on rocks, but never on a middle ring, that's a bit odd, and tricky to work out how it could happen.
 

Scilly Suffolk

Über Member
I don't know how you might have done this, but would hazard that the apparent lack of maintenance was a contributing factor...
 
OP
OP
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Hawk

Guru
I don't know how you might have done this, but would hazard that the apparent lack of maintenance was a contributing factor...

Was waiting for someone to say that :P

This photo was taken after a dirty 60mile trip and I was in the process of cleaning it up when I took this. (the "oily" splodge is the cleaner I was about to wipe away)

In any case, all the gunk that is present is concentrated well away from the area that the chain actually contacts so I have thought it irrelevant?
 

Scilly Suffolk

Über Member
Fair enough: if you're just back from a mud bath but normally keep it "eat your dinner off clean", then I withdraw my last comment!
 

andrew_s

Legendary Member
Location
Gloucester
The only way you are going to tell if it's a broken tooth or a short tooth to assist shifting is to compare the ring with a new one.
I'd hazard a guess that it's a short tooth, as the "break" looks to be exactly horizontal, and the top surface seems well worn.

I've broken several cassette teeth, once reducing a 17 tooth sprocket to 5 + 2 short teeth (work bike, only one gear ever used).
 
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