What has happened to my spokes?

[winjim]

Just before Xmas I swapped my cassette over. It wasn't quite shifting right so today I took it off and put it back on again to make sure everything was aligned properly. While it was off I noticed big gouges on all the outer spokes on the drive side, behind where the cassette goes. What could be causing this? They look fresh. Surely it can't be the cassette as that sits a couple of mm out from the spokes, and anyway these gouges are within the radius of the largest sprocket, if you see what I mean.

What's caused it, should I be worried and am I going to need my rear wheel rebuilding?

 

[RebornBumbler]

Hard to be sure, but it looks like only minor scraping to the black finish - perhaps you got a bit of wire caught round there at some point ?

 

[cyberknight]

Do you use the lowest gear ?
Im guessing something to do with the low stop but the rear derailleur would catch it higher up the spoke so is the chain catching the spokes ?

 

[winjim]

It doesn't photograph too well but it's not just scraping on the black finish - there's definitely jagged metal.

 

[cyberknight]

It doesn't photograph too well but it's not just scraping on the black finish - there's definitely jagged metal.

Definite chunk out of at least one i would respoke the jagged ones at the least imho.

 

[winjim]

Do you use the lowest gear ?
Im guessing something to do with the low stop but the rear derailleur would catch it higher up the spoke so is the chain catching the spokes ?

I did consider that, but then the chain would need to be between the sprocket and the spokes.

 

[HarryTheDog]

Has your chain has come of at some time jamming between the cassette and wheel and you carried on pedaling?. Mine kept coming off during a MTB enduro and by the end of it I had nearly cut through the spokes.

 

[wam68]

The only time I ever saw anything like that was when the chain came of the low gear ( big cog ) and ripped pieces out of my spokes. Very similar to your pic. Other than that I have no idea. Sorry

 

[winjim]

I don't think the chain could have come off, damaged the spokes in that way, and then come back on although there has been some odd clunky shifting on the large sprocket. The damage goes right down to the level of the hub flange, and that's a 30 tooth sprocket. This photo is with the cassette installed:

Maybe I should've left the pie plate on.

 

[shouldbeinbed]

Flexy spokes, maybe an unnoticed manufacturing ding or burr on the back of the old cassette.

 

[winjim]

Old cassette had pie plate in place so it's happened since the swap. Working assumption has to be chain jumping off and on again I think, although I'm still skeptical...

I've been meaning to get into wheelbuilding so I guess I'll start by having a go at respoking this one.

 

[raleighnut]

Old cassette had pie plate in place so it's happened since the swap. Working assumption has to be chain jumping off and on again I think, although I'm still skeptical...

I've been meaning to get into wheelbuilding so I guess I'll start by having a go at respoking this one.

Its easier to do them one at a time and then you can avoid needing to retrue the whole wheel, just get each one right before going on to the next.

 

[Flying Dodo]

I'd agree that the damage would have been done by the chain coming off - I've seen exactly that sort of scrapping on the spokes on one of our bikes, and ended up replacing 4 spokes.

 

[Yellow Saddle]

Your chain did it, no doubt about that. However, that's not too serious, no need to replace those spokes. Just file off the jagged bits and check your limit setting on the derailler. The low setting is too low.

 

[zaza123]

Are you sure it wasn't done while you removed the old cassette. Just a thought.