Saw an interesting failure this weekend

[benb]

Saturday morning I came across a stopped rider who was totally hosed and having to wait for his wife to come pick him up. This was in the middle of a 100k ride so he probably had to wait quite a while.

He had a Dura Ace hubs.. the freewheel had completely grenaded internally so that he couldn't pedal because the freewheel spun freely in both directions, making lots of noise.

Anyone ever see this before? What causes that?

[Dave B]

I would imagine the pawls in the hub or what the pawls hook onto broke/shattered. Could have been a worn out part versus just one that failed all of a sudden.

[Black Dog]

http://forums.thepaceline.net/showthread.php?t=185195

[bicycletricycle]

what generation DA hubs?

[benb]

I don't know.. relatively recent as they were dark colored IIRC. I can't recognize DA that well.

[benb]

I don't know.. relatively recent as they were dark colored IIRC. I can't recognize DA that well. I saw DA logos on other components on the bike and the rider said they were Shimano hubs so I assume they were DA as the finish matched the rest of the components.

[rccardr]

Yep, happens. Never seen it with a feehub, but definitely on old and unmaintained/lubed frewheels. Pawls give out and then things go all wobbly. Had it happen to a rider on the fall L'Hombra (anti-Eroica vintage in NJ) last year at about mile 85. We had him shift into the middle cog to minimize the wobbling (and further pawl destruction) and only shift front chainrings on hills. He made it back, but barely.

[Mark McM]

Sure, I've seen a number of freehubs that stopped ratcheting (spun in both directions). Typical causes are: Broken pawls; broken pawl springs; oil/grease that got to thick to allow pawls to engage.

[unterhausen]

I had an ultegra freehub body crack in half once. Rode it on a 400km 600km, a number of 200km and PBP. Drove me nuts until I gave up and set the wheel aside. Finally figured it out a couple of years later. I'm not sure that will lead to freewheeling both ways, mostly it acted a lot like a wheel that flexed too much. I always thought that it should have stranded me, I'm not really sure how it held together being cracked in half like that. I must be weaker than I though. I knew a couple of people that ended up buying a wheel during PBP, pretty strange given the small number of people I know that rode it.