[Gendy]

The rear hub on my Farley started slipping on my last ride. It may have been after trying to get up a steep rock section, and exerting a lot of force on the pedal. I pulled the freehub off, and everything looked pretty good to me. I didnt see any cracks in the hub shell, or the ring with the grooves in it where the pawls engage. Only thing i did notice was two strands of metal, about the size of a thick hair, that seemed to have been sheered off. I cant tell how that would have happened. Anybody have any ideas? I thought maybe the gear ring was spinning within the hub body, but i wasn't able to spin it by hand with little leverage.

 

[HuckingKiwi]

The rear hub on my Farley started slipping on my last ride. It may have been after trying to get up a steep rock section, and exerting a lot of force on the pedal. I pulled the freehub off, and everything looked pretty good to me. I didnt see any cracks in the hub shell, or the ring with the grooves in it where the pawls engage. Only thing i did notice was two strands of metal, about the size of a thick hair, that seemed to have been sheered off. I cant tell how that would have happened. Anybody have any ideas? I thought maybe the gear ring was spinning within the hub body, but i wasn't able to spin it by hand with little leverage.

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When the hub "slipped" did it make a loud noise similar to a skipping chain or was it silent?

 

[Gendy]

I honestly can't remember at this point, as it was about a month ago. I was able to limp it out on flat sections in high gear with very light pedal pressure. Seems like the hub is toast, but i'm just curious what actually failed. Even if it cant be determined from my shoddy photos, i'd be interested to hear a common failure cause.

 

[kevin_sbay]

I honestly can't remember at this point, as it was about a month ago. I was able to limp it out on flat sections in high gear with very light pedal pressure. Seems like the hub is toast, but i'm just curious what actually failed. Even if it cant be determined from my shoddy photos, i'd be interested to hear a common failure cause.

Interesting. Curious too. Bumping!

 

[mlx john]

It is the inner ring. It's a notorious defect with the bontrager hubs. Ask me how I know... Happened to me in the middle of Mag 7 in Moab.

The inner ratchet ring is bonded, where as (for example) DT Swiss 350/240 threads theirs into the hub. My current Bontrager carbon rim is now laced to a 350.

I was also a mechanic at a Trek dealer, saw this often.

 

[Gendy]

It is the inner ring. It's a notorious defect with the bontrager hubs. Ask me how I know... Happened to me in the middle of Mag 7 in Moab.

The inner ratchet ring is bonded, where as (for example) DT Swiss 350/240 threads theirs into the hub. My current Bontrager carbon rim is now laced to a 350.

I was also a mechanic at a Trek dealer, saw this often.

So is it that i likely broke the bond between the inner ring and the hub? That was my hypothesis, but i dont really know too much about hubs and common failures. Too bad either way, as it seemed like a decent hub, but i wouldn't trust getting another. Interesting about the DT Swiss hubs, i might see if i can try to find a video on how they are made...

Edit: was able to confirm the ratchet ring is slipping

 

[blinkmilkman]

I have multiple Bontrager rapid drive hubs, with one that slipped similar to what you describe. The teeth inside the hub got very slightly dulled and eventually slipped. Once they lose their sharpness, the driver/cassette/chain/crank turning force just slowly slips.

This can happen if the driver isn't engaged properly with the hub and you grind the engagement mechanism (pawls). This is possibly the worst sound in the world 🙁