Freehub Failure

[SlowManiac]

What causes a freehub to fail? Loud crack (both times while applying a heavy load while climbing up some rock steps) and cassette spins freely both ways not engaging with the wheel. Don't think the body cracked - just the pawls or whatever.

I've broken 2 now and I'm no gorrilla on the bike. The only thing I can think of is sometimes I pedal quite choppily when negotiating technical stuff - eg pausing on a pedal stroke then suddenly putting down MAX POWER. (sorry had to caps that).

Do freehubs not like that? Would more POE help?

Do they make better (stronger, more durable) freehubs or do you need a better hub?

 

[rone]

What causes a freehub to fail? Loud crack (both times while applying a heavy load while climbing up some rock steps) and cassette spins freely both ways not engaging with the wheel. Don't think the body cracked - just the pawls or whatever.

I've broken 2 now and I'm no gorrilla on the bike. The only thing I can think of is sometimes I pedal quite choppily when negotiating technical stuff - eg pausing on a pedal stroke then suddenly putting down MAX POWER. (sorry had to caps that).

Do freehubs not like that? Would more POE help?

Do they make better (stronger, more durable) freehubs or do you need a better hub?

What wheelset/hubset is it?

 

[SummitFever]

What hubs? There are quite a few different engagement designs, as well as good and bad implementations of the same design.

 

[ChopSticks]

Would more POE help?

increase in POE has nothing to do with strength..... its more related to hub design

ie Hope hubs have 4 paw;s that engage at anyone given time (24/40POE)
Profile have 6 pawls, with only 2 pawls engaging at one time to give a whopping 204POE's
DT have a different design, but have 16/32 teeth engaging at the same/one given time.

tell us what hubs you have an we might be able to help you....

ie Shimano 142 slx? hubs have had cracking issues.

 

[SlowManiac]

Ah - the first one I broke had fairly inexpensive Shimano hub - Shimano M475 alloy hub

The second was a Bontrager Hub from a Bontrager Rhythm Elite wheel

 

[bikeyoulongtime]

pausing on a pedal stroke then suddenly putting down MAX POWER. (sorry had to caps that).

Do freehubs not like that?

Are you applying MAX POWER smoothly? or do you spin up a part pedal stroke and then feel the freehub catch on in a hurry?

Freehubs generally cope better with the former, worse with the latter.

I'm no physicist or engineer - but here's an analogy: think of it like attempting to undo a massively tight (not seized) bolt. Apply a lot of power smoothly, and you'll get it undone. Apply the same power in a hell of a hurry, you increase the likelihood of fracturing the bolt (or the tool).

Any freehub can fail, some designs are better or worse, and some are better or worse implemented. I can see why lots of pawls engaging at the same time could be possibly stronger - in terms of spreading a force between more components, but I might also be talking shit. Given that I work in a bike shop, that's actually most likely to be true.

 

[SlowManiac]

Are you applying MAX POWER smoothly? or do you spin up a part pedal stroke and then feel the freehub catch on in a hurry?

Freehubs generally cope better with the former, worse with the latter.

I'm no physicist or engineer - but here's an analogy: think of it like attempting to undo a massively tight (not seized) bolt. Apply a lot of power smoothly, and you'll get it undone. Apply the same power in a hell of a hurry, you increase the likelihood of fracturing the bolt (or the tool).

Yeah I was kind of thinking along those lines, I could definitely learn to apply MAX POWER more smoothly.
Since I've broken 2 separate freehubs I was wondering if it could be related to technique.

So what are the most indestructible hubs that are reasonably priced?

 

[SummitFever]

Got any pics of busted Bonty freehub? Pics will help alot in diagnosing the cause of the problem. There are a variety of hubs that fail prematurely because of weak undersized aluminium axles. The axles bend under load, the pawls get out of alignment and things start to come apart. Worn / loose bearings can exacerbate the problem.

 

[SlowManiac]

No pics unfortunately, bike is at the shop.
One thing I noticed is that the hub had gotten quieter and actually was completely silent while free wheeling on the day it broke. I guess that could be a sign something was about to go wrong.

 

[BLKFOZ]

I've had no end of trouble with bonty branded hubs on two different bikes. Rhythm Pro Scandium 26" - after the 6th warranty fix/replacement of the rear hub I bought new TWE wheels cause I was sick of the trouble of going to the shop. Now running pro II evo.
Racelite 29" lasted maybe 1500km - started playing up, back to shop to be "fixed". Next ride the hub was cracked in 5 places and an oval shape - freehub looked like it had been through a mincer. Replacement RXL's with DT240's have been solid.

 

[Wombatone]

Get a Hope hub and be happy ever after