I think my freehub has failed yet again, this is the 3rd time and each time it has failed in almost exactly the same situation.
Going in to a small dip followed by a steep incline with tree roots, suspension compresses in the dip and I give it a bit of effort then "crunch". It feels like the gears aren't indexed right for a split second but it feels stiff and made some awful sounds on the way back to the car.
Haven't taken the freehub apart yet but the last 2 times the pawl has been pushed back into the bearing and as a result its destroyed the bearing, freehub etc.
Am I doing something wrong? It's not an ebike and I'm definitely not a powerfully built hill climb monster, I had already selected my gear leading up to the dip so I definitely wasn't mid-shift when putting the effort in.
I noticed the manufacturer has changed the free hub from 6 to 4 pawls which makes me think there may be an existing fault with my model of freehub?
What brand?
Ah yes that might help! Sonder Alpha 29 rear wheel with micro spline freehub.
I had already selected my gear leading up to the dip
Was that 1st gear? Is your chain a bit short and going massively tight under the as the suspension compresses?
Yes it would have been first gear.
I've kept the chain length exactly the same since it was set up by the shop, it doesn't look too tight but maybe that's something to look in to.
I'd been on some rough tree roots earlier in the ride, I could hear the chain rattling as I bounced over the roots so I didn't think it was too loose.
I'm not exactly sure what you mean by "pawl pushed back into the bearing". Do you mean getting stuck inside its pocket and failing to pop back?
If so, it could just be that they've been greased, and the grease is thick enough to stop them returning?
I don't know what make of hub that is - Sonder are probably buying them in from someone (I don't know who) but it's probably a perfectly respectable brand.
I would try returning them to the seller and let them figure it out, but if that's not possible, clean them up, inspect the pawls for damage, check the springs are happy, lubricate - they're pretty simple things at the end of the day.
If none of that works, you could in theory replace the hub (easier than it sounds but a bit time-consuming) or buy a new wheel. Depends on whether you have more time or more money!
Out of the 6 pawls one of them has actually been pushed through the freehub and destroyed the inner bearing/freehub (towards the spindle/thru axle).
Maybe the pawl has failed to bounce back up quick enough (maybe due to the grease?) just as I started to put some effort through the drivetrain? The pawl has got now where to go so the bottom of the pawl/freehub is the weakest point and it gives way?
I can't post a picture unfortunately but if you can imagine a car alloy wheel hitting a pot hole and cracking you sort of on the right track!
I would be looking to replace it. But with one made from metal rather than cheese.
I've kept the chain length exactly the same since it was set up by the shop,
I wouldn't rule it out just because the shop assembled it/did the PDI!
Let all the air out of the shock, put it in first gear and compress suspension right down. You should still have a little bit of slack in the derailleur arm.
If you've 6 pawls and only 1 broken, it should (probably) still work OK. I'd remove the broken bits, dress the damage (or replace the bearing if FUBAR'd), sort the pawl lube viscosity and chain length then see how it is. Our tandem hub has just 3 pawls and on inspection, we'd ground 2 to dust plus one of the 2 freehub bearings - without even noticing it. There's a bit more torque going through a loaded tandem transmission so 1 pawl did pretty well. Caveat, my pawls and hubs are decent Hope's and not Sonder's no doubt Chinese cheesium so that may (or may not) make a difference.
Alternatively, get Alpkit to fix it under their world beating guarantee...
<edit> Oh, and can you post a pic so we can all see what we're speculating about...
If it's failed 3 times, I'd be finding a new wheel/hub from a more reliable brand. Stuff breaks but thats too often to be more than just 'bad luck'. Need to be able to trust the bits on your bike are reliable...lifes too short for ruined rides with the same damn mechanical
If you go for a Hope hub, they offer a set of "Heavy Duty Pawl Spring" for trails/DH use [ HUB561 ]. You might as well fit them from new.
The Alpkit Alpha free hubs seem to be a bit weak/ problematic- when researching my Broken Road purchase it came up as a weakness in a few search results/reviews.
