Freehub seized
My ride today had to be aborted when the freehub on my Mavic R-SYS SLRs seized up - I could still freewheel, but it was too stiff for the derailleur, so as soon as I stopped pedalling, the chain went slack and threatened to end up in the wheel - it also made starting to pedal again a bit of a lottery. I rode it home treating it like a fixie and cursing every traffic light. Stripped the hub off, reset the pawls, bit of light oil and the hub is fine. No sign of unusual wear inside the freehub body or on the pawls, everything was clean and already lubricated.
Don't want this happening again, even though at a pinch it might be a roadside fix provided you have two 5mm allen keys, as it should be possible to take the freehub off with the cassette attached. Good chance of losing one of the pawls in the grass, though, were one to try, and a lot harder to get the hub body back on with the cassette attached since you have to hold the pawls in while you ease it over them.
So what happened? Could one of the pawls have moved - but if so, why no wear to the freehub body or pawls, since the hub did freewheel - reluctantly - with my momentum to move it (you could turn it by hand, too, but only with some effort)? Has anyone else had this happen to them?
Don't want this happening again, even though at a pinch it might be a roadside fix provided you have two 5mm allen keys, as it should be possible to take the freehub off with the cassette attached. Good chance of losing one of the pawls in the grass, though, were one to try, and a lot harder to get the hub body back on with the cassette attached since you have to hold the pawls in while you ease it over them.
So what happened? Could one of the pawls have moved - but if so, why no wear to the freehub body or pawls, since the hub did freewheel - reluctantly - with my momentum to move it (you could turn it by hand, too, but only with some effort)? Has anyone else had this happen to them?
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Comments
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Probably nothing to do with the pawls. Sounds like the freehub bearings are partly seized - did you check them when you checked the rest of it?0
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I'm guessing it was accompanied by a noise like a wookie? Not sure if all Mavics have the same design but typically if crap gets in the freehub it damages the nylon bush. You can get a replacement freehub off CRC or Wiggle if it keeps happening after you're cleaned it all up. I replaced my Ksyrium freehub a few weeks ago and it sorted it until the rim cracked, but that's another story....0
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Chain slap can be caused by the jockey wheels too...left the forum March 20230
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The freehub bearings are fine, the bush is fine, hence my confusion. The freehub was definitely the problem - you could only just turn it by hand - but no wookie noises. It sounded normal when freewheeling, not like an oil-starved or overtight bearing. That's what's so weird. I took the cassette off; checked the freehub - almost locked solid. Undid the axle, pulled the freehub body off easily. One of the pawls pinged out, but they often do that - have I mentioned it's a crap design? Hub was clean inside, bush was undamaged, bearing smooth, washer in place etc. Gave it a wipe, relubed it (machine oil), put some grease on the bush for sealing, reseated the pawls, replaced the freehub body. Refitted the axle. Everything working fine. WTF?
The whole wheelset was new in July and has done less than 500k (a lot of it wet or damp, granted).0 -
Sorted, I think. Checking the Mavic dealer site, it turns out that the freehub design changed. Pre-2013 wheels have an 8mm axle; later wheels have a 9mm axle. Although I bought the wheels in July this year, they are a 2012 set. I bought the freehub at the same time (to change from Campag to Shimano) but it, of course, was a 2014 part. It shipped with a variety of washers, and I originally installed the wrong one (because the one I installed looked like the one I removed). When fitting current model Mavic freehubs to older model wheels, you need to use a top-hat washer that shims the axle to the right diameter. I've now installed this and we'll see. I suspect I'll need to replace the nylon lip seal as this will have worn from the play in the freehub, but this should stop the jamming.
Relevant tech doc here: http://www.tech-mavic.com/tech-mavic/te ... ts/2_4.pdf
(Username mavic-com, password dealer).0 -
Your original symptoms are what you can expect every time the Mavic freehub dries out; just follow the instructions and make sure you use oil in the amount specified and all will be fine. If only all freehubs were as easy to service..0
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In this case lubrication had nothing to do with it. That's what confused me - I strip and service all my bikes regularly, and when I took the FH apart, it was clean and lubed. You'd have thought, given the effect of using the wrong washer, that Mavic might ship the relevant document with the freehub...crikey wrote:Your original symptoms are what you can expect every time the Mavic freehub dries out; just follow the instructions and make sure you use oil in the amount specified and all will be fine. If only all freehubs were as easy to service..0
