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Mavic rear wheel binding

3K views 11 replies 7 participants last post by  WBC 
#1 ·
I just recieved a "new to me" set of Mavic cosmos for my cross bike. When I put them in the frame for the first time without a chain. I spun the wheel and it spun for a long time in free wheel mode forward. When I went the opposite direction (backwards) it would only go for half a turn before stopping. When I installed the chain with the new wheels it had sever binding when trying to turn the cranks forward in the work stand. I thought it might be the BB so I tossed in my Mavic K's and it worked fine. I then tried to back pedal the cranks and the chain went slack on the top side of the chainstay. It is something in the rear freehub I think, but don't know what it could be. The only other thing I could think of would be the rear bearings, but the wheel spins so smooth going forward I doubt that it is the bearings. The wheels are 2003 cosmos that have 15 miles on them from a demo bike.
 
#2 ·
I went to the Mavic site and used the tech log in posted here in the past. It looks like the freehub is one assembly. Has anyone ever tried to take one apart? I didn't have a 12mm wrench handy to remove it, but it can't be held together with much more than a retaining clip. Maybe just have a peek to see what is going on inside. From doing some web searching, looks like the older Cosmos have a few problems with the freehubs. Maybe better order one from the LBS just in case.
 
#3 ·
usually when the chain goes slack while backpedalling it's cause the derailleur isn't adjusted perfectly. try a few forward cranks to make sure you're on the right cog before the backpedalling.

sorry for suggesting the obvious if you've allready checked the derailleur allignment.
 
#4 ·
Confused

spookyload said:
without a chain. I spun the wheel and it spun for a long time in free wheel mode forward. When I went the opposite direction (backwards) it would only go for half a turn before stopping.
This is not clear to me. If there is no chain present, then the freehub is not engaged in either direction - the cogs would turn "in the air" in both directions. What you describe says that the hub bearing/seal friction is different in one rotational direction than the other. I've never had this experience, and could only guess that somehow the seal is getting caught when the hub turns in the "backward" direction. The "severe binding" you describe sounds more like brake pad rubbing - turning the crank (forward direction) would not put any singificant stress on the freehub and should be just like spinning the hub with no chain in place. The chain going slack with backpedalling should only happen if the back wheel is somehow anchored - if you have high friction in the freehub body, you normally find the wheel turning backwards (rather than the freewheel mechanism).

I would suggest that you should be able to feel all of this stuff by taking the wheel out of the frame and playing with the hub axle and freehub with your fingers. If all that you describe is happening, then the hub is screwed up in some weird way. It could be that seal, which you should be able to inspect. If the seal was dragging like that in one direction, you'd think it would be a bit chewed up.
 
#6 ·
I disassembled the wheel this morning and found a washer that was in the wrong place on the freewheels side. It was next to the outboard nut and was supposed to be next to the bearing with a dust cap outboard of it. I switched it but didn't have time to put a cassette back on. I am holding my breath and hoping!
 
#8 ·
Fixed the problem. When I took the wheel apart last night, I compared its assembly to what the Diagram at the mavic-tech site showed (thanks for the link C-40). It was assembled wrong. One washer was on the wrong side of a part and it was causing the binding when a cassette was installed. The lockring actually pressed down on the dust cap and caused the bearing to bind. That is why it didn't do it when the wheel wasn't in the bike and no cassette installed. The thing that worries me here is did the 15 demo miles they were ridden damage the drive side bearings because of this? They still feel smooth and there is no binding. We will see.
 
#10 ·
spookyload said:
I just recieved a "new to me" set of Mavic cosmos for my cross bike. When I put them in the frame for the first time without a chain. I spun the wheel and it spun for a long time in free wheel mode forward. When I went the opposite direction (backwards) it would only go for half a turn before stopping. When I installed the chain with the new wheels it had sever binding when trying to turn the cranks forward in the work stand. I thought it might be the BB so I tossed in my Mavic K's and it worked fine. I then tried to back pedal the cranks and the chain went slack on the top side of the chainstay. It is something in the rear freehub I think, but don't know what it could be. The only other thing I could think of would be the rear bearings, but the wheel spins so smooth going forward I doubt that it is the bearings. The wheels are 2003 cosmos that have 15 miles on them from a demo bike.
Are you using the cassette spacer? You may have found the problem with yours, but others should check that they are using the spacer that goes on before the cassette. The freehub body is made wide enough to use the Mavic Campy-10 compatable cassette and needs this spacer for a Shimano-9. - TF
 
#11 ·
WBC said:
Spookyload,

I'm having the same problems with mine. could you show me that diagram or where I could get it to see if mine are assembled wrong also.

Thanks

WBC
Go here: http://www.tech-mavic.com/
Click on english. The user name is mavic-com and the password is dealer. There will be a bunch of tabs on the left. Select "road". Now select cosmos. When it takes you there, you can select a .pdf called small parts. It shows the front and rear hubs in an exploded disassembeld view. It will give you an idea of the order things should go on.
 
#12 ·
Thanks for the link Spookyload

It looks like mine was assembled OK. I just noticed that if I tightened the nuts it would be to tight. However I see that I'm supposed to back them off a quarter turn or so to compensate for the squeeze for the quick release.

TD. Thanks for pointing that out but I do have that spacer fot the 9 spd.

WBC
 
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