Rear hub damage

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Rear hub damage

Postby Rex » Sun Apr 07, 2013 2:06 pm

So I needed to replace my cassette today.

Discovered my most used sprockets have damaged the hub, to the point where they move considerably.
I expect my shifting to become even sloppier now.

Any idea what has caused this?

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by BNA » Sun Apr 07, 2013 2:07 pm

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Re: Rear hub damage

Postby jasonc » Sun Apr 07, 2013 2:07 pm

cassette not torqued on correctly/enough
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Re: Rear hub damage

Postby il padrone » Sun Apr 07, 2013 3:25 pm

Nup, weight-weeny's alloy freehub.

Solution is to get a new freehub body, and if possible get a steel body.
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Re: Rear hub damage

Postby warthog1 » Sun Apr 07, 2013 4:04 pm

Probably a combination of both of the above.
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Re: Rear hub damage

Postby Baalzamon » Sun Apr 07, 2013 4:47 pm

Incorrect torque is my vote
One time I had to remove my cassette and use a pipe.... on a socket wrench. Normally I don't have to do this. Now my bike had been at a LBS for a service this was before I did it myself. End result was damage as shown in the picture above.
After changing my cassette I torqued it back up correctly to 40nm. I changed wheelsets a few weeks back and removed the cassette. No further damage to the freehub had been noted.
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Re: Rear hub damage

Postby Rex » Sun Apr 07, 2013 6:06 pm

Cheers for the replies guys.

I actually think it's both.
Earlier last week I took a close look at the previous cassette (before making my decision it needed to be replaced) and noticed it was VERY loose on the hub, like no tension.
Secondly, I haven't looked at any 'top-end' hubs but I can't believe they would be made of an alloy that soft.

Lesson learnt... time to buy a torque wrench
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Re: Rear hub damage

Postby AndrewBurns » Sun Apr 07, 2013 6:32 pm

Also blame Shimano's insufficent spline depth, Campy freehubs have much deeper splines which means less concentrated stress and less of that kind of damage.
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Re: Rear hub damage

Postby il padrone » Sun Apr 07, 2013 8:07 pm

Rex wrote:Secondly, I haven't looked at any 'top-end' hubs but I can't believe they would be made of an alloy that soft.

They are!! Beware.

Re. torquing up your 11t - beware of this also.

I don't know about yours and whether road lockrings are somehow different, but the Shimano lockrings I have always used have teeth that notch into the cassette. They give a significant clicking engagement as you tighten them. Tighten them too much and it is possible to make them extremely difficult to remove. Once they start to really tighten up with a clicking ratchet noise you really only need to push them 4-5 clicks further.

I ride MTBs with very low gears and use them to haul loaded touring bikes up 15%+ climbs = much greater torque on the freehub than any road bike. I never tighten the lockring more than about 4 clicks, so it is quite easy to remove. I have never encountered damage like you show, but then my freehubs are steel.
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Re: Rear hub damage

Postby biker jk » Mon Apr 08, 2013 10:09 am

AndrewBurns wrote:Also blame Shimano's insufficent spline depth, Campy freehubs have much deeper splines which means less concentrated stress and less of that kind of damage.


Shimano freehubs are made of steel (except Dura Ace which is titanium) not aluminium alloy. I have never had a problem like the OP with Shimano freehubs.
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Re: Rear hub damage

Postby il padrone » Mon Apr 08, 2013 12:21 pm

Read what Sheldon Brown has to say about this. His photo of a non-Shimano freehub looks just like yours :wink:

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Re: Rear hub damage

Postby jacks1071 » Mon Apr 08, 2013 1:14 pm

Rex wrote:Cheers for the replies guys.

I actually think it's both.
Earlier last week I took a close look at the previous cassette (before making my decision it needed to be replaced) and noticed it was VERY loose on the hub, like no tension.
Secondly, I haven't looked at any 'top-end' hubs but I can't believe they would be made of an alloy that soft.

Lesson learnt... time to buy a torque wrench


Its a long way from requiring a replacement, if the bearings inside the freehub are still good keep running it.

Torque the lockring to 40Nm when you re-install the cassette and that'll minimise of not stop any further damage.

Damage on alloy freehubs is a non-issue if the lockring is installed properly.
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Re: Rear hub damage

Postby Rex » Mon Apr 08, 2013 2:42 pm

I have a spare Shimano wheel and the hub body is fine on it.
Am I able to just swap it?
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Re: Rear hub damage

Postby Pottsy » Mon Apr 08, 2013 9:09 pm

Rex wrote:I have a spare Shimano wheel and the hub body is fine on it.
Am I able to just swap it?


If the hub is the same then go for it.

But there is no need to, just file off any lumps of metal, grease the splines & tighten it up.
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Re: Rear hub damage

Postby ZepinAtor » Mon Apr 08, 2013 9:41 pm

If free hub body gouging is an issue you can install these AC "cassette clips" (or other aftermarket options) which have been used by some mates of mine with similar issues on their Cycleops power hubs.

http://www.amclassic.com/documents/help ... ltegra.pdf
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Re: Rear hub damage

Postby MichaelB » Tue Apr 09, 2013 10:53 am

ZepinAtor wrote:If free hub body gouging is an issue you can install these AC "cassette clips" (or other aftermarket options) which have been used by some mates of mine with similar issues on their Cycleops power hubs.

http://www.amclassic.com/documents/help ... ltegra.pdf



I'm with warthog1 on this - a combination of both (and no, I don't have a 40Nm torque wrench, and most probably don't).

I just fitted these AM clips on the weekend on my CM hubs on the Volagi - easy as and will keep an eye on it to see how they work.

BTW, the kit I got had the clips for the DA, Ultegra and pins for the 105 setup as well. The DA & Ultegra clips are slightly different in height due to the additional pairing of cogs on the DA cassettes.
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Re: Rear hub damage

Postby __PG__ » Fri Apr 19, 2013 9:24 am

The other day I changed cassettes on my Alchemy ORC hubs. This wasn't a straight-forward procedure, but with a some tapping of the cassette against the engagement direction, and some further taps from behind, I managed to remove it.

The cassette had left some marks on the freehub. The cassette (Shimano 8-speed HG50) was tightened to the correct torque specification. I've replaced it with a SRAM 10-speed PG1070 cassette.

I asked Alchemy about the scouring, and any rules of thumbs for maintaining alloy freehub bodies. This was their reply. It contains some very important information
Alchemy wrote:Thanks for contacting me. I'm glad that you like the hubs. Unfortunately, Shimano 10sp cogs are especially hard on all alloy cassette bodies. The reason is that the cogs are thin and Shimano removed 1/3 of the splines on most of the "loose" cogs which exacerbates the problem.

Sram 10sp cassettes are definitely easier on alloy bodies than Shimano cassettes, especially the "red" version. However, the PG-1070 is still much better than the Shimano cogs (if you look closely, you'll notice that all of the cogs have a full complement of 9 splines, and the fit is better).

As for damage, it is unlikely that the "gouging" will cause you any problems. I like to knock the burrs off with a file when I install the new cassette. It is not necessary to put grease on the cassette body itself (although it doesn't hurt other than attracting dirt), but you must put grease on the threads and a little on the underside of the flange of the lock-ring. Many people fail to do this but it is very important. A torque wrench just measures the force you put into the handle and "clicks" when you reach the pre-set value. It does not measure the "clamping pressure" of the threaded assembly. If you install a lockring without any grease, the friction between the mating threads and the flange to cog contact will create a "false" torque reading. In other words, the point of a torque specification is to reach a desired clamping force. But, if the assembly is dry, the torque setting is reached before the assembly is adequately clamped (due to friction).

A very good point, and I admit that I've never greased the threads of my lockring. It's a bit of a blind-side for me, as of course you'd do it for other areas of the bike which require high torque (e.g. pedals, bottom brackets etc).
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Re: Rear hub damage

Postby Rex » Fri Apr 19, 2013 10:40 am

Thanks for that info PG, much appreciated.

So is this case to go SRAM 10spd cassettes over Shimano?
I'll definitely be considering that when I replace it soon.

I too have never greased the lockring, but I haven't used a torque wrench either :/
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Re: Rear hub damage

Postby queequeg » Fri Apr 19, 2013 11:55 pm

Rex wrote:Thanks for that info PG, much appreciated.

So is this case to go SRAM 10spd cassettes over Shimano?
I'll definitely be considering that when I replace it soon.

I too have never greased the lockring, but I haven't used a torque wrench either :/


The real solution is to get a steel freehub. Alloy freehubs are designed for alloy carriers on the cassette. Even the SRAM road cassettes have loose sprockets, and these will gouge an alloy freehub. I have pictures to prove it!
All Shimano freehubs are made of steel, except dura-ace ones that are made of titanium instead.
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Re: Rear hub damage

Postby Rex » Sat Apr 20, 2013 1:51 pm

Yes, but I'm certainly not going to limit my future wheel purchase to Shimano only.
Might have to look into the ability to swap a shimano steel hub body to my next wheel purchase brand of choice. Not particularly looking forward to that.
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Re: Rear hub damage

Postby trailgumby » Sat Apr 20, 2013 2:10 pm

I have the same issues on a Sun Dirty Flea hub. It came with a cheap (X-9?) Cassette fitted. I am unimpressed. Underengineered cheap alloy freehub is the root cause, combined with poor cassette design. So much for (then) my nice new bike. :(

My Mavic hubs all have steel freehub bodies - wear not an issue, even on the top end CrossMax SLR.

The Dirty Flea wheel is now on the son's bike and is fitted with an SLX cassette with alloy spiders to prevent a recurrence.
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Re: Rear hub damage

Postby jules21 » Sat Apr 20, 2013 6:50 pm

unless you remove the cassette pins, it's usually only the outboard cogs which are loose. these do not transmit as much torque, due to their ratio. you can see from the pics in this thread that the freehub spline damage is from the middle cogs, which trasmit more torque than the outboard ones and tend to get the most use. i wouldn't worry about the loose, outboard cogs.

you also don't need a torque wrench to tighten the cassette lockring. just give it a bit of a squeeze, but don't put your bodyweight into it. a common reason for lockrings coming loose is erroneous installation of cogs or spacers.
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Re: Rear hub damage

Postby queequeg » Sat Apr 20, 2013 11:42 pm

Rex wrote:Yes, but I'm certainly not going to limit my future wheel purchase to Shimano only.
Might have to look into the ability to swap a shimano steel hub body to my next wheel purchase brand of choice. Not particularly looking forward to that.


You don't need to limit yourself to Shimano hubs. I bought some hope pro 2 hubs, and bought a steel freehub to replace the fitted alloy one.
My point was that Shimano does not sell hubs with alloy freehubs, so you don't have this issue.
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