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Hi everyone,

I've noticed when I am doing stuff such as gear indexing (and my bike is up on the stand) that there is a slight wobble or oscillation to the smallest two cogs in the cassette. If you look carefully when the wheel is turning at speed, there just seems to be an ever-so-gentle movement. It is quite soothing to watch, like being rocked in a cradle :).

Full confession: I recently "expanded" my bike service skills by my servicing my wheel hubs. I followed such sources as Leonard Zinn and Park Tool videos very carefully.  I made sure of a little play in the hub between the cone and lock nut that would be taken up by the quick release lever's closing. I also torqued the cassette's lock nut to the recommended 40 Nm.

Before I serviced the hubs, I had never noticed this subtle cassette wobble, which is not to say that it was not there before. The smallest two cogs in my 8-Speed cassette are separate, individual cogs from the other six, which are in a cluster, so perhaps this accounts for slight movement, even with a correctly torqued lock nut? As far as I can tell the axle is straight and the rear wheel is adequately true. The bike rides like a good 'un, and I do not feel remotely unsafe and there are no riding or handling issues.

Is this just what road bikes do, or did I mess something up on the hub service? If so, what remedial action might be necessary?

Cheers

roadbikepilgrim

 

P.S. I posted a very similar topic a day or so ago, but can see absolutely no sign of it. Profound apologies if you replied to that one, but I honestly think it did not save. I cannot see it. I am not deliberately wasting forum members' time by posting twice :).

 

15 comments

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Boatsie [386 posts] 1 month ago
0 likes

I'm no expert.
Mine don't wobble.

Did you assemble cassette? Mine has (memory) 2 triple clusters and 3 individual cogs. Spacers are used between during assembly. I don't know spacing, same spacers get placed onto hub as per the way they were in the box. It shouldn't move is what I believe because that'd wear at hub rather than torque axle.

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hirsute [1046 posts] 1 month ago
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Is the cassette lock ring tight enough?

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maviczap [381 posts] 1 month ago
1 like

On more than one occasion I've not put the last cog on the correct spline of the hub body, and then put the lockring on, leading to a slightly loose cassette and visible wobble. Worse with 11speed cassettes.

So check this first, and also check the freehub is tight on the hub too.Maybe the freehub body bearing is knackered?

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hawkinspeter [3933 posts] 1 month ago
4 likes

It shouldn't wobble at all.

My guess would be either the cassette lockring isn't tight enough (usually around 40Nm torque) or that there's a missing spacer so the lockring isn't quite clamping the cassette in place.

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brooksby [4874 posts] 1 month ago
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No. Next?

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Jimnm [322 posts] 1 month ago
2 likes
hirsute wrote:

Is the cassette lock ring tight enough?

I’d say it isn’t. 

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daturaman [45 posts] 1 month ago
2 likes

Hell no it shouldn't wobble. Either get thee to an LBS or get a chain whip, lock ring tool and adjustable spanner and tighten the living fuck out of your lock ring. If that doesn't fix it, your freehub bearings are probaby knackered.

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roadbikepilgrim [6 posts] 1 month ago
0 likes

Hi all,

Thanks very much for your feedback. I would say that the freehub bearings are unlikely to be the problem, because the bike is only 18 months old. I should probably hear a problem in the bearings when I stop pedalling and let the bike freewheel.

As said in my post, I did torque the locknut of the cassette to 40Nm and I also used a torque wrench. There were no spacers in the cassette. The cassette is a Sun Race 12-25 with eight cogs. The two smallest cogs are separate and the other six are in one cluster.

I shall take the cassette off and check for the spline alignment of the two smallest cogs and then re-tighten the locknut to 45-50Nm (or even as daturaman suggests, "tighten the living f**k" out of it!) and see if that does it.

Thanks and regards,

roadbikepilgrim

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ktache [1994 posts] 1 month ago
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There should be no play in the cassette, you shouldn't be able to move them with your fingers, but on rotating the cassette there could be some movement as not all of the teeth are in line to aid with shifting.

I am impressed you have a torque device that can get up to 40.

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mp31 [27 posts] 1 month ago
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Free hub bearings 

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Rod Marton [129 posts] 1 month ago
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Were it the freehub bearings, the casette should wobble as a unit rather than just two sprockets. I've had this happen and it made no difference to the performance. If it is only the two small sprockets it sounds as if the locknut is cross-threaded. I'm not sure what effect this would have on shifting, but I'm sure it won't help. A loose locknut certainly makes shifting rather vague, this might have the same issue.

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Rakkor [18 posts] 1 month ago
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I also had an issue like this where the nut in the centre of the freehub had unwound slightly meaning that the locknut was hittling up against it - tightening this up allowed me to nip up the cassette locknut properly

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Xena [102 posts] 1 month ago
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.Come on it’s not fucking rocket science if it’s moving “play “  then obviously it’s loose for it to wobble I.e.not tight ,not fitting as it should.   First try a new lock nut  , if that doesn’t work .Put on another cassette  ( go to a bike shop if you have to ‘) and see if it still happens . I bet it stops . If not then your hub is fucked and needs replacement.  Don’t tighten the fuck out of anything , You shouldn’t have to , if something don’t work as it should then it’s broke . Do the above and solve this minor fucking issue without all the drama . 

there you go fucking easily solved .    

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srchar [1535 posts] 1 month ago
6 likes

Preferred you in Warrior Princess if I'm honest.

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longassballs [147 posts] 1 month ago
1 like

As said almost certainly the cassette not being on tight enough.

Had this problem myself with an 8 speed cassette and couldn't believe the problem was quite as simple as the locking not being tight enough as I felt I had put it on pretty well. After rebuilding the freehub & wheel bearings three times, I thought fuck it and "tightened the living fuck out of the locking" - no more wobble.

(there might still be a tiny perceptible wobble but that's down to the tolerance limitation of a relatively cheap 8 speed cassette/freehub)