Cassette lockring coming loose

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Stradageek
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Joined: 17 Jan 2011, 1:07pm

Cassette lockring coming loose

Post by Stradageek »

It's not a big problem but I do occasionally experience a cassette lockring coming loose.

The cassettes were either SRAM or Shimano 9-speed and the hubs Quando or Vision. I've done all the cassette mounting myself, cleaned the freehubs before installing a new cassette and used a torque wrench to make sure I have at least 40Nm torque on the lockring.

It's the rattle at the back that alerts me to the problem and it doesn't affect the gear changes, it's just a bit annoying and something I wouldn't expect to happen in only a couple of thousand miles.

Is it possible that the plastic sprocket spacers are compressing?

Just interested to know if anyone else has had this problem?

PS the bikes are Speedmachine and Bacchetta recumbents.
cromo
Posts: 89
Joined: 3 Aug 2009, 9:10am

Re: Cassette lockring coming loose

Post by cromo »

I use 9 speed cassettes on my bikes and did have a problem with a SRAM cassette becoming loose. It had been tightened to the correct torque. I assumed it was the spacers compressing. I replaced the SRAM cassette as I was not happy with the ratios so I don't know if applying the correct torque again would have solved the problem from recurring.
I have not had the same problem with Shimano cassettes.
slowster
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Joined: 7 Jul 2017, 10:37am

Re: Cassette lockring coming loose

Post by slowster »

It has been mentioned in at least a few previous threads - see especially Brucey's comments here:

viewtopic.php?p=1570945#p1570945

viewtopic.php?p=1279006#p1279006

I also recall reading that removing the rivets from a Shimano cassette to customise the ratios increased the likelihood of this sort of problem, and that it was important then to tighten the lockring to the full recommended torque.
Last edited by slowster on 8 Aug 2021, 11:09am, edited 1 time in total.
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NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Cassette lockring coming loose

Post by NATURAL ANKLING »

Hi,
I don't use a torque wrench at all despite doing mechanics at professional level.
Don't get me wrong some things do need to be torqued with a torque wrench, Like head nuts.
But I kind of think you need to just do the ring up a lot tighter.
I've never had one come loose, but I've only ever used six seven and eight speed.
I also cycle with a very high gearing meaning that I tend to do a lot standing especially up hills.

Biggest problem of bicycles coming out of shops, typically so-called trained halfords mechanics, The pedals you can take off with your fingers and the lock rings can be undone by blowing on them!
Just remember to use some grease on the serrations before you do them up.
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
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Stradageek
Posts: 1657
Joined: 17 Jan 2011, 1:07pm

Re: Cassette lockring coming loose

Post by Stradageek »

Cheers guys, I should have searched more diligently and anticipated an answer from our much missed guru. :(

Now that I know that I'm not making a fundamental mistake, I'll just tighten them regularly

Thanks again
Manc33
Posts: 2218
Joined: 25 Apr 2015, 9:37pm

Re: Cassette lockring coming loose

Post by Manc33 »

Today I put on a 7700 cassette and the lockring is so light it feels like you've got nothing in your hand when you're holding it.

The lockring says "40Nm" on it. Did I tighten it to that? Not a chance! It's obviously aluminium and, although almost certainly 7075 which, on a top cassette is probably as hard as the steel they use for the lockrings in the lower groupsets, I didn't want to chance it, so it's probably on at more like 30Nm.

Chris King makes an aluminium lockring and that says 30ft/lbs on it - which is also 40Nm. I am pretty sure when Shimano put 40Nm on, they mean don't go over that, whereas 30Nm ain't gonna come loose. On cheaper cassettes (and the 6500 I took off) I do put them at probably 40Nm but not that 7700, I am sure going off the weight of it there's no way it can take what it says on it. Why risk it.
We'll always be together, together on electric bikes.
rogerzilla
Posts: 2887
Joined: 9 Jun 2008, 8:06pm

Re: Cassette lockring coming loose

Post by rogerzilla »

I used to just put them on three or four clicks but noticed a bit of fretting of the splines, so I tighten them properly now.
Manc33
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Joined: 25 Apr 2015, 9:37pm

Re: Cassette lockring coming loose

Post by Manc33 »

rogerzilla wrote: 13 Sep 2021, 9:34pm I used to just put them on three or four clicks but noticed a bit of fretting of the splines, so I tighten them properly now.
The fancier cassettes like Dura Ace have a wavy washer that if anything, makes it a bit more confusing. Then you don't have those resounding clicks, more of a muted click as the notches rub together. I know from putting on BB cups at 40Nm using my now obsolete Park Tool beam wrench, that 40Nm is quite some force. 4KG on a meter wrench, 13.38KG on a 12", 16KG on a 10", 17.84KG on a 9" and, if you had hands like Superman, 53.5KG on a standard sized 3" allen key. :lol:
We'll always be together, together on electric bikes.
Stradageek
Posts: 1657
Joined: 17 Jan 2011, 1:07pm

Re: Cassette lockring coming loose

Post by Stradageek »

The title is now a bit misleading having established that I've not actually had a lockring come loose, just experienced the cassette spacers compressing slightly :D
Manc33
Posts: 2218
Joined: 25 Apr 2015, 9:37pm

Re: Cassette lockring coming loose

Post by Manc33 »

Stradageek wrote: 19 Sep 2021, 8:42am The title is now a bit misleading having established that I've not actually had a lockring come loose, just experienced the cassette spacers compressing slightly :D
Even XT cassettes (11-Speed) now use plastic spacers, which is really cheeky on a cassette costing around £100. :shock:

I suppose the thinner chains get and the better plastic tech gets, they are going to compress less with newer and newer offerings. :roll:

You could replace with metal spacers if ones exist in that exact width, but they would have to be like a bespoke thing made for that purpose and would probably be way overpriced, along with bike parts having doubled and even tripled in price on top of that. The best cassettes like Ultegra/Dura-Ace (at least on the old 9-Speed stuff) had metal spacers where compression is minimal/impossible. Ask me why I went back to 9-Speed :P
We'll always be together, together on electric bikes.
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Cassette lockring coming loose

Post by mattsccm »

If the lock ring undos regularly just check that it isn't bottoming out on the free hub before it is tightening the cassette against the back of the free hub. A thin spacer can go in behind if so. I have one casstte that is a touch narrower than others for some reason. The spacer works.
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