How oh how do you get a lockring off?

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Brucey
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Re: How oh how do you get a lockring off?

Post by Brucey »

colin54 wrote:Thanks Brucey.
Would you say using a torque wrench gives you a more likely satisfactory outcome (just out of interest, not that I'm going to bother getting one) ?


Honestly I don't know. I suspect the clamping pressure on the sprockets is highly variable (for any given torque) and -not least because plastic spacers creep (collapse) under sustained load- the clamping pressure doesn't stay constant anyway. My hunch is that if you use a cassette with metal spacers, fitted with a lockring which includes an intact shim, using grease and a torque wrench, this is about as good as it gets. It still might not be that consistent though!

cheers
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Mick F
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Re: How oh how do you get a lockring off?

Post by Mick F »

My torque wrench clicks when the set torque is reached.
When I've tried to use it on a lockring, the click from the wrench is masked by the clicks from the lockring. :lol:

I just do mine tight. Never had an issue in use, and they all come undone without issue either. The very idea of putting 36ftlbs into a lockring fills me with horror.

Years ago, I cross-drilled a lockring tool so I could use a tommy bar. The bar is about a foot long and works a treat. I'll dig it out later and take a photo.

The bar is actually a home-made drift for removing bearing races from the head tube. I heated the end up and forged a hook, then filed it accurately, then heated it to red hot and plunged it into cold water to harden it.
Mick F. Cornwall
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Mick F
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Re: How oh how do you get a lockring off?

Post by Mick F »

Here you go.
Cross-drilled the crank remover too.
IMG_0307.jpg
Mick F. Cornwall
colin54
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Re: How oh how do you get a lockring off?

Post by colin54 »

Thanks for your candour Brucey ! I'll stick with my simian method for now. I don't know what would fail first on the lock ring if grossly over-tightened, the threads on the lock-ring or freehub itself, possibly the outer flange would distort /shear .
I don't think I've ever encountered a shim to go under it on all my 7/8 HG 40/50 speed stuff, black plastic spacers as well by the look of them.The loosening of those by compressing is not something I've noticed before and something to be aware of, thanks.
Last edited by colin54 on 23 Jan 2021, 10:21am, edited 1 time in total.
Nu-Fogey
Pebble
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Re: How oh how do you get a lockring off?

Post by Pebble »

Mick F wrote:My torque wrench clicks when the set torque is reached.
When I've tried to use it on a lockring, the click from the wrench is masked by the clicks from the lockring. :lol:

I just do mine tight. Never had an issue in use, and they all come undone without issue either. The very idea of putting 36ftlbs into a lockring fills me with horror.

Years ago, I cross-drilled a lockring tool so I could use a tommy bar. The bar is about a foot long and works a treat. I'll dig it out later and take a photo.

The bar is actually a home-made drift for removing bearing races from the head tube. I heated the end up and forged a hook, then filed it accurately, then heated it to red hot and plunged it into cold water to harden it.

They seem to be able to take it, in my earlier video (pg3) I'm guesstimating I would have been putting 60ish lb ft into tightening it. TBH I thought I had expected to strip the treads at that effort.
Brucey
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Re: How oh how do you get a lockring off?

Post by Brucey »

colin54 wrote: I don't think I've ever encountered a shim to go under it on all my 7/8 HG 40/50 speed stuff, black plastic spacers as well by the look of them.The loosening of those by compressing is not something I've noticed before and something to be aware of, thanks.


shims ('lockring spacers' in shimano-ese) only come with the posher cassettes but you can buy them separately.

https://si.shimano.com/pdfs/ev/EV-CS-7800-2253.pdf

https://www.sjscycles.co.uk/cassettes/shimano-duraace-cs7700-lockring-spacer-for-12t-sprocket-11w-0200/

they come in different sizes for different lockrings. I'm not altogether sure that the net result is very much better than using a lockring with worn serrations.

You can check how tightly held the sprockets really are by using a couple of chain whips; they will move within the spline backlash, at a torque which varies with the clamping load.

If you overtighten a lockring, a common failure is that the end of the freehub body breaks off. Not all freehub bodies are made equal of course.

cheers
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colin54
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Re: How oh how do you get a lockring off?

Post by colin54 »

[quote="Brucey"

If you overtighten a lockring, a common failure is that the end of the freehub body breaks off. Not all freehub bodies are made equal of course.

cheers[/quote]
Thanks Brucey food for thought, I might have to lay off the bananas next time ....
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531colin
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Re: How oh how do you get a lockring off?

Post by 531colin »

colin54 wrote:........ I might have to lay off the bananas next time ....


I think you'll be all right, it seems to me you can recognise the difference between a crane and a bike.... :wink:
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531colin
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Re: How oh how do you get a lockring off?

Post by 531colin »

Brucey wrote:.........You can check how tightly held the sprockets really are by using a couple of chain whips; they will move within the spline backlash, at a torque which varies with the clamping load.....


All my freehub bodies are steel. Even with cassettes built up from bits (ie no rivets), all I see are bright witness marks where the individual sprockets bear on the hub body.

I know its different with alloy hub bodies, you can get a lot of wear on the edge of the splines; but can you realistically exert enough clamping load on the sprockets (and plastic spacers) so that the chain load on one sprocket is shared out between the stack of sprockets? Because if you can't, what is the purpose of tightening the lockring to a high torque?

With my steel hub bodies, I just nip up the lockring so that the cassette doesn't fall off.
thirdcrank
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Re: How oh how do you get a lockring off?

Post by thirdcrank »

Only from reading reviews etc., I know that a lightweight tool exists to undo a freehub lockring in situ when out on the road, eg to be able to replace a drive side spoke.

I've checked the Spa www and they advertise this:-

NBT2 (Next Best Thing) Cassette lockring remover


https://spacycles.co.uk/m13b0s72p595/NB ... ng-remover

I see it's now even more heavily discounted. The description includes this from a 2006 CTC review:-

The NBT2 is NOT suitable for use with super lightweight [stupid-liteTM] alloy racing frames, where the deraileurhanger already self destructs with normal use.
Prior to first time use it is recomended to check with conventional tools that the lockring hasn't been tightened way over the recommended torque by some hamfisted mechanic, to prevent overloading the dropout.


It sounds like a different world to using scaffold tubing to add length to tommy bars. Now, we are edging into the old FAQs about removing stubborn freewheels.
pwa
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Re: How oh how do you get a lockring off?

Post by pwa »

531colin wrote:
Brucey wrote:.........You can check how tightly held the sprockets really are by using a couple of chain whips; they will move within the spline backlash, at a torque which varies with the clamping load.....


All my freehub bodies are steel. Even with cassettes built up from bits (ie no rivets), all I see are bright witness marks where the individual sprockets bear on the hub body.

I know its different with alloy hub bodies, you can get a lot of wear on the edge of the splines; but can you realistically exert enough clamping load on the sprockets (and plastic spacers) so that the chain load on one sprocket is shared out between the stack of sprockets? Because if you can't, what is the purpose of tightening the lockring to a high torque?

With my steel hub bodies, I just nip up the lockring so that the cassette doesn't fall off.

Me too. They don't go on at high torque (probably a lot less than is written on the packet by the sound of it) and they don't display problems in use and don't come loose either. I have been using cassette lockrings since the 1990s and never had this problem.
Brucey
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Re: How oh how do you get a lockring off?

Post by Brucey »

531colin wrote:
Brucey wrote:.........You can check how tightly held the sprockets really are by using a couple of chain whips; they will move within the spline backlash, at a torque which varies with the clamping load.....


All my freehub bodies are steel. Even with cassettes built up from bits (ie no rivets), all I see are bright witness marks where the individual sprockets bear on the hub body.

I know its different with alloy hub bodies, you can get a lot of wear on the edge of the splines; but can you realistically exert enough clamping load on the sprockets (and plastic spacers) so that the chain load on one sprocket is shared out between the stack of sprockets? Because if you can't, what is the purpose of tightening the lockring to a high torque?

With my steel hub bodies, I just nip up the lockring so that the cassette doesn't fall off.


I have seen worn steel freehub bodies but this takes a long time to occur even with loose sprockets. For sprockets which are clamped to any meaningful extent, they may not be on the move all the time, only when you are putting in an above average effort. Obviously this will vary from rider to rider. When I see 'badly bitten' freehub bodies this can only have occurred two ways;

1) the lockring wasn't tight enough for that rider and the sprockets were on the move from the start or
2) the clamping force on the sprockets eased over time.

I think 2) is very common; lockring serrations may mean that the clamping force isn't quite as high as you would like from the start, and between creep in plastic spacers and wear arising (from movement) the clamping force is only ever going to go one way.

IMHO the clamping force doesn't have to be enough to cause it to be shared with neighbouring sprockets; it should be enough to prevent the sprocket from moving around. I think that the wear arises from small radial movements of the sprocket under load, and that if the clamping force is enough to suppress that most of the time, it is 'job done'. With plastic spacers I don't think they are stiff/creep resistant enough to sustain enough clamping load to suppress movement under all conditions; the most violent of efforts will always produce some movement rather than none. It is just a question of having enough clamping load that the in-service movement isn't enough to cause problems in the intervals between the lockring being retightened.

Radial in-service movement may be driven by chordal effects (which generate net radial thrusts on the sprocket) in some cases; thus the torque on larger sprockets can be higher, but the chordal effect is less; thus the worst wear in the interface is commonly seen with small and middling-sized sprockets rather than larger ones, perhaps...?

FWIW I would probably have designed the spline with sloping faces rather than radial faces; this would tend to keep each sprocket centralised even under load (cf sturmey-archer IGH sprocket mounting for example). Mountings of this type are inherently more stable when subjected to combined torque and radial thrust loads.

BTW it isn't necessary to undo the lockring on tour, if you use shimano hubs; provided you have cone spanners the axle can be withdrawn and the freehub body removed (with the cassette still attached). This way you can have your lockring properly tight and not have to worry about getting it undone.

cheers
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pwa
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Re: How oh how do you get a lockring off?

Post by pwa »

Just to add, having said that I have no problems with cassettes when the lockring is installed without much torque, my cassettes have generally been ones with metal spacers, if that makes a difference. Wear on the steel splines has been minimal to non-existent.
alexnharvey
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Re: How oh how do you get a lockring off?

Post by alexnharvey »

Has anyone tried the Zinn-Pedro's chain vise grips?

https://cyclingtips.com/2020/10/pedros- ... s-updated/
Brucey
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Re: How oh how do you get a lockring off?

Post by Brucey »

alexnharvey wrote:Has anyone tried the Zinn-Pedro's chain vise grips?

https://cyclingtips.com/2020/10/pedros- ... s-updated/


this tool has the feature that the engagement with the sprocket is (apart from width) fixed, rather than articulated. This means that in most cases the load will be borne on a single sprocket tooth each side, rather than two as the jaw shape suggests should be the case. This kind of loading will be OK most of the time but if you meet an obstinate case, damage may arise.

FWIW the 'chain whip substitute' cassette tool which is sold in decathlon has three pins which engage with the smallest sprocket; this may avoid the possibility that torque between the sprocket and the freehub body causes the smallest sprocket to 'ride up' on the spline ends and interfere more than normal with the lockring. In other words it may result in a lower torque being required to release the lockring.

cheers
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