Paul_P

I was surprised the other day at how much torque the lockring is supposed to get, especially since it also clicks in place.

I put quite a bit less because I want to be able to remove the cassette with a roadside tool like the Unior Lockring tool, and I have no idea how much torque can be acheived with this tool.

mpetry912 

units conversion on torque values is no problem, conversion tables abound. This tool looks interesting Torque Equivalents - Conversion Calculator (engineersedge.com)

I'm of the opinion that torque wrenches are not really needed for every single fastener on a bike. I think torque became "a thing" when people started stripping out stem face bolts and seat mast binders, many of which are threaded into aluminum and easy to strip.

A feel for the tool and the material will make most torque operations superfluous on non-critical fasteners. That said, I do like to use the torque wrench on stem face bolts, and a few other critical items.

And car lug nuts ! 85-90 ft / lb

/markp

metropical

I do have a good feel for the hex set I have and the parts I'm working on.
Still, I'd hate to be wrong. Especially where the stem and stem extender are concerned.

SoSmellyAir

The Shimano original lock rings have a crush washer which helps them stay put, but I would still tighten to the specified 40 Nm.

Don't under-tighten the cassette lock ring! I did that with an aftermarket lock ring, the one that came with my Prestacycle Uniblock cassette. It does not have a crush washer, worked itself loose over time, and got wedged against a bolt mounting the RD hanger onto the frame, which locked up the freehub (relative to the frame) and caused the crank to suddenly lock up when I was pedaling, almost making me crash. I replaced it with an Ultegra lockring tightened to 40 Nm.

Paul_P

I'd be interested in learning what kind of forces are acting on the lockring to require such torque. I can see some lateral action from shifting and the chain often being at an angle to a cog, but that would just push inward and outward on the ring, not try to unscrew it, especially to overcome the detents. Or can the forces cause enough deformation that the detents can be overcome if the torque is less than 40Nm ?

I realise that there must be a very good reason somewhere for this torque to be explicitely marked on the ring. Maybe someone could confirm being able to unscrew it from 40 Nm using a tool like the Unior or similar.

SoSmellyAir

Vibration from the road transmitted through the wheel? In traditional automotive suspension terms, I would count the cassette as unsprung weight.

Russ Roth

Little late to this but my goto is the tekton, https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1
As a brand they're kinda in line with what craftsman was 40+ years ago, typically a mix of US or Tiawan manufacture licensed through other tool manufacturers and they seem to always get solid reviews. Little on the pricey side but I share my tools around where ever I need them and don't mind spending the money for something that'll work. Its been sufficient for any bolt or nut on a bicycle I would ever bother torquing. But I don't bother torquing lock rings and BBs, both are just made real tight.

rekmeyata

They use to make the old bicycle clicker wrenches sealed so you couldn't take it apart, but apparently they've changed that, which is good. In order to adjust it you have to have a torque wrench adjusting calibration tool, and takes some work to do it right. A calibration tool is not cheap, you might want to look at the prices of these tools; or you could take it somewhere and they can do it for you at a cost of course, not sure what that service cost but last I heard it were at least $25.

Wattsup

Just buy a digital torque adapter, ($35) the kind linked up-thread. Connect it to your clicker set to a certain torque, then go use it on a fixed bolt. Compare digital reading to clicker setting.

2_i 

The force propelling the bike is transmitted through a cog that the chain is on. It is being tortured during the riding, flexes, shakes, etc. The pile of cogs and spacers and maybe dirt in-between forms a 'spongy' structure, I can imagine. I think that this very high torque is there to push the cogs against the spacers and each other with such a force that, on one hand, the cogs stay as steady as possible and, on the other, that friction of the lockring against the smallest cog is such that it does not unscrew itself.

choddo

Could precession happen between the smallest cog and the lockring do you think? Normally one rotating body inside another but with the varying forces on the casette, I wonder…

2_i 

For sure the metal flexes and there will be tiny motions of cog relative to the hub, with lockring torn in 2 directions, all on small scale, but with effects potentially accumulating over time.