RH Clark

Changing 10 speed cassette on my 26" wheeled Surly LHT. It's a Shimano HG50 in 11-36. It's exactly the same as the one it has now built up by Surly. I have the tool and chain whip. I am fairly handy with all sorts of tools. I'm not too afraid of over tightening but want to ask about dangers of under tightening. If you guys think a torque wrench is necessary, is the Park Tools one that's about $130 on Amazon the best option?

shelbyfv

Isn't it 40 Nm? That's more than you might think. I used a torque wrench on a cassette once and was surprised how much tighter 40 Nm was than what I'd been guessing. Still, I wouldn't buy a wrench just for this. I crank them down until they pop a half dozen times, very precise.

Eric F 

I've been working on my own bikes for a LOT of years, and have never had an issue with a cassette lockring coming loose. I go to the "pretty tight" setting in my arms. Unless you need an excuse to buy a new tool, a torque wrench is not necessary for this application (IMO).

mpetry912 

and use a dab of anti seize on those lockring threads.

you'll thank yourself when the time comes to remove it

/markp

oldbobcat

If you give the tool a good yank you will not be under-tightening. Aside from vibration, there are no forces on the lock ring that will cause it to loosen.

FBinNY 

Agreed. Plus it often helps to think based on potential consequences. If, for example the nut holding your front brake to the fork loosens and falls off the consequences could be very serious. OTOH what's the worst that could possibly happen if a lockring is somewhat under torqued?

FWIW - Some of the reasons we're seeing bike part torque specs has NOTHING to do with actual specific requirements. It's a problem of culture and communication. BITD folks learned mechanics by formal or informal training by a master of sorts. We learned to let the bolt size and thread pitch guide us, and assumed it was chosen based of the requirements. Of course, there were and still are times where that's not so, and we need a spec to override the default. Secondly, it's a question of communication. Manufacturers are now expected instructional data, and in the USA especially, can be held liable if products are assembled improperly. So, torque specs are included because how else can they communicate how not to over or under tighten.

I, for one, would appreciate torques to be spec'd as a range, with absolutes only offered as a max. or min. as relevant.

Iride01 

The only issue with under torquing the lockring on the rear cassette or even the centerlock brakes if you have them, is that it might loosen. And if you don't notice it, then after many rides with it loose you might find yourself replacing something. So, IMO, the likely worse thing is you just spend a little money. As well you'll probably be wondering why your bottom bracket is making an unusual noise and posting about it on BF.

If you do happen to find it loose before it causes an issue, then simply tighten it a little tighter than you did the previous time.

Kontact 

You guys have this all wrong. You dont tighten the lockring to keep it from turning. The heavily torqued lockring compresses the sprockets into each other so they hold position and dont clock into the freehub body.

Those super deep dents in the freehub splines? Under torqued lockrings.

Grease it and put it on TIGHT. Same with pedals.

A house would fall apart if the screws holding the studs together weren't locking the 2x4s into each other with high torque. Same idea.

icemilkcoffee 

I rotate the cassette until all the cogs are pushing snug up against the splines, then I tighten the lock ring.
Although Kontact's theory also has merit- if all the cogs are tightened against each other, then that avoids the problem of an individual cog pushing against and cutting into the hub body.

maddog34

huh... i always go for "Pretty Darn Tight" and sometimes "Really Darn Tight!".

i hate filing burrs off of freehub splines.... i ran into a 105 shimano hub a couple years back where the notching was so bad that just getting the cassette off became a project.. i went with "Way Too Damn Tight!" when i reassembled that one.....

Once the individual cogs start moving independent of each other, the wear begins in earnest....and what gets not considered is the wearing of the spacers between the cogs.
Drivetrain Road Grit is abrasives with cement made of old lube holding it together. CLEAN it off regularly...

Cleaning the bike is a great way to inspect for Loose things, Worn things, and Bent things too.

i even clean the spokes, one at a time... any loose ones are immediately apparent... i twist a bread sack tie onto the loose ones, then keep cleaning..

Eric F 

I guess "Pretty Darn Tight" is a more accurate setting - lol. I think the only place I've used "Really Darn Tight" has been threaded bottom brackets.

maddog34

i always use "one last good UUMPH".. on threaded BB's.

"pretty tight' is used on steering stem screws.

and then there's "I think i can get another UUMPH out of it!".. which is often found on steel ft. der clamps that actually deformed the seat tubes before the ham-fisting ended....
i found one of those a month ago... and somewhere in the garage is a fork with a crushed steerer tube... the top of the tube was flared from pounding too...

themp

Just get an inexpensive beam torque wrench:

https://www.amazon.com/ARES-8-inch-V...2s9dHJ1ZQ&th=1

Shimagnolo

I learned the hard way that a cassette needs a lot more torque than I thought.
I came home one evening with a loose cassette making a "thunk", every time I resumed pedaling.
So a torque wrench it is.

SoSmellyAir

No need for torque wrench to tighten cassette lock ring. Finger tighten using the lock ring tool, then 1/6 turn.


I personally finish with a 1/4 turn because Tony Marchand looks like he has stronger fingers than I do.

pdlamb

Happened to me on an event ride. I literally couldn't keep the chain on a gear. Fortunately, after finger-tightening, I was able to make it to the next SAG stop where the mechanic could tighten it for me. He gave me a really weird look!

So get it snug first, then make sure the lockring is Really Darn Tight.

Iride01 

I don't know that we got it wrong. We were just saying that a torque wrench isn't necessary. And how to deal with lockrings, nuts and bolts that come loose.

One of the indications of being too loose is exactly what you described. Though that would be found after the fact, but even then it's more a ugliness than a working issue. I suppose it makes some hard to pull off.

But it's a good point you made that maybe we were making it sound like it didn't need to be tight.

KerryIrons

Likewise, though I do use a torque wrench because I have one. That said, I have seen other riders with lock rings coming loose and cogs flopping around. It's beyond me how this happens, but it does happen. Pretty darn tight is about the right setting for those not using a torque wrench.

shelbyfv

FWIW, it's possible to tighten a loose lock ring enough to finish a ride. Use a shoe as a hammer and the flat head from a multi-tool as a drift in the serrations. Works surprisingly well and you'll amaze your riding buddies. The most aggravating part is getting the cogs realigned while juggling stuff on the roadside.

Kontact 

What you got wrong is suggesting that the only reason to get the lockring tight is to prevent the lockring from loosening. That knurled lockring wouldn't loosen if you tightened it with your fingers.

Those little cogs bear all of your weight charging up a hill. They aren't designed to do that by just hooking on the splines, but by becoming a solid part of the freehub body. This is exactly the same principle as what holds your crank arm to the the spindle or your pedals to the crank arm. Or your car's wheels to the hubs. The fact that the splined shapes get in the way of each other has nothing to do with how forces are supposed to be transmitted. If you don't lock them too each other the parts destroy each other, create more play, screw with your shiftiing and make your freehub harder and harder to fit new cogs on.

The only upside to not tightening the parts on your bike correctly is that you won't have to ask your dad to get them loose for you.

The spec is 40nM. Not "tight enough" or "use loctite". Use grease and those cyclists muscles.

Iride01 

Then I suppose I should have defined "it" better in my statement if you take that to only mean the lockring. Sure I'll take the hit for wording so nit-picking could take place.

Kontact 

How is undertorquing followed by "a little tighter" a recommendation to get the lockring tight? It doesn't sound like a recommendation to get the lockring fully torqued at all.

Iride01 

Now you are talking nonsense. No where did I state to under tighten the lockring. Everything else was about what to do if it turned out to not be tightened enough the first time.

Kontact 

So if you discover that your lockring isn't tight enough, like 20nM, and you then tighten it "a little more", like to 30nM; how is that going to get it to the correct 40nM?

Iride01 

Have you never read the directions on the back of a bottle of shampoo? "rinse and repeat"

You are also assuming that the ring is not tightened enough from the very start.

If you are suggesting that a torque wrench must always be used and that torque must be exactly 40nM, then I can only say I disagree.