Tight lockring, but loose sprocket ?
 

Hello!


I've recently installed a Shimano Deore m5100 11-51t 11speed sprocket to my mountain bike. My rear hub is a Shimano TX505.

I've tightened the lockring with the recommended 40nm, with a torque wrench.

After like a 5km ride on a bumpy road, I'm able to "rotate" the chain rings individually from each other on the hub, but just for like 1-2mm.

The interesting part is, my lock ring is still tight. I can't tighten it more with 40nm. If I tighten them with 50nm, it will be fine for another 5 kilometers, and then same thing.

I've allready tried to replace the included plastic spacers with steel ones, and looked all over the internet. The lock ring is not nesting on the top of the hub, it's pushing down on the sprocket. No broken rivets on the spider.

I dont have shifting problems, but I'm concerned if I keep riding like this, it will damage the hub and/or the sprocket.

Is it fine like this? Do anyone have an idea or a solution?


Thank you!

One possibility is notching of the hub splines by prior sprockets such that the new sprockets don't properly seat on the hub.
Pull all the cassette cogs off and examine the splines on the hub for notching, file off any protuberances
and try again. Also examine the lock ring threads in the hub to be sure no cross threading occurred- did this
once and it is hard to fix and not initially obvious when it occurs. Fortunately with most lock rings now plastic
this is less likely than with aluminum lock rings.

Sounds like the lockring is bottoming out on the freehub body. You could be merely torquing the lockring against the freehub body. It tightens enough to hold things together, but not enough to keep the cogs from moving.

I see no advantage using steel spacers over plastic.

You might have to add a shim before or after the cassette on the freehub body.

I've unpin some of my cassettes for custom gearing and have no issues with movement.

John

Plastic lock rings? Where on earth did you get this idea?

Another possibility is that your highest/smallest sprocket is not correctly aligned. Is the small sprocket tight, and the rest are loose?

Here’s another possibility that I’ve had to deal with on varying cassettes. And sorry…the picture below is the only one I could find to explain it. Sometime on the back side (or spoke side) of a cassette the bolt or rivets holding the gears together may not be flush, or flat. Depending on the hub…you may or may not need a spacer if the rivet/bolt is flush/flat. If I don’t insert the spacer, the lock ring bottoms out and doesn’t completely tighten the cassette onto the hub. I was able to purchase spacers of varying thickness at an LBS. If this is in fact your issue…remember that the spacer can go either before the cassette, or before the lock ring. And, it will likely require the shifting to be adjusted. — Dan

https://cimg5.ibsrv.net/gimg/bikefor...649d0b17df.jpg

Are you certain about the rear hub model. I'm not certain a 11 speed cassette will work with just any 9 speed Shimano rear or what ever yours is.

A FH-TX505-8 is a 8 speed free hub that is compatible with 9 speed cassettes, but I'm not sure if that moves on up the road in compatibility with 11 speed cassettes.

I've checked that, it should be able to pull down another at least one millimeter more before bottoming out.

What do you mean by not correctly aligned? I tought it can only be assembled in one way, because of the notchings.

The lock ring is not bottoming, it's pushing the casette down. If I put a 2mm spacer behind the casette, I might not be able to tighten the lock ring, because it cant reach the thread in the hub. Is it safe to use a narrower spacer behind the casette? I might be able to fit in 1mm.

It's listed to be compatible with 11 speed, picture is from shimano's website.


Also to answer some:
There is no wear on my hub, it's almost brand new. I've checked the threading on the lock ring and in the hub before, it appears to be fine.

Thank you for all your answers. I've made a video of the problem.
Please note that i'm pushing down on the pedal so the hub is tightened.
At the moment the casette is also tightened way above the recommended torque range, between 50-60 nm.
At 40 nm the movement is about the same, but it requires less force to jiggle.

youtube .com/watch?v=jDuhRjfeIOM
(please remove the spaces, I can't post links, new account)

With mountain bike cassettes, 8-11 speed is the same freehub body.

I think the Deore 11-51 cassette he's using is a Shimano mountain cassette. This article indicates that the Shimano 11-speed mountain cassettes are the same width as 10-speed road cassettes (I believe I've read elsewhere that that is accomplished by substantially dishing the largest sprocket; I'll see if I can find that reference too. I'll also see if I can find a better reference.)

https://www.lightbicycle.com/newslet...ty-Manual.html

If that's indeed the case, he may need the 1mm spacer normally required to use a 10-speed cassette on a 8/9/10-speed hub to take up the extra space.

I've tried to reply to you all, but it's awaiting some moderator approval. It's a mountain bike sprocket, on a mountain bike hub, on a mountain bike.
The shimano website lists the hub compatible with 11 speed. Should I try to install an 1mm spacer behind the casette? I've tried it with a 2mm spacer, but the lockring will not quite reach the hub to thread in.
I've already checked the thread on the hub and the lock ring, it appears to be fine. Also, the hub is almost brand new, no visible damage or wear on the splines so far.

Yeah, sounds like you need a thinner spacer.

Dan

Also I made a video of the problem, please note that I'm pressing on the pedal to tighten it.
It's on youtube, but I cant post links yet. watch?v=jDuhRjfeIOM

Thanks Dan, I'm going to try that.

This is the most likely explanation. The smallest rear cog only sits halfway on the end of the freehub, so it is easily misaligned during installation.

If anything, a thinner spacer would make the cassette looser, not tighter. I think that the smallest sprocket is not in position correctly.

You know, an 11t will not slide all the way onto the freehub body. So you could probably torque it without even using the rest of the cassette.

For this reason you might need a thin spacer behind the cassette, which has already been suggested above, so you are actually torquing the cassette and not just the first cog.

John

Edit added: While a bit OT, I’m running a 14t 11 speed 1st position cog with an 8 speed setup. It appears to be designed to interlock with an 11 speed 2nd position cog and an 11t lockring is also required since it sits off the freehub body.