NoWhammies

Hi. I am not sure what I have done, and I'm hoping someone here can give me some guidance.

I took the 10 speed Shimano - Ultegra I think - cassette of my wife's bike to clean it. I removed all cogs and spacers, even the spacers that were on the freehub, and cleaned them with a degreaser. All went well, including putting everything back together again EXCEPT...

Now when the chain is in the big ring up front and the largest ring on the back, in short cross-chaining, the chain keeps hoping between the largest ring and the second largest ring on the rear cassette. I can't figure out why, as I never touched the barrel adjuster during the cleaning and the chain seated properly before I did any work.


I might have made matters worse, because I started mucking around with the barrel adjuster (after) to try fix the problem and I didn't fix the issue. If anything the bike/chain ring just seems to make even more noise now.

Anyone have any ideas on what the problem might be? And what the solution might be?

Thank you.

woodcraft

Possibly the spacer behind the cassette was left off, putting the cassette further toward the center of the wheel.

After checking that, that the lockring is tight, the wheel is seated properly, & the cable ferrules are seated

manually pull the shift cable to move the RD inboard & adjust the limit screw if necessary so the pulley wheel is under the largest cog.

Then adjust the cable tension so The RD shifts into the largest cog, & after that fine tune so it shifts well in the middle ones.

NoWhammies

Just doing a bit of internet reading/research. Is it possible I made an error with my spacers? I assumed they were all the same size (with the exception of the one on the freehub) and didn't keep track of them separately.

The chain does shift/fit between all the cogs properly though. Thank you.

smashndash

First, confirm that, if there was a spacer behind the cassette before, it's still there.

It's possible that the cassette had previously dug into the freehub and wasn't totally flush with the end of the freehub, or maybe there was some grit behind it. If the gears are shifting perfectly in all the other gears (no skipping or laggy shifts), then try adjusting the limit screw. Be careful not to let it out too much - don't send the mech into the spokes.

NoWhammies

I think I figured out what the issue is as I getting ready for bed last night. As an aside I find it amazing how calming the mind helps solving problems. Anyway...

@smashndash I believe you might have hit upon the solution. There are TWO spacers behind the cassette. I put both of them back, but I think I put them in the wrong order. The two spacers look something like this:



I put the solid spacer in front of the notched spacer. This is preventing the cassette from sliding all the way down. I think I need to put the smooth spacer behind the notched spacer on the hub. Then the cassette. At least that is what I'm hoping will solve my problem. Going to give it a try when I get home tonight.

redlude97

You could also just slightly tweak the limit screws and barrel, an easier fix to me than pulling the cassette off again

smashndash

I think you're giving me too much credit here. I didn't realize there was a two spacer system out there. But from some quick googling, I infer that you have a 9/10 speed Shimano freehub:

Notice the notching on the "wall" of the freehub. I believe the notched spacer is supposed to go first and interface with those notches, to turn the freehub into a 10speed freehub:

Notice the smooth wall. The 1mm smooth spacer interfaces with this smooth surface. Then, you slide your cassette on. I'm not sure what you mean by "in front" or "behind". But my opinion is that the order when installing is: notched spacer (with notches facing towards the center), smooth spacer, then cassette. If you have shifting problems at this point, it could be that your limit screw was set when the spacers were in the incorrect configuration.

NoWhammies

Thanks for taking the time to do a bit of searching. I appreciate it.

I currently have the hub set up as you describe. Notched spacer followed by smooth spacer followed by cassette. I thought this was the way the spacers came off the freehub. My thinking was to reverse this. But now, base on what you're writing, I'm second guessing myself. I'll also take a closer look at the freehub.

I don't think have rebuilt the cassette improperly with spacers as the chain shifts smoothly between the cogs. It's just the final, largest one that is giving me issues.

When I first put the wheel on the bike, the chain wasn't even seating in the largest cog. The chain was just riding up above on top of the teeth. It was only after taking the cassette off, re seating it, and tightening the lock bolt that the chain and teeth lined up.

smashndash

Have you tried loosening the limit screw? Let the derailleur get a little closer to the wheel and see if it solves your problem.

ThermionicScott 

The intent of those three notches on the spacer is to accommodate the rivets used to assemble many Shimano cassettes (they were actually tiny bolts at one time.) The notches face the backside of the cassette, and line up with the rivets to make sure the cassette can slide all the way in. If your cassette doesn't use rivets like these, then it doesn't matter which way you put it on.



If you can, please take a picture of your assembled cassette from the side, like the one from slowtwitch. I'm wondering if you mixed up the spacers, and used a thin one between the largest two cogs when you needed a thicker one. That could cause the chain to catch on one when it's supposed to be riding cleanly on the other.

88Tempo

I had to notch a spacer yesterday as I had an old although in good condition 7 speed cassette with the screws holding everything together and without notching the spacer it would not seat far enough for the threads to engage.

mitchmellow62

Aren't the largest three cogs of a 10 speed Ultegra cassette mounted on a spider and can't be dismantled? 10 speed shimano is out of my experience (I've stopped at 9) but that is the way they are pictured in the technical documents. It sounds likely that NoWhammies has it back together correctly. The largest 3 cogs are stuck together and can't be altered. The other loose spacers are all the same size. Also, the 2 spacers between the cassette and the base of the hub body are probably correct. I don't think its that unusual to have to tweak the indexing (limits and tension) after dismantling and reassembling the wheel/cassette. It may be a little unusual that the problem was at the largest cog but that could be a red herring. If it were me I'd be sure my assembled cassette matched the exploded view in the technical document and move to setting the high and low limits and adjusting cable tension.

10 speed CS-6700 technical document: https://si.shimano.com/pdfs/ev/EV-CS-6700-2924B.pdf

NoWhammies

Thank you everyone for your time and assistance. Very much appreciated!!!

I managed to get the cassette and bike running again. And I am not sure what I did to fix things up.

I took the cassette apart when I arrived home from work and put it back together again. I rechecked everything, including how the two spacers were on the freehub. Thanks to my neighbour, I took a look at his 10 speed setup and determined the two spacers need to go notched spacer, then smooth spacer. After that I slid the cassette on, tightened everything up, and put the wheel back on the bike.

Everything seems to be rolling smoothly now. Gears are changing and the chain sits nicely in the rear cog.

My wife is taking her bike out for a spin after work today, so I'll get an updated field report then. Thank you once again. If she has issues, I'll be sure to report back.

ThermionicScott 

Correct, not all cassettes have the need for those notches, but Shimano might as well provide them in a common part. If the biggest 3 cogs are on a carrier, you're probably right that the poor shifting has more to do with limits and cable tension.

mitchmellow62

This thread has been interesting and added to my meager knowledge base. I don't know if I will ever go beyond 9 speed but its nice to know just in case. I've done some research and want to clarify some points. Based on what I've been able to find, the only situation where the two spacers external to the cassette are used is when a 10 speed cassette is used on a 11 speed hub. The thinnest spacer (without the notches) is 1.0 mm and comes with all 10 speed cassettes. It must be used whenever a 10 speed cassette is used on a 8/9/10 speed hub. The additional notched 1.85 mm spacer is needed when a 10 speed cassette is installed on a 11 speed hub because the hub body is that much longer than a 8/9/10 speed hub body.

I haven't seen anything about the spacers having to be placed in a certain sequence or with the notched spacer "facing" a certain direction.