Shimano Mech Clutches and Chain Slap

Trying to reduce chain slap between lower part of chain and the bottom of chain stay. Its now more than I ever remember. It’s annoying but not a problem since it is slapping against the alu protector glued to the chain stay near the BB.

I thought the clutch was meant to stop this, but have noticed that after shifting to a larger cog the mech jockey wheel cage is held stiffly by the clutch, and the chain is taut. However after shifting to a smaller cog there is a small amount of play in the cage, and the chain is much more floppy, enough to slap the chain stay protector and cause the problem.

Is this down shift cage play normal? I have tried other bikes and they show the same – stiff after upshifting, some play after downshifting, so would seem to be so.

The slap started after I serviced and replaced the clutch with an old one from another mech. I was wondering whether a tighter clutch, a new clutch, or new mech with tighter pivots etc might solve.

I found the Shimano clutches to be poor
I swapped out the clutch on my XT and writhing few months it was goosed
I think the sram system works better
The mechanism means ye don’t need to switch it on and off
Plus I like the tension bolt for when taking wheel off etc

I’ll ask, just to be sure, but you know there’s a lever to turn on\off the clutch.

> You “may” need to remove a link from the chain
> You can increase the clutch tension (pop off the cover and it can be adjusted with an allen key)
> If the mech is oldish, i.e. over a year old, the clutch mech (spring) may have siezed. They seem to be quite prone to this. Pop off the cover and see how it looks.

The problem that nowadays with such huge sprockets on the cassette (42,45,50,52 etc) when your in a higher gear (9,10,11,12 teeth) there is just so much slack in the chain that needs to be taken up by the rear mech. And then you have to balance the amount of tension the clutch produces so you stop the chain slap without making it so stiff the gears won’t shift.

Not sure what the answer is, maybe cassettes that are something like 9-32 paired with a smaller front ring.

Can the Shimano clutches be adjusted (like the early SRAM ones)?

Have you accidentally switched your clutch off?

Is your chain a bit long?

Yes the clutch is on. I’ve checked the chain length and got 3 links overlap, which is a close to the shimano recommended 2 links.

The BB is quite high to the chainstay, combined with a 30T chain ring probably makes slap more likely than on other bikes.

3 links overlap, which is a close to the shimano recommended 2 links

It’s close, but it’s also 50% more than optimal.

The clutch is easy to service, and on most models is also adjustable.
OP’s sounds like it needs serviced. Plenty how-tos on YouTube.

What Bens and also Oldman say. Also, I’m sure the manual says that the on/off lever should be operated regularly. Word of warning though, do not be tempted to over tighten the screw that provides the tension on the clutch bearing – I adjusted mine after servicing it so that the derailleur had the correct torque (as per the manual) and the small piece of plastic, inside the housing,  that holds the adjuster in place snapped off subsequently at some point. The whole derailleur was replaced under warranty but I haven’t adjusted the new one at all, just operate the lever on and off a couple of times every so often and it has been fine for over a year now.

My XT M8000 mech is five years old, on its fourth set of jockey wheels. I remember being distinctly unimpressed six months in when the clutch started making grinding noises and becoming reluctant to shift outboard. A service, following one of the many YouTube tutorials, and subsequent yearly strip and rebuilds, means it’s never given me any problems since. I’d echo comments above about adjusting the clutch (with the XT model you don’t even need to remove the clutch cover, as you can access the hex bolt via a rubber capped port).