Ask a Mechanic: Adjusting Shimano Derailleur Clutch Tension

Brett wants to know: “ The clutch mechanism on my Shimano derailleur doesn’t seem to be working as well as it used to. I’m hearing a little more chain noise.  Can you show me how to adjust the tension on the clutch?” 

 

We’ve all been a little spoiled with quieter drivetrains and fewer dropped chains thanks to clutch mechanisms that were introduced by Shimano and then later adopted by SRAM.  It has been one of the most significant advancements we’ve ever seen in the mountain bike industry, and has made a lot of people very happy.  That said, it is just like any other moving part on the bike and needs service from time to time.  If you feel your clutch isn’t working as well as it should, or just want to eliminate a little more noise from chain slap, here’s how you do it.

You can make this adjustment with the clutch in the on or off position, but it’s easier if the clutch is off.  First up, using a 2mm allen wrench, remove the three screws securing the clutch cover.  Once the cover is removed, use a 5.5mm open wrench to tighten the small hex bolt that increases or decreases the tension on the band around the clutch.  To add tension turn the bolt clockwise.  Shimano has made this even easier on their new XT and XTR rear derailleurs.  All you have to do with these is remove the cap on the bottom of the clutch assembly and use a 2mm allen through the opening to make the adjustment.  You’ll be surprised at how much of a difference just a quarter of a turn makes, so start with a small adjustment and work up to the tension you desire in the clutch.  If you are making the adjustment with the clutch in the off position, turn it on to check the tension.

When turning the clutch, place your thumb over the top of the cam so it doesn’t pop off the top of the cam mechanism.  If it pops off, that usually means you have a little to much tension on the clutch band.  When checking the tension you want the pulley cage to offer resistance but remain smooth.  Adding too much tension can also affect your shifting performance.  Once you have the desired amount of tension set on the clutch, all that’s left is to replace the cover and get back out on the trail.

2015-12-16T12:11:32-08:00