Clutch RD 1x10 Chain Length Question
Heckler with 11-36 XT 10 speed cassette, Saint clutch RD, 26T NW front ring
I was riding up a trail to the summit of a mountain yesterday so I shifted into my 36T.
As I was chugging up the trail I thought to myself that the 36T felt funny. I don't ride much in the 36T so I chalked this up to that fact and kept pedaling (dammit).
Shortly after this things seized and after looking things over I downshifted through the cogs, hopped on, and shifted back to my 36T.
A few pedal strokes later my derailleur hanger sheared off resulting in a bent RD and riding my bike like a Razor to get back to the car.
I have an ex-Saint RD with maybe 1.5 months on it so I'm going back to a Zee RD (first one was smashed up on a rock).
I have never had this particular issue happen before and I only started using a 36T when I went to 1x10.
I don't remember having this issue with my first Zee.
With respect to chain length the usual wrap big rear cog, wrap front (no RD in the mix), see where the inner chain plates would meet, add three rivets and blammo applies when it comes to a clutch RD, right?
The Saint was in freeride mode and I had the RD installed per the picture on page 8 in http://si.shimano.com/php/download.p...001-05-ENG.pdf but it seemed like a struggle to ever get it to shift smoothly to the 36T since day 1. Every other cog was great but the 36T always seemed to be difficult.
Shizzy happens with bikes, I get that, but I wanted to check in to see if I'm missing something here when it comes to 1x10, chain length, and 36T so I don't end up murdering another RD because of some nuance I'm missing.
If the new Zee struggles with the 36T off the bat I'm going back to a 34T or 32T cassette.
As long as the suspension is fully compressed. Slightly long is better than a little short.
Originally Posted by silentG
A little short shouldn't of sheared off your derailleur hanger. something else is up...
B-limit screw jacked up into the cogs could do this.
^just a guess.
I appreciate the feedback.
I didn't figure there was any special voodoo when it comes to chain length and 1x10. I didn't have my shock out and the suspension fully compressed (i.e. max travel on the rear) as that would make the chain too short.
The B-screw is possible, will check the wreckage to see if the screw has some marks on it.
The RD can handle a total of about 33 teeth, assuming it's a mid cage. You only need to handle 25. I would add a link or two. Check the position/attitude of the RD when shifted onto 36. If it looks too stretched, it probably is.
My name is Chris and I ride a Prophet 650b with a Lefty.
i didn't mean the screw itself. more like it was adjusted in a way that the jockey wheel was too close to the largest cog.
Originally Posted by silentG
I'm pretty sure I was within the 5mm gap specified by Shimano between the 36T cog teeth and the jockey wheel.
That is the most likely culprit though as being too close would definitely put pressure on the derailleur hanger.
Couple of pictures:
Saint and Zee RDs are short cages, with a 25T capacity.
Originally Posted by Prophet Julio
I've found with the Zee that chain length is critical when running 11-36, there's not much room for error, especially if you're on a full suspension bike with a lot of chain growth. The two times I set one up I did the around the largest cogs + 1 full link (3 pins) thing and then marked that spot. Then I compress the suspension and route the chain through the derailleur and hold it at the mark. In both cases (two different, but similar bikes) the derailleur would have been too stretched out, so I had to add another full link (3 pins). I'd rather it was slightly too long than risk damaging the derailleur and/or snapping the hanger.
I'm going to try that tonight or tomorrow when the new Zee gets here. That would make sense based on other things I'm seeing about Zee/Saint RD being pretty tight at 36T.
Shimano probably didn't design/plan around my massive power output either, heh
In case anybody comes across this thread in the future bvibert was correct. With the standard link and three rivets the Zee was fine with the suspension open. When I compressed the suspension though the Zee was really stretched to the point that I would bet that riding like this with the suspension active would in fact do what happened to my Saint RD.
Adding another three rivets to the chain made enough difference that with the suspension fully compressed the Zee was in a proper orientation while in the 36T.
I appreciate all of the feedback here as this was a good learning experience.
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