Various advice on the 'net suggests that 12 speed Shimano chains should be a few links longer than earlier systems. Places I looked suggested Quick Link + 4 links on a hardtail and + 6 on full sus.
But that doesn't seem to work - I bottomed out my suspension and went with plus 4 but the SGS mech was leaving the chain slack on 10-51 cassette. K's new bike *looked* like the chain was too short - mech was very extended in the 51 - but adding any links gave the same problem. I ended up re-setting it as the longest chain that still had some tension in the 10 sprocket.
Is the shimano instruction nonsense or am I missing something crucial?
Install only on to front and biggest rear, add a couple of links plus the quick-link?
Same as I did for 9, 10 and 11 speed...
Install only on to front and biggest rear, add a couple of links plus the quick-link?
Same as I did for 9, 10 and 11 speed…
Don't do this - things seem to have changed for 12 speed. Having set my chain up the old way like that originally, the shifting was finnicky and there was a bit of rumbling.
The shifting is much better and there's no more noise now I've reduced the B-tension and lengthened the chain. I'd say go for the absolute maximum length that keeps tension in the 10t cog. The plus 4 for HT and 6 for FS rule is nonsense - it'll be specific to each bike.
The shifting is much better and there’s no more noise now I’ve reduced the B-tension
See page 19 in the shimano instructions - theres a mark on the mech plate to help set the b-tension (back adjustment screw) which many people, including those making video guides, don't seem to know about. That's worked for me on previous bikes.
@spannermonkey
Yes, that diagram on p10 is the one I'd referred to (though I found it reposted on someones blog). Simply didnt work - when I set up like that there was no tension in the 10t sprocket.
Odd! I used those instructions just last week and mine is running beautifully
The only thing I can think of is different mech hanger designs putting the mech in a different position and affecting it somehow (one of the issues SRAM claim their UDH addresses - one of the new bikes has it and hadn't occurred to me before that mech hangers might vary in where they actually placed the mech)
I used to use the "X + 2" rules or whatever but these days I just pop out a shock bolt and cycle the suspension through its movement, you get better results that way.
The other half has 12s Shimano and I set it up as you say, plus 6 links. When the bike is stood or in the stand there's no tension but once it's being ridden it's fine. Been like it over a year and she's never complained about crap shifting.