Increase chain tension

02gf74

Just came home after test riding my 1x9 from 3x9 conversion and am pleased with the results.

SRAM X01 rear mech on hanger extender with 11 - 40 cassette, 32t narrow wide chainring replacing middle ring and using the same bolts. Chain shortened by 4 links.

All works well but I may have gotten away with 34t chainring.

Now the only issue is when on maybe the smallest 3 sprockets, there is not a lot of tension in the chain so if I stop pedalling, I can feel a notchines in the chain as it becomes very loose on the upper run (watching it I see it curve)., the slack is taken up, and depends on the number of ratchets in the freehub.

It hasn't come off but this can be addressed by having more tension.

The 9 speed X01 mech does not have a clutch so other than don't stop pedalling, what are my options, is a clutch conversion or a stronger spring available?

The Rookie

How did you set the chainlength? In lowest gear the rear mech should be almost horizontal and the lower run almost a straight line.

If it’s loosest on the smallest sprocket with the right length chain you need a mech with a longer cage, that said my super short cage XTR 9 speed copes just fine with an 11-40 cassette.

02gf74

Chain set up as you say. I mocked it up with an old chain, two less links would make it too short, it is FS frame. It is a medium cage, probably not much different to my 1x11 mechs, just about to measure.
75mm for 11 speed, 92ish mm for 9.

I didn't use the smallest sprockets with middle chainring but would have switched to the big one.

Unless there is an aftermarket gizmo, other than this spring thing attached to axle (these go bad k to late 80s when downhill was evolving) , or I can either modify pull on 11 speed clutch mech, it's an irritant I may have to get used to.
I ha e in the past modified shimano mech by drilling a small hole to relocate the main spring to increase tension but never have messed with sram mechs, and doubt it will solve it hence we would not have clutch mechs.

It is not entirely impossible that the spring has weakened over time.

Tommorrjrrow I'm doing a much longer ride near Clandon so should be a better test.

The Rookie

Perhaps try the correct method, biggest sprocket and chainring (not routed through the mech) and overlap my at least two (one pair) of links.

Do you have a side on photo in the biggest sprocket?

cycleclinic

Chain length is not affected by cage length. Size the chain for 1x the normal way like above.

02gf74

... Which is e actly how I sized the check. I used the old chain to check.

The Rookie

The old chain is irrelevant when you’ve changed the chainring and sprocket!

Side on photo?

02gf74