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Currently building up a new hardtail using a 2016 Scott Scale 720 plus frame and I have hit some issues on the drive train. The bike was originally 2x and I've bought bits to build it up as 1x but slightly worried now that I've made a mistake...
The jockey wheel is hitting the cassette, and the b screw isn't long enough to adjust it out of the way.
Also I wasn't able to get into the lowest couple of gears, and the chain was jumping off the chainring when changing up to the lower gears too, although because of the jockey wheel issues I wasn't able to test the gears very easily so I'm not entirely clear when the chain was starting to come off.
It's got race face evolve cranks, on one 32t chainring, sram XX1 11 speed derailluer and X1 shifter, and a shimano 11-46 cassette.
Checking the chainline it measures 49mm, which seems to be right, but reading up on the spec of the XX1 suggests it's only suitable with a 10-42 cassette.
So is it right to think that putting the correct cassette on should let everything work correctly (reach all gears, chain won't jump off, b screw adjustment will be sufficient), or is there something else I need to consider?
You’re gears will be totally crap until you sort the b-tension issue. Have you set the chain length properly too? Sram stuff is very sensitive to this
Welcome to the forum mate.👍
Could try a longer b screw, or one of those cheap Chinese mech hangers that space the mech away from the cassette?
Check the mech hanger is straight too, as a matter of course.
Check rear hanger alignment as its critical to shifting and use a mech hanger extension to sort out the big sprocket issue
Longer b screw needed, then you'll get all your gears.
I have taken some links out but all I did was remove enough links when in the highest gear to bring the derailleur off the cassette i.e. remove slack from thw chain. I've heard some people decide chain length when in the lowest gear but as I haven't got that yet this was my only option - can re-check when all sorted.
I have looked at the goat link style adaptors and may need one as the b screw isn't landing square on the tab it pushes against when at full extension and may slip off, but even if I manioulate the mech manually it just doesn't look like it would expand enough for the 46t cog, which is why I started reading speca and found that they state 10-42t - not sure if it's possible to work with a larger cassette than recommended?
My SRAM NX 11 speed derailleur is only rated up to 42 tooth rear sprocket.
I would need a 12 speed mech to go bigger.
Presume the higher end kit is the same so you would either need a 12 speed mech, which I understand works with 11speed shifters, or use a 42 cassette.
And the best way to check mech alignment is.........?
Xx1 11 speed mech works on a Hope 10-48.
You size a chain by bypassing the RD so you should have been able to go large/large as the RD wouldn't have been used. If you sized through the RD then that is likely your issue.
Presume the higher end kit is the same so you would either need a 12 speed mech, which I understand works with 11speed shifters
Pretty sure they don’t, but happy to be corrected.
teethgrinder that's good to know, suggests the mech hanger thingy (giat link copy) might do the trick.
lucero I'm still not sure exactly how the chain length should be set if in fact i bypass the derailleur - can you/someone clarify?
Hard tail, large sprocket on the front, in your case, the only chain ring, large sprocket on the back, don't outy the chain through the derailleur, where the chain meets, add another two full links, cut, thread thru derailleur this time and join together
Try a hanger extender rather than just cranking out the B-screw. You get better chainwrap that way
The tech manuals on the Sram site show how to set the chain length too. As the top jockey wheel is far from the pivot having the wrong length puts it in the wrong place
Thanks all, good advice - have ordered a mech hanger adjuster for a tenner off ebay and will correct the chain length and re-try.
And the best way to check mech alignment is………?
With a rear mech hanger alignment tool.
Got an update on this - I got the mech position correct by buying the mech hanger from a 710 plus which has 1x drivetrain as standard, and this let me adjust the b screw correctly.
So I followed the sram manuals for chain length and mech set up and all seemed well, until I got into the 3 largest cogs on the cassette, at which point the chain would ride up on the chainring and come off. The other gears shift up a d down fine.
I've taken a couple of photos, and it's pretty clear on the close up that the chain isn't engaging with the teeth on the chainring as i shift ip to the larger cogs.
I have checked chainline and the chainring is 49mm which seems correct from what I've read, and the cassette is 47mm. Research suggests that 49mm is optimum for this, but I can't see a 2mm spacer behind the cassette stopping this problem given that it's happening in the top 3 cogs (more than a 2mm range).
It's a clutched mech and onone 32 narrow/wide ring. This is happening in the work stand though, nothing is getting bounced off.
Here are the pics - looking for help as I've run out of ideas...
id bung some 2 or 3mm chainring spacers in and space the chainring in a bit if your frame has enough clearance.. and see if that fixes it..
after fiddling about for ages back in the days of 10 speed expander cogs with back pedal issues I run all of my 1X bikes with chainring spacers now as I find it gives me a better chainline for the gears i ride in most of the time..
How many miles on the chainring?
As said, try spacers and/or new chain ring perhaps.
Hope range extender large sprocket kits TREX come with a longer B tension screw for this very reason.
I can see now why your mech didn't work until you replaced the hanger - the 2016 Scale 720 came with a Shimano Direct Mount hanger, which doesn't work with Sram mechs.
As for your chainring, how old is it? And is it an 11 speed one, or a 10 speed one? It should play ball but if it's old (which it doesn't look like) or it's for 10 speed a new 11 speed chain may not fit onto it nicely. Sounds unlikely though, and it might be worth spacing the chainring towards the frame more. Because you're using a triple crank that's been adapted it might just be that the chainring is too far out and messing up the chain line.
I don't use Shimano so no idea if this is drivel or not, but don't you get a 2mm spacer to go behind the cassette when running 11 speed Shimano??
Or fit the BB spacer on the non drive side?
Edit - Just re-read the OP and noticed its a 2x crankset. This will be the issue and as said you'll need to space the chainring inboard a couple of mm and use longer chainring bolts
Good shout munrobiker, I checked the spec of the chainring and it's actually only 10 speed. Got an 11 speed sram on order from evans, along with a spacer to move cassette out a touch - hope that does it.
Chainring position is bang on, and moving in board would foul on the tyre (3") in the big cog, so will move the cassette out a bit and cross fingers.
Thanks again for tips.
How do you space the casette out . Assuming that it's tight on the freehub already then if you fit a spacer you won't be able to get the lockring on .