I'm running a SRAM GW Eagle crankset (12 speed) on a Niner Air9 Carbon hardtail. This is a non-boost crankset.
A lot of my riding requires the lower gears (and yes that includes granny too).
The chainline in all but the highest gears is visibly really poor and the graunching noises it produces in wet/ gritty conditions is awful. There's some serious grinding going on! On faster runs where I'm using the higher gears all seems ok, but thats not reality
I've only done 150 miles on the brand new setup and the wear marks on the chainring are quite noticeable like someone has taken a file to the teeth.
Not sure what options I've got. The chainring runs pretty close to the chain stays so moving the chainline in (even if the components existed), doesnt seem much of an option as it'd only move the chainline inboard by maybe 1 gear width... all the problems come from the chainline running to the gears higher up the cassette.
Is the design of the standard SRAM chainring the issue with its 'hooked' design? Would a swap improve the problem? That clearly wont address the chainline issue but would it improve the awful sounds it produces?
Anyone else share this problem?
What rear hub are you running - is it a proper boost one or a converted non boost one with a spacer on the driveside?
Also, what size chainring have you got - if you go down a size - say from 34 to 32 - then you’ll use the bigger cogs less in your cassette as you’re moving the range down (but not changing the range obviously) by a couple of teeth
IME the Sram chainrings are great. If you have a steel one it’ll last a very long time.
Thanks Joe
I take your point about dropping a couple of teeth but it won’t change the situation significantly as there are about 4 gears that cause the grinding noise
I’m on a non boost hub and 32 teeth at the front
If I could increase the chainring offset AND reduce the number of teeth that could help but as I say I don’t see and options for the former and the gap to the chainstay is pretty tight
Is it noisy in the 50t or the 10t, it's not entirely clear. You say it's noisy in the high gears, but I get the impression you mean the biggest sprocket/lowest gear?
Changing chairing size wont affect the noisy gears, but will change how much you use them which might help overall because you'll spend more time in the nice gears.
Mine's noisy too (boost + boost so same effective chain line). I think the chainline is symmetrical, it's just noisy in the bottom gears as there's a lot more teeth to rub against so the 10t with an equally bad chain line is just naturally quieter.
You say it’s noisy in the high gears, but I get the impression you mean the biggest sprocket/lowest gear?
I'm struggling with this too. I think he means the opposite of what is said.
If you can't push the chainring inboard anymore because of the chain stay clearance there aren't really any options.
When you have a close look at the range of movement across the cassette and the difference in chainline, it's frankly amazing that 12spd works. It's a bit agricultural, but it does work. I don't think I could use it on the road though.
Apologies
The noisy gears are the big rings.
It’s a strange evolution really over the past few years. 9 speed - pretty good but needed an extra gear to cover all eventualities. 10 speed - probably where they should have stopped as most riders could run 1x. 11 speed - I’ve no experience. 12 speed - certainly my experience isn’t great
