On-One 456 - chain dropping off (single ring)

aserota

Hey all,

When shifting into the top 2 gears (smallest rear cogs) my chain is hopping off crank side (not BB). I'm not running any sort of chain guide and am open to that; the bike is clean and shifts well up to the smaller cogs

Setup:
1x10 setup with firex crank, SRAM x0 rear mech a SRAM x7 shifter
One-one evo2 frameset

Would you recommend a specific chain guide? Or can you see any major issues with the component setup here?



More here:
https://photos.app.goo.gl/sryfaxEtwTW8c2A52

cooldad

Is it a narrow wide chainring?

aserota

I'm not sure off hand, I'm away from the bike tonight but will grab a better pic with chainring details then. It looks like this one here:
https://www.chainreactioncycles.com/mob ... 8?mx101=nf

so then it's not specifically for 1x which could be the issue?

The Rookie

Yup.... I’d go as far as to say is.

cooldad

I concur with my learned colleague.

Get a narrow wide and try again.

steve_sordy

I can see that you have a clutch mech. That added to a narrow/wide chain ring should pretty much prevent chain loss.

Most chain loss is caused by the chain whipping up and down on rough trails and developing a loop that moves towards the ring and then coming off. The clutch mech helps to stop the loop developing and the N/W helps stop the chain from coming off. The two together have been revolutionary.

But there are two other causes of chain loss that come to mind immediately

1)Have you checked the chain length? If it is too long, then not even a a clutch mech and a n/w ring will stop the chain from coming off on bumpy trails. It is at its most vulnerable when in the smaller cassette gears. There are many ways to set the chain length and there was a thread on it recently. This is what I do. On a 1x, put the chain in the biggest gear at the back and check to see what angle the mech arm is at. It should be at about 45 degrees pointing forward. If your bike is a full suss, there is a chance that under full compression, the suspension design may extend the rear of the bike and damage the mech. To check this, fully compress the rear suspension (let the air out of the shock, or if it's a coil shock, get the help of a heavy friend). As long as the mech arm still has some give in it, you'll be fine.

2) How is your chain line? The ring needs to be in line with the centre of the cassette. To make it easy, most manufacturers give you a measurement from the centre of the bottom bracket. But when converting from 2x to 1x I had to go back to first principles and measure the width of the BB and shuffle the spacers around until I got what I wanted. If the spacers I have available don't permit the chain line to be in the exact centre of the cassette, but either side of the centre line, then I would opt for towards the bigger gears.

The Rookie

This Video is pretty useful https://www.youtube.com/watch?v=W9dwv78cMYc

If the chain is too long the mech can't maintain tension in the higher (smaller) gears, too short and the rear mech can get dragged into the cassette (which gets expensive).

aserota

Thanks for all the help!

I'll definitely pickup a narrow wide chainring to start along with a chain catcher (just in case). The alignment looks ok along with chain length too; but I'll drop on a new chain and double check alignment when i do the fitting.

I've had the bike for a few years but it's been ridden sporadically (under 1k miles in total). It's always dropped the chain at times but at present it's dropping a lot more so needs some work

The Rookie

As the chain wears it gets less stiff in the sideways direction, that increases the chance of dropping the chain.