Chain coming off chainring

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onmyback

Active Member
My chain has been coming off the inside of my Q45 chainring, in the lowest couple of gears. I can't see that the angle of the chain is any more than on an 11 speed diamond frame bike, so I'm unclear why this is happening. Is it happening to anyone else?
A friend has suggested fitting a front derauler, but I'm hoping not to need to purchase one just to use as a chain keeper.
IMG_2640.JPG
 
DavidCH

DavidCH

In thought; expanding the paradigm of traversity
It happened to me many times. Eventually as your chain is older it lengthens. Every ride I used to go out with my QXL rings I would have the chain come off at least twice in 40kms. Not much fun if your going down a hill on a vendetta. I recently adjusted the oval chainring and tightened the chain and adjusted the spring tensioner on the rear deurallier... my last ride the chain didn't come off in 50km so I am well pleased. You can now get qxc chainrings from rotor that have the tooth fittings to hold the chain on the ring.
 
O

onmyback

Active Member
DavidCH said:
It happened to me many times. Eventually as your chain is older it lengthens. Every ride I used to go out with my QXL rings I would have the chain come off at least twice in 40kms. Not much fun if your going down a hill on a vendetta. I recently adjusted the oval chainring and tightened the chain and adjusted the spring tensioner on the rear deurallier... my last ride the chain didn't come off in 50km so I am well pleased. You can now get qxc chainrings from rotor that have the tooth fittings to hold the chain on the ring.
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My Q45 is only a few months old and has been ridden about 1500km. On my other bikes, I usually get over 2 years use from a chain, but I'll check it with my chain wear tool.
 
paco1961

paco1961

Zen MBB Master
For any 1x set up I always use a narrow/wide front ring such as made by Absolute Black, Wolf Tooth or even the Sram cx1. The chain sits deeper and more snug without increasing trag. In addition I find it tough to keep a 1x chain in place without using a rear Derailleur (sorry I know it’s FD on a CB. Force of habit) with a clutch mech as found in most mtb mechs. If you are on any amount of rough road or hit a set of RR tracks at 25 or 30 mph it is hard for the chain to stay in place. I have used the Sram cx1 front ring and RD with great success. So, narrow/wide front ring and anti-slap, clutch style RD. Should take care of it. If you have a Shimano style RD you can open up the guts and switch the spring tension from default to the higher tension position to stop some of the chain jump.
 
ReklinedRider

ReklinedRider

Zen MBB Master
paco1961 said:
So, narrow/wide front ring and anti-slap, clutch style RD. Should take care of it.
Click to expand...

Agreed. I have been running SRAM 1x11 on my Vendetta with no problem. I use the Apex 1x11 road RD; has the clutch, and built in barrel adjuster. Works very well. Also use the wide/narrow chainring.
 
B

Bill K

Guru
I had a similar problem for a while on the S40. I had too many spacers on the drive side of the BB (initially set up for a Rohloff hub then switched to 1x11).
The square taper bottom bracket in your picture above looks pretty wide (based on looking at the left crank arm).
It looks like you can loosen the chainstay bolts and slide the BB shell to the left about 2mm or so to improve the chain line.
Might be worth trying that.
 
O

onmyback

Active Member
The chain only measured about 25% worn, but it was getting dry. I oiled it and it hasn't jumped off since. If it happens again, I'll try moving the BB shell to the left. Hopefully I don't need to start replacing OEM parts that have almost no wear.
 
burando

burando

Member
Since I spend all of my time in on the small sprockets, my LBS adjusted the derailleur tension to stop chain pop.
 
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