Dropping chain

[RobertWhitehead]

15 minutes ago, ChrisF said:

 

Why ?

 

I have two bikes with 1x11 and 36 rings.  No drops in 8 000 km.

 

One has a chain guide.  No guide on the other

Are you running a 11/46T at the back? What I have found is: if you increase the size of the ring to 36T or even bigger and run a 46T at the back, once the chain goes into the 46 at the back it loads the spring in the rear mech to such an extent that the moment you shift (release the tension in the spring) it pulls the chain off the front. 

[madmarc]

You need to provide more info

What group set you running ? SRAM or SHITMANO

Chainring size and is it a standard or Narrow wide - Is it round or oval chainring ?

Chainring mounted position relative to chain angle when in your climbing gear. 

Does the RD have a clutch ?

Is the chain length sized correctly ?

 

[Steady Spin]

Does the chain drop to the inside or outside of the chainring? 

My money is on the chain line being off.

[ChrisF]

5 hours ago, RobertWhitehead said:

Are you running a 11/46T at the back? What I have found is: if you increase the size of the ring to 36T or even bigger and run a 46T at the back, once the chain goes into the 46 at the back it loads the spring in the rear mech to such an extent that the moment you shift (release the tension in the spring) it pulls the chain off the front. 

 

Thanks

 

The Giant had 11-46 on.  Chain length was set maximum, to not "stretch" the derailure.  Also, it has the chain guide on.  When I replaced the cassette I could only get 11-42 at the time ....

 

Also 11-42 on the other bike.

[dasilvarsa]

Change the Chain and Chainring Together

[MORNE]

Edit: dbl post

Edited August 10, 2022 by MORNE

[MORNE]

1 hour ago, ChrisF said:

 

Thanks

 

The Giant had 11-46 on.  Chain length was set maximum, to not "stretch" the derailure.  Also, it has the chain guide on.  When I replaced the cassette I could only get 11-42 at the time ....

 

Also 11-42 on the other bike.

 

7 hours ago, RobertWhitehead said:

Are you running a 11/46T at the back? What I have found is: if you increase the size of the ring to 36T or even bigger and run a 46T at the back, once the chain goes into the 46 at the back it loads the spring in the rear mech to such an extent that the moment you shift (release the tension in the spring) it pulls the chain off the front. 

For what it's worth...i run 42T/11-42 on my bike and have 40T/11-46 on my wife's bike, and don't have these issues on either. Granted they are gravel bikes....but surely a groupset doesn't know what it is bolted to lol. 

Edited August 10, 2022 by MORNE

[madmarc]

1 hour ago, ChrisF said:

 

Thanks

 

The Giant had 11-46 on.  Chain length was set maximum, to not "stretch" the derailure.  Also, it has the chain guide on.  When I replaced the cassette I could only get 11-42 at the time ....

 

Also 11-42 on the other bike.

Going from 46 - 42 = a shorter chain by at least 1 full link

[RobertWhitehead]

7 minutes ago, MORNE said:

 

For what it's worth...i run 42T/11-42 on my bike and have 40T/11-46 on my wife's bike, and don't have these issues on either. Granted they are gravel bikes....but surely a groupset doesn't know what it is bolted to lol. 

Is it a MTB rear mech? And how many links does your chain have? If lets say you use a 36T in the front with with a 11/46T in the back and you use a standard length chain: +/-118 links then the rear mech will pull the chain off the front ring when in the lightest gear. If you adjusted the limit screw and added 2 links to your chain then you will not have any issues. Or this has been my experience with it 😁

[MORNE]

3 minutes ago, RobertWhitehead said:

Is it a MTB rear mech? And how many links does your chain have? If lets say you use a 36T in the front with with a 11/46T in the back and you use a standard length chain: +/-118 links then the rear mech will pull the chain off the front ring when in the lightest gear. If you adjusted the limit screw and added 2 links to your chain then you will not have any issues. Or this has been my experience with it 😁

i use GRX 812 on mine...she has XT 11 speed on hers. And Yes, you are right...I use 12 speed chains that are 126 links on both these 11 spd setups. "normal" 11 spd chains are too short. 

[DieselnDust]

<awaits pictures with baited breath>

[MORNE]

22 minutes ago, DieselnDust said:

<awaits pictures with baited breath>

leftfield theory based on past events...

spez epoxied BB oval'd and 1* Toe-in/out is JUST enough to drop chain

 

 

 

ignore me OP. just being silly

😊

 

[ChrisF]

1 hour ago, MORNE said:

 

For what it's worth...i run 42T/11-42 on my bike and have 40T/11-46 on my wife's bike, and don't have these issues on either. Granted they are gravel bikes....but surely a groupset doesn't know what it is bolted to lol. 

 

I really needed a 40 ring on Saturday ....

 

Riding with a roady from Franschhoek with a strong wind from behind .... with a 36 and 11 I was spinning like crazy 😵‍💫

[ChrisF]

1 hour ago, madmarc said:

Going from 46 - 42 = a shorter chain by at least 1 full link

LBS replaced both cassette and chain. 

[Andrew Buckley]

If it is a narrow wide chainwheel, is the chain on the correct sprockets?  I.e. big gap on a wide sprocket, small gap on a narrow sprocket.

Is the derailleur shimano?   If so is the clutch closed?

[DieselnDust]

So many questions 

nooo pitchas