Chain Binding on Small Ring

[tp_mantis]

So my wife and I went for our first real tandem ride which included a 1.5 mile climb. Right before the climb we get a flat... fun but no problem.

Then when I shift into the small ring the chain catches on the ring and wraps around binding causing us to come to a complete halt. We stop, i pull the chain off the ring to make sure it can move freely, give a few spins and looks good. Get on and same issue. Repeat for ten minutes then we mash our way up in the middle gear.

We made it, wife relatively happy. All things considered a good ride and i told her it has to get better. So any idea why its binding? Spins fine on the stand but issues with rider(s) on.

[oldpotatoe]

So my wife and I went for our first real tandem ride which included a 1.5 mile climb. Right before the climb we get a flat... fun but no problem.

Then when I shift into the small ring the chain catches on the ring and wraps around binding causing us to come to a complete halt. We stop, i pull the chain off the ring to make sure it can move freely, give a few spins and looks good. Get on and same issue. Repeat for ten minutes then we mash our way up in the middle gear.

We made it, wife relatively happy. All things considered a good ride and i told her it has to get better. So any idea why its binding? Spins fine on the stand but issues with rider(s) on.

Teeth 'shark toothed', holding onto the chain under load? Not allowing it to come off the bottom of the ring?

[Kontact]

For some reason I've seen this a little too often lately. Generally, it seems more likely on compact cranks, especially flexible one (like the Vumaquad) and chainrings with a large jump between them, like 50x34. Small damage like bent teeth or grooves in the shift ramps can exasperate it.

Things that seem to help:
Really low, close front derailleur mounting to the big ring with precise angle adjustment.
Stiffer front derailleurs, like Shimano's.
Stiffer chains. A SRAM solved one issue that a Shimano DA had problems with. Wipperman might be another good one to try.
Shimano rings.


This can be a real pain, so expect a little work to resolve it.

[oldpotatoe]

For some reason I've seen this a little too often lately. Generally, it seems more likely on compact cranks, especially flexible one (like the Vumaquad) and chainrings with a large jump between them, like 50x34. Small damage like bent teeth or grooves in the shift ramps can exasperate it.

Things that seem to help:
Really low, close front derailleur mounting to the big ring with precise angle adjustment.
Stiffer front derailleurs, like Shimano's.
Stiffer chains. A SRAM solved one issue that a Shimano DA had problems with. Wipperman might be another good one to try.
Shimano rings.


This can be a real pain, so expect a little work to resolve it.

Think the problem is that the chain isn't coming off the bottom of the small ring, just wrapping the chain up on the ring, not really a shifting issue..

OP yes? No?

[Kontact]

Think the problem is that the chain isn't coming off the bottom of the small ring, just wrapping the chain up on the ring, not really a shifting issue..

OP yes? No?
My take on it was that the chain was trapped between the middle and small gear, jamming it between them and causing something like chain suck. Which is a kind of shifting issue, even though the derailleur is not at fault.

[Kirk Pacenti]

Teeth 'shark toothed', holding onto the chain under load? Not allowing it to come off the bottom of the ring?

I would agree that this is typically the cause.

OP - How old are the drive-train components? May be time to replace the rings...

Cheers,

KP

[tp_mantis]

Thanks all for the Responses - hopefully i can get all your questions answered.

The chain is not falling off the ring, it is sticking and wrapping around like OldPotatoe interpreted

The age of the drive train is new for everything except the cranks - those are original with use unknown.

I will take a look when i get home to see if the small ring is sharkified or messed up in any way.

Might just have to replace the small chain ring but i will look at all the rings to see.

thanks again

[vsefiream]

Check the chain, my chain had a poor link where the master pin was sticking out and catching the big ring. The pin would catch and then wrap up.