Chain drop when back pedalling

[worriesnot]

Desperately need some expert hub-help on a Friday night....

Just installed an extended 11-42 cassette by replacing a std 11-36 10 speed cassette.

Chainrings in the front are 24 & 38.

Also installed a longer b-screw.

When in the 24 on the front and 42 at the back everything looks aligned fine and the mech picks up the chain nicely into the 42 sprocket.

Here comes the problem;

when I back pedal the chain drops two sprockets...

When in the second biggest sprocket in the back - which on this cassette is a 36 - and back pedals, the chain also drops to the third biggest sprocket.

When in the third biggest sprocket, all is fine and the chain does not drop when back pedalling.

 

I did not change anything on the mech. Also did not change the chain.

 

Apart from the obvious "do not pedal backwards" solution  - what else is there to do? or what could be causing this?

[Johnny Lawless]

Desperately need some expert hub-help on a Friday night....

Just installed an extended 11-42 cassette by replacing a std 11-36 10 speed cassette.

Chainrings in the front are 24 & 38.

Also installed a longer b-screw.

When in the 24 on the front and 42 at the back everything looks aligned fine and the mech picks up the chain nicely into the 42 sprocket.

Here comes the problem;

when I back pedal the chain drops two sprockets...

When in the second biggest sprocket in the back - which on this cassette is a 36 - and back pedals, the chain also drops to the third biggest sprocket.

When in the third biggest sprocket, all is fine and the chain does not drop when back pedalling.

 

I did not change anything on the mech. Also did not change the chain.

 

Apart from the obvious "do not pedal backwards" solution  - what else is there to do? or what could be causing this?

 

Not much you can do about that infortunately. Very common 1x problem, I have the same on mine. 

 

 

Chain line plays a part here:

 

https://www.oneupcomponents.com/pages/understanding-chainline-for-optimal-1x-conversions-boost-and-non-boost

[SwissVan]

As long as i recall its always done that on all my bikes...

Question is why pedal backwards?

 

Of course i found this out by accident  

[Thor Buttox]

Desperately need some expert hub-help on a Friday night....

Just installed an extended 11-42 cassette by replacing a std 11-36 10 speed cassette.

Chainrings in the front are 24 & 38.

Also installed a longer b-screw.

When in the 24 on the front and 42 at the back everything looks aligned fine and the mech picks up the chain nicely into the 42 sprocket.

Here comes the problem;

when I back pedal the chain drops two sprockets...

When in the second biggest sprocket in the back - which on this cassette is a 36 - and back pedals, the chain also drops to the third biggest sprocket.

When in the third biggest sprocket, all is fine and the chain does not drop when back pedalling.

 

I did not change anything on the mech. Also did not change the chain.

 

Apart from the obvious "do not pedal backwards" solution - what else is there to do? or what could be causing this?

My 1x11 has been doing the same thing. I took it in and I watched my mech use a 'hangar adjustment tool' to show me that my hangar was way out of straight even though it looked in alignment. Anyway, it fixed the issue pronto. The tool is a thing you screw into the wheel axle and it goes around touching the wheel rim (or not, if it is skew) like a big math's compass. Being slightly out of alignment but not out of position laterally was dropping the chain.

 

My 2c.

[HTFU]

If your chain is worn or "stretched" then as you backpeddle it won't mesh nicely with the new sprocket teeth causing the dropping. Pedaling forward under load will force the teeth and chain to mesh but back pedaling there is no tension in the chain to force an unevenly worn chain and sprocket to mesh. Try and stick a new chain on. Dropping when back pedaling is a known issue with Shimano 11-42 cassettes.

[Pulse]

As stated bu Swiss and Pyka...

Its a very common problem with 11/12 systems. Pedaling forwards the derailure will keep the chain aligned (obviously), but when backpedalibg there is nothing to keep it there, and it will default to closer to the chainline.

Crank spacers may make it 'better', but typically only shifts the 'problem' up or down.

 

I'd say just live with it

[worriesnot]

Thanks all!

It's still a 2x10 by the way - just changed the cassette from 11-36 to 11-42...

 

Went for a long Breedtsnek ride today. Everything fine. Chain still drops when back-pedalling, but not a problem as I don't back pedal when using the specific "problem" gears.

 

As ya'll says: I'll just live with it.

[BaGearA]

Thanks all!

It's still a 2x10 by the way - just changed the cassette from 11-36 to 11-42...

 

Went for a long Breedtsnek ride today. Everything fine. Chain still drops when back-pedalling, but not a problem as I don't back pedal when using the specific "problem" gears.

 

As ya'll says: I'll just live with it.

I think it has something to do with wide range cassettes and the mech's they're paired up with.

 

 

As mentioned many 1x11 have this problem but many also don't ( my NX does not).

 

 

Maybe it could be down to the more B-tension I don't know.

 

 

As for back pedaling there is not much reason to just do it , BUT you do it quite a lot without noticing it like getting your favourite pedal at 3 oclock  or getting your strong foot forward for rythem section.

 

Its just a tiny back pedal you don't realise you're doing

[Johnny Lawless]

Thanks all!

It's still a 2x10 by the way - just changed the cassette from 11-36 to 11-42...

 

Went for a long Breedtsnek ride today. Everything fine. Chain still drops when back-pedalling, but not a problem as I don't back pedal when using the specific "problem" gears.

 

As ya'll says: I'll just live with it.

In that case look at whether there is a crank spacer on the driveside. You can move it over to the non-driveside to see if that improves the chainline.