rear mech woes

dvntie

So last night I decided to fit the rear mech I got on here.
So I set the limits and adjusted the third screw to take my 11-28 cassette.
The problem I'm having now is when I shift it up to the 23 25 or 28 sprocket while in the big ring, the chain is coming off the bottom jockey wheel on the mech. It doesn't happen when in the small ring tho.
I'm wondering if it's a chain tension thing and I need to add a few more links?
Any help would appreciated

Seweryn

dvntie wrote: »

So last night I decided to fit the rear mech I got on here.
So I set the limits and adjusted the third screw to take my 11-28 cassette.
The problem I'm having now is when I shift it up to the 23 25 or 28 sprocket while in the big ring, the chain is coming off the bottom jockey wheel on the mech. It doesn't happen when in the small ring tho.
I'm wondering if it's a chain tension thing and I need to add a few more links?
Any help would appreciated

Firstly, why would you shift to the cog 1-3 when you are on the big ring? That is something to be avoided and unnecessary. For lower gears that's what the small chainring is for.

But what do you mean by chain coming off the bottom jockey wheel? I have never experienced this.

Is your chain not worn out and has the properly adjusted length?

dvntie

Seweryn wrote: »

Firstly, why would you shift to the cog 1-3 when you are on the big ring? That is something to be avoided and unnecessary. For lower gears that's what the small chainring is for.

But what do you mean by chain coming off the bottom jockey wheel? I have never experienced this.

Is your chain not worn out and has the properly adjusted length?

Generally I tend not to but chain is new as is the cassette.
I think the cage lengths between the old and new mechs are different too. From the pic below it looks like the chain is under pressure alright but I have spare links

bcmf

from that picture your chain is too short to be runnng that gear combo.

dvntie

bcmf wrote: »

from that picture your chain is too short to be runnng that gear combo.

That's what I was thinking alright
I had on a rival mech abd changes to force it looks like the force cage is 1 cm longer. I'll add 1 link and see how that goes
Cheers

dvntie

bcmf wrote: »

from that picture your chain is too short to be runnng that gear combo.

Two links added and problem solved. Got me round the midleton 200 audax today.
I love it when a plan comes together

bcmf

your welcome