omg hills

[nicholas]

Cheers for the answer its things like this i feel i need to know

 

[Nigelnaturist]

it can't be done under pressure - you have to back off first.

Did it today, changed from the middle to the outer whilst climbing a short climb without putting to much strain on the components and it was happy enough to change with no untoward noises.
Eased of a little in terms of pressure but kept the rotation of the chain rings going eased the lever across and up went the chain.