Short, medium or long cage rear derailleurs ?

[Jameshow]

If 25t cassette then a short cage will give you the slickest change.

Why??

I would think it depends on the RD, cassette, cables and shifters rather than length of cage??

 

[Ajax Bay]

It is an old Campagnolo cassette and the big ring has 25 teeth. And on the chainring the teeth are 48 , 39, 30 also old Campagnolo

A short cage will easily cope with the wrap needed ((13+18=31) and capacity 30 nominal (and always stretchable).
@Jameshow Ceteris paribus.

 

[boydj]

I think a short-cage derailleur would not have the capacity to deal with a triple crankset. Double, fine, but a triple needs more capacity.

 

[Alex321]

I think a short-cage derailleur would not have the capacity to deal with a triple crankset. Double, fine, but a triple needs more capacity.

His triple only has a spread two more than the most common double around at the moment 48-30 as opposed to 50-34, so I wouldn't have thought that likely to be an issue, with his cassette only going up to 25.

 

[woodbutchmaster]

I think a short-cage derailleur would not have the capacity to deal with a triple crankset. Double, fine, but a triple needs more capacity.

In the end l fitted a medium cage and it works just fine !