105 Rear mech - long or med?

[DrSquirrel]

I have a 105 rear mech I need to replace RD-5600 but I have no idea if its along or medium. Only other lettering on it is FJ which does't seem to relate to the SS and GS options yo usee online (also long isn't as avalible as short/med).

I have a triple, 30 39 52 with a 12-25 cassette. From looking online it seems a medium will do - but looking at pictures it seems I might have a long cage...


How do I tell? :/

 

[Angelfishsolo]

I have a 105 rear mech I need to replace RD-5600 but I have no idea if its along or medium. Only other lettering on it is FJ which does't seem to relate to the SS and GS options yo usee online (also long isn't as avalible as short/med).

I have a triple, 30 39 52 with a 12-25 cassette. From looking online it seems a medium will do - but looking at pictures it seems I might have a long cage...


How do I tell? :/

Take a look at the second answer on this page. It will either help or confuse the hell out of you

 

[DrSquirrel]

I've already done the search, hence why I am asking here.

Doing the "calcuations" I can run a med or long apparently - but prefereablly I would like to use the same as what I have now...



If anyone knows they have a med or long, would they kindly measure between the jockey wheels?

 

[RecordAceFromNew]

How do I tell? :/

Measurements are in the first table here.

 

[DrSquirrel]

Thanks, that confirms a long cage @ 86mm - thanks.

 

[baznav]

Yes you need a long cage GS for a triple and SS for a double chainset, the difference between the small and large chain ring mean you need a longer cage on the mech to take up the slack in the chain.