Derailleur cage lengths

[antnee]

On looking through the posts r.e Derailleur Cage lengths I am now at a loss! 1) are short, medium and long cage lengths all set to standard lengths. and 2) do different manufacturers short, medium and long cages vary from one another? As I have a Shimano tiagra RD ( not sure of the model number) but the cage pulley wheel centres are 75 mm apart and can only run 30-11 cassette on it and on my other bike have a Shimano Ultegra GS ( which I was told was a medium length cage and the cage pulley centres are just 10 mm longer at 85 mm and can run a 32-11
I will add that the Chain stay lengths are the same at 410 mm.
I have ordered a shimano Sora R 3000 medium cage can any one tell me what the pulley wheel centres are for this Model of Shimano RD? as it would save me trying it out I realise I will need to fit new chain with a couple of more links to allow for larger cassette.
Many thank for any Ideas

 

[classic33]

Shimano have three codes for rear derailleur length:

Short - SS Medium - GS Long - SGS

Not aware of where this is printed on the RD though.

 

[antnee]

Thanks for that reply I did know that the SS was the code for short cage and GS- Medium but was unaware of SGS for the Long cage But What I really wanted to know is the pulley wheel centre distances for all three different cages! Thanks would but really helpful if I know these measurements

 

[the snail]

http://productinfo.shimano.com/#/spec/2.6/ROAD/Rear Derailleur?q=rd-r3000
up to 34T cassette, don't know what the cage length is though.

 

[antnee]

Hello Snail Thanks for that Spec chart l got carried away with all that information on it I wouldn't have known where to start looking for that information , pity its got everything one needs to know about all the part numbers and what it relates to except cage lengths! Thanks for that anyway will definitely save that in my bookmarks for future reference

 

[Ajax Bay]

Spec chart [has] got everything one needs to know . . . except cage lengths

That's because you don't need to know cage lengths: you need to know the spec of what the different cages can wrap (eg chainring difference plus large/small sprocket difference) - its capacity. You can then try to exceed that parameter by trial, until the RD doesn't wrap the chain (or don't have the chain long enough to go large/large and be (very) careful).

 

[presta]

As Ajax says, all you need to know is the total capacity, max front difference, and the min/max sprocket size. See here.

 

[antnee]

Thanks both of you but lets just say for curiosity sake to satisfy me , as I'm now genned up thanks to you all on the codes and cassette capacity there is nowhere that tells me the SS, GS or LGS lengths As I have three different bikes one with a Tiagra and I don't know what mark it is but it has cage pulley centres at 75 mm and another bike with Ultegra GS RD : cage length centres 85 mm and an Alivio SGS RD M340 at cage centres 80 mm I'm now thinking that I have all three types Perhaps?

 

[presta]

My RD-M530 has 100mm pulley centres, and a total capacity of 45T, max sprocket of 34T*, and max chainring difference of 22T. When I buy new components I always copy the specification off the Shimano website before they go obsolete.

(*Edited after Ajax pointed out error)

 

[Ajax Bay]

RD-M530 has 100mm pulley centres, and a total capacity of 45T, max sprocket of 22T, and max chainring difference of 22T.

Max sprocket = 34t. Lucky you have copied (?) the spec before it goes obsolete.

1) are short, medium and long cage lengths all set to standard lengths. and 2) do different manufacturers short, medium and long cages vary from one another?

1) No 2) Yes
Campagnolo Nuovo Record Pat '76: cage length centre to centre = 47mm. Capacity about 30t (nominally 26t) if that helps.

 

[the snail]

mm I'm now thinking that I have all three types Perhaps?

The model code is usually stamped on the back of the mech. Cage length determines the capacity of the mech, but the largest sprocket size depends on the geometry of the mech.

 

[presta]

Max sprocket = 34t. Lucky you have copied (?) the spec before it goes obsolete.

How did I manage that, I can't even copy off a sheet of paper without a typo.

 

[antnee]

OK thanks Ajax. I did wonder about manufacturers differences , And thank You Snail for where to look for RD model no,
And thanks to you presta for that info r.e the size of your rear mech 100 mm is certainly a big gap though if your max is 45 teeth on the lowest sprocket its no wonder, this has given me something to go on I suppose a professional bike engineer would know all this without even thinking about it

 

[Ajax Bay]

presta for that info r.e the size of your rear mech 100 mm is certainly a big gap though if your max is 45 teeth on the lowest sprocket its no wonder, this has given me something to go on

@presta 's RD is RD-M530 has 100mm pulley centres, and a total capacity of 45T, max sprocket of 22T, and max chainring difference of 34T. [Edit:max sprocket of 34T, and max chainring difference of 22T - see post below]. Capacity (see post #6 above) of 45t; not largest sprocket. It's an MTB RD so it needs to cope with a triple chainring difference of (say) 22t and a small-large sprocket difference of (say) 23t (eg 11-34 cassette).

 

[presta]

@presta 's RD is RD-M530 has 100mm pulley centres, and a total capacity of 45T, max sprocket of 22T, and max chainring difference of 34T. Capacity (see post #6 above) of 45t; not largest sprocket.

No, you had it right when you corrected me the first time. Just for the record, this is the correct info:

RD-M530:
45T Total capacity
34T Max sprocket
22T Chainring difference

(My gears are 22-32-44 and 11-34, so chainring diff = 44-22 = 22, sprocket diff = 34-11 = 23, and total capacity = 22+23 = 45)