long / short / medium derailleur cage??

ILIKEFOOD

Ho Folks,

so my dad destroyed his 105 5800 11 speed gsl (long cage) derailleur on his brand new bike. He slipped on road gritting and bent the hangar, he then proceeded to cycle, shift gears, snap the hangar and bend the cage to a point beyond repair.

So my question to you is can he go for a medium cage derailleur.

Crankset & sprocket cassette is :

Crankset: Cp Shimano 105 Kfc5800cx04l 50 -34 170mm (Xs, S) /

172.5mm (M) / 175mm (L, Xl)

Sprocket/Casette: Cp Shimano 105 Kcs580011132 11-speed 11-32t

And looking at this to replace

http://www.chainreactioncycles.com/ie/en/shimano-105-5800-11-speed-rear-mech-medium-cage/rp-prod116506

105 5800 11 speed medium

Compatible with 11-speed drivetrains
Maximum low sprocket 28-32T with double chainset
Maximum front difference 16T, total capacity 37T

We calculated his drivetrain size as 37

Thanks for your help!

cython

ILIKEFOOD wrote: »

Ho Folks,

so my dad destroyed his 105 5800 11 speed gsl (long cage) derailleur on his brand new bike. He slipped on road gritting and bent the hangar, he then proceeded to cycle, shift gears, snap the hangar and bend the cage to a point beyond repair.

So my question to you is can he go for a medium cage derailleur.

Crankset & sprocket cassette is :

Crankset: Cp Shimano 105 Kfc5800cx04l 50 -34 170mm (Xs, S) /

172.5mm (M) / 175mm (L, Xl)

Sprocket/Casette: Cp Shimano 105 Kcs580011132 11-speed 11-32t

And looking at this to replace

http://www.chainreactioncycles.com/ie/en/shimano-105-5800-11-speed-rear-mech-medium-cage/rp-prod116506

105 5800 11 speed medium

Compatible with 11-speed drivetrains
Maximum low sprocket 28-32T with double chainset
Maximum front difference 16T, total capacity 37T

We calculated his drivetrain size as 37

Thanks for your help!

That one looks like it should be fine, as it takes up 37 teeth in slack/capacity, and your dad's gearing has just that (50+32 = 82, 34+11 = 45, 82-45 = 37). In actuality, as far as I can make out there are only 2 lengths of rear mech in 105 5800 anyway, GS and SS (http://bike.shimano.com/content/sac-bike/en/home/road/shifting---braking/rear-deraileurs/rd-5800-gs-l.html is a link to GS but has GS-L in the URL), so medium is long basically, with 4 teeth difference (conveniently that same difference as between the 28t and 32t rear sprocket )

diarmaidol

in case you needed further confirmation ;-) My bike is compact 50/34 same cassette and came originally with the RD-5800-GS Rear Derailleur.

smacl

Also using a medium cage on 50/34 and 11/32, I think the long cage is really only needed for triples and MTBs with very wide ranges.

ILIKEFOOD

thanks for everyone's input. It looks like as cython pointed out that there is only short and long in the 5800 range. Was a bit confused by CRC referring to it as medium, but I saw that it is indeed 'long' as confirmed by one of their staff in the Q&A section

cython

ILIKEFOOD wrote: »

thanks for everyone's input. It looks like as cython pointed out that there is only short and long in the 5800 range. Was a bit confused by CRC referring to it as medium, but I saw that it is indeed 'long' as confirmed by one of their staff in the Q&A section

I think as another poster pointed out, they're medium cage compared to some of the MTB options available, e.g. 40+ tooth capacity on http://bike.shimano.com/content/sac-bike/en/home/mtb1/shifting---braking/rear-derailleur/rd-m9000-sgs.html

Alek

The other night I have successfully installed 11-34 cassette on the better half's bike running 50/34 double and a 3500 Sora short cage mech....:-)

robyntmorton

Alek wrote: »

The other night I have successfully installed 11-34 cassette on the better half's bike running 50/34 double and a 3500 Sora short cage mech....:-)

That's interesting. My bike is 3500 Sora, with an 11-28, and came with the longer GS cage. When I was enquiring about going 11-32 in my LBS, they demanded that it be on a long cage. Good to know if I ever need to swap more parts that the SS cage can do it.

cython

Alek wrote: »

The other night I have successfully installed 11-34 cassette on the better half's bike running 50/34 double and a 3500 Sora short cage mech....:-)

robyntmorton wrote: »

That's interesting. My bike is 3500 Sora, with an 11-28, and came with the longer GS cage. When I was enquiring about going 11-32 in my LBS, they demanded that it be on a long cage. Good to know if I ever need to swap more parts that the SS cage can do it.

:pac::pac:

doozerie

Alek wrote: »

The other night I have successfully installed 11-34 cassette on the better half's bike running 50/34 double and a 3500 Sora short cage mech....:-)

You may be aware of this already, but it's likely that some gear combinations will no longer "work" with that mix. Upper and lower ends of the range should be fine, but there may be combinations in the middle where that short cage is unable to take up the excess chain slack, making those combinations essentially unusable.

Similarly, you can exceed the recommended limits of probably any rear mech, to an extent, with the same compromise. As an example, I have a Campag Chorus groupset dating from 1999, its spec states a max of 26 on the rear with 39 on the front. By adding an extra couple of links to the chain it handles 39/28 with no problem (no issues changing in or out of the gear, no issues while in the gear), but you then can't use 39/14, and possibly not 39/15 either I can't quite remember. Having the lower gear was handy but I got fed up of having to avoid those mid gears as they fall within the range I like to use a lot.

Alek

Tested the whole range, everything works well. Small ring / large cog gives a little different sound but works correctly even under load.

I don't get why gears in the middle would be affected while ends of the range are fine?

Alek

Tested the whole range, everything works well. Small ring / large cog gives a little different sound but works correctly even under load.

I don't get why gears in the middle would be affected while ends of the range are fine?

(edit)

I get it now. In fairness I haven't tested small/small, and I understand now that chain slack may occur, but realistically this combination is most unlikely to be used :-)

I'll keep this in mind and test later. BTW this bike came with 11-32 and small Sora mech from the manufacturer...

cython

Alek wrote: »

Tested the whole range, everything works well. Small ring / large cog gives a little different sound but works correctly even under load.

I don't get why gears in the middle would be affected while ends of the range are fine?

I think the reason for concern over the middle of the range is that 50x11 (61t) and 34x34 (68t) don't have that much of a difference in the slack left between them, but 34x11 (45t) is in the middle of the range (albeit not an ideal combo), and could leave enough slack that the mech might not take it up.

Alek

Curiosity prevailed:

50 / 34:



34 / 11:



They are not ideal, but work ok.

cython

Alek wrote: »

Curiosity prevailed:

50 / 34:



34 / 11:



They are not ideal, but work ok.

I've seen worse on the small/small combo, but the derailleur looks pretty strained on the 50/34 combo! That said you might have capacity to take up an extra link in small/small, which would alleviate said strain a bit.

EDIT: Are you sure that's a short cage mech? The ratio of cage length compared to the mech body looks more like GS from the Shimano site than it does SS (in that it looks like the lower jockey spindle would sit further to the rear than the limit screws when collapsed, and SS doesn't look like that would happen

Alek

but the derailleur looks pretty strained on the 50/34 combo!

I run similar configuration on my 1x10 setup for more than a year, no problems so far.

Are you sure that's a short cage mech?

I am 90% sure. Haven't checked the stamp/label on the mech itself...

robyntmorton

I've never seen my GS mech in that position in 34/11, so I'd be calling it as an SS one.

Unknown Soldier

cython wrote: »

I've seen worse on the small/small combo, but the derailleur looks pretty strained on the 50/34 combo!

Provided there is still an "S" rather than going straight through, it's still good to go.

Plus you would only be in that gear combo by accident, which does happen!

The main issue is Clearing the cogs, using the "B" screw, or so I thought.

[edit] That looks like a GS (medium) RD too btw.

Alek

You were right guys. The cage is 74mm c/c and Sheldon Brown says it's Gs (medium). Note that SS is still rated to 32t by Shimano though!

doozerie

Alek wrote: »

I get it now. In fairness I haven't tested small/small, and I understand now that chain slack may occur, but realistically this combination is most unlikely to be used :-)

In my case of the Campag groupset with the 28t rear cog, the issue didn't arise in smal/small - I wouldn't us that combination anyway as I don't like to crosschain.

The cassette I used was a 13-38, with 39/53 up front. I couldn't even use the 14-39 combo due to the slack in the chain. I could possibly have installed a half-link and that might have allowed 14-39 to work while also accommodating 28-39 but I never bothered. It was easier in the end to revert back to a 12-26 cassette and a shorter chain.

Russman

Apologies for reviving an old thread, but my question is very similar (and quite possibly covered in the earlier posts but the techie jargon is a bit confusing for me !)

Anyway, I'm running a compact 50/34 with an 11-28 cassette. Its 105 (pretty sure its 5700) from 2011. I'm just wondering if I would be able to fit a 12-30 cassette without any hassle or without changing any other parts ie RD etc. ?

Thanks !

NeedMoreGears

I've run 12-30 on 50/34 with a short cage 105-5700. It worked fine. I may have adjusted the b-nut on the derailleur itself but I didn't change anything else, because the original cassette was an 11-28

The derailleur died after a few years and I replaced it with a medium cage 5700 so that I could get a 32 on the back. I replaced the chain with a chain two links longer in that case. I figured 1 link for the longer derailleur and 1 link for the extra teeth on the cassette (effectively 2 teeth bigger as the chain on sits on half the cassette). It works fine also