Shimano Rear Mech Short cage question

[RobertWhitehead]

I am sure a longer screw will create enough clearance 

[DieselnDust]

1 hour ago, The Ouzo said:

was a 5800 11spd medium cage, its been changed to a 7000 short cage

max sprocket size for that derailleur is a 30T. so thats already a problem. A longer cage will solve the problem and it will likely cost less than a goat link.

try sjscycles.co.uk as the local distributor is useless

[The Ouzo]

29 minutes ago, DieselnDust said:

max sprocket size for that derailleur is a 30T. so thats already a problem. A longer cage will solve the problem and it will likely cost less than a goat link.

try sjscycles.co.uk as the local distributor is useless

or, since I already paid the bike shop and they fitted the wrong part, they should get the correct RD for me and swap it out.

I already called them today and they seem confused that its the wrong RD (despite the invoice etc. pointing to an SS), so I think I'll take some pics tonight and visit them tomorrow. They can order the right RD and I'll bring the bike in when it arrives.

[MORNE]

I dont know…Shimano are always conservative with their gear range on rear mechs. If it says max 30T, as @RobertWhiteheadstated, winding on some b-screw will do the trick on 32T imo. Hell a GRX 11speed medium cage rear mech is listed as 42T max and it eats up 46T without effort on my bike…51T with a goatlink installed. 
 

Edit: but I agree, if you had medium, let them get a medium. You didn't ask for a hack job, doesn't matter if it might work or not. 

Edited August 15, 2023 by MORNE

[DieselnDust]

3 hours ago, MORNE said:

I dont know…Shimano are always conservative with their gear range on rear mechs. If it says max 30T, as @RobertWhiteheadstated, winding on some b-screw will do the trick on 32T imo. Hell a GRX 11speed medium cage rear mech is listed as 42T max and it eats up 46T without effort on my bike…51T with a goatlink installed. 
 

Edit: but I agree, if you had medium, let them get a medium. You didn't ask for a hack job, doesn't matter if it might work or not. 

but you have a goatlink fitted hence the derailleur has the extra capacity to "eat" the bigger sprocket. Its just when the guide pulley does try to eat the sprocket when regret sets in...

without the goatlink your derailleur will struggle with sprockets that are bigger than the design capacity

[MORNE]

7 hours ago, DieselnDust said:

but you have a goatlink fitted hence the derailleur has the extra capacity to "eat" the bigger sprocket. Its just when the guide pulley does try to eat the sprocket when regret sets in...

without the goatlink your derailleur will struggle with sprockets that are bigger than the design capacity

Not that it really matters anyway, since it’s a different mech to the one in question, but If it wasn't clear….It does 11-46 without a link. It does 11-51 with a link. There was some redundancy in my system at least that meant i worked out just fine.

same with old 11speed m8000 XT long cage mechs. Everything you read will tell you it wont do 42/11-46. Not only did it, it did it on a 105 road shifter using a wolftooth Tanpan on the stock derrailleur link😅. 

Doing what the box says is boring…live a little haha.

Edited August 16, 2023 by MORNE

[DieselnDust]

So you’re saying a road derailleur can handle a Mtb cassette?

[The Ouzo]

right so the bike shop has ordered the right part.

again it shows your experience with a place boils down to who you deal with, when I spoke to the original guy I deal with, over the phone yesterday, he was adamant that the SS would work perfectly fine, went to the shop thsi morning and spoke to someone else and he agreed is should be the GS and wnet ahead and ordered it for me.

[The Ouzo]

The bike shop finally go stock and replaced the short cage RD with a medium cage.

Some feedback.

The short cage works on the 11-32 cassette, but in the larger cogs you can feel that things are not running as smoothly as they should.  I spent some time both on the work stand and during rides fine tuning the cable tension. For the most part changes were snappy and smooth, but every now and then it would skip a gear on changes or hang onto a gear for a little to long, requiring you to add a small bit of input through the levers to change.

Also the drivetrain was rather noisy. With fresh lube it would be quiet, but 20-30km later and its noisy again.

I did 460km with the short cage.

I've only done around 55km with the medium cage, but the difference is noticeable. Drivetrain is quieter, it runs smoother through all the gears and changes so far are consistently crisp and quick.