Can you fit a Shimano Ultegra R8000 11 Speed Rear Derailleur Medium Cage To a ten speed cassette ?

Aaron.L

New Member
Hi I am trying to fit a Ultegra medium cage rear mech to a 32-12 10 speed cassette the gears either jump or do not select properly.
I have tried the b screw on multiple different settings and always get the same result.
I have changed the gear cable and that has made little difference.
It is a new chain and cassette
Help please !!
 

monkers

I'm still watching you ...
Welcome Aaron.

Shimano 10 speed cassettes require the correct thickness spacer used on the freehub. If this is omitted then shift problems persist and the cassette will be felt to have 'float'. Otherwise there could be compatability issues between components (shifter, derailleur, cassette). You can check this by looking on the relevant Shimano page. This link may help ...

https://productinfo.shimano.com/#/com?q=ST-4700&cid=C-453&acid=C-454

I hope you get this sorted.
 

Gunk

Veteran
Location
Oxford
Hi I am trying to fit a Ultegra medium cage rear mech to a 32-12 10 speed cassette the gears either jump or do not select properly.
I have tried the b screw on multiple different settings and always get the same result.
I have changed the gear cable and that has made little difference.
It is a new chain and cassette
Help please !!
The indexing is different for 11 speed than 10. The spacers are narrower between the cogs so that’s why it’s not engaging properly.

I’ve mixed groupsets quite a bit with differing results, sometimes it just doesn’t work. A correct used 10 speed mech will only be about £30 that would be the easiest solution
 
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Gunk

Veteran
Location
Oxford
A J Tec Shiftmate will probably get it working, but it’s about the same price as a decent used derailleur
 
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Aaron.L

New Member
Welcome Aaron.

Shimano 10 speed cassettes require the correct thickness spacer used on the freehub. If this is omitted then shift problems persist and the cassette will be felt to have 'float'. Otherwise there could be compatability issues between components (shifter, derailleur, cassette). You can check this by looking on the relevant Shimano page. This link may help ...

https://productinfo.shimano.com/#/com?q=ST-4700&cid=C-453&acid=C-454

I hope you get this sorted.
Thanks for your reply
I have used Shimano 1.8 mm spacer and all the parts are compatible as the rear mech does what the shifters tell it.
Do you think it is possible the shifters may be broken ?
 
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Aaron.L

New Member
The indexing is different for 11 speed than 10. The spacers are narrower between the cogs so that’s why it’s not engaging properly.

I’ve mixed groupsets quite a bit with differing results, sometimes it just doesn’t work. A correct used 10 speed mech will only be about £30 that would be the easiest solution
Thanks for the reply however I have tried a ten speed rear mech and the problem still persists.
 

Gunk

Veteran
Location
Oxford
Sounds like it is shifter problem, start by pulling on the cable hard and shifting down just to make sure all the cable is released from the shifting mechanism
 
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monkers

I'm still watching you ...
Thanks for your reply
I have used Shimano 1.8 mm spacer and all the parts are compatible as the rear mech does what the shifters tell it.
Do you think it is possible the shifters may be broken ?
Hi Aaron

You haven't said if you have followed the link to the compatibility chart that I provided. I don't know what shifter (10 or 11 speed?) you are using, so it's not possible for me to suggest a way forward.

The 8000 Ultegra derailleur is 11 speed. As others have said the pull ratios between 10 and 11 speed set ups are different. This derailleur is not compatible with any Shimano 10 speed cassette AFIK.

If the shifter is 11 speed, then an 11 speed cassette will be needed with no spacer. If the shifter is 10 speed, then either a 105 or Ultegra or Dura ace 10 speed derailleur will be needed. The Tiagra 10 speed set up is different again - so no compatibility to what you already have from that series to consider.

I'd say your best bet is to follow the official Shimano compatibility chart and make a recommended combination accordingly.

Good luck.
 

si_c

Veteran
Location
Wirral
Thanks for the reply however the derailleurs do what the shifters tell them so i do not think this issue is the problem.
Sort of, the levers pull a certain amount of cable which causes the derailleur to move a certain amount across the cassette. The different speed derailleurs move different distances for the same amount of cable pull.

This means for a 10 speed derailleur 1mm of cable might move it 2mm and for 11 speed only 1.5mm for example.
 

Gunk

Veteran
Location
Oxford
Thanks for the reply however the derailleurs do what the shifters tell them so i do not think this issue is the problem.
It's actually the opposite, the rear mech has no indexing function, it moves freely, the indexing is created by the shifters. So if you use a 11 speed shifter with a 10 speed mech and cassette the chain will not quite be in the correct place.

I recently had a set up with 9 speed Sora shifters, 9 Speed Sora rear mech but with a Campag Chorus Cassette. A Shiftmate changed the indexing slightly between the shifters and rear mech so the chain was in the correct position. The rear mech was unmodified as the indexing is controlled by the shifter and Shiftmate.
 

si_c

Veteran
Location
Wirral
Hi all I have ordered some new 10 speed shifters to replace my old ten speed shifters, the should be coming on Monday (gmt) i will let you know how it goes.
for those questioning the pull ratios this article may explain what I am trying to say.

https://bike.bikegremlin.com/1278/bicycle-rear-derailleur-compatibility/

The parts on the bike are:
tigra 4700 10 speed levers
ultegra 8000 gs rear mech
10 speed shimano casstee and chain
Which shifters did you get?

Keep in mind that Shimano 11 speed road components will not work with 10 speed components.
 
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