I’ve read my newish ultegra is a 10spd system based on 11spd technology and spacing. If I go 1x do I need an 11spd cassette? I was thinking of putting a sunrace dinner plate on the back.

I’ve read my newish ultegra is a 10spd system based on 11spd technology and spacing.

It’s not. There have been 2 11spd Ultegra groupsets (6800 and R8000) released since the last 10 speed Ultegra (6700)

You need an 8,9 or 10 speed road (anything except Tiagra 4700) or 8 or 9 speed mtb rear mech and a 10 speed cassette.

Just checked, it’s 4700 tiagra :oops:.
Is this the same pull ratio as ultegra 10spd? Im not drop bar knowledgeable, obviously.

Just checked, it’s 4700 tiagra :oops:.

That is based on the 11speed road mech pull ratio (but qith 10 clicks), but still uses normal 10speed cassettes and spacing.

4700 is the awkward child in the line up. It will only work with 4700 10speed rear mechs or 11speed Road mechs, but not old 8/9/10speed road or 8/9speed MTB, or 10/11speed MTB mechs.

You might be able to get somewhere using a 4700 or 11speed road mech rated for 32/34t cassettes, and then add a goatlink or similar to extend the capacity. I’ve not personally tried it but I recon you might be able to get to 40 possibly 42t that way, ‘the internet’ suggests it’s a goer…

Ok, cheers.

as amedias says many things you can do with other shimano road shifters you can’t do with a 4700 – i bought a pair having read the great reviews but failed to spot the pull issue – officially limited to 34 max rear – so might push to 36 if you accept the general wisdom that shimano understates capacity

http://bike.shimano.com/content/sac-bike/en/home/components11/road/Tiagra4700/rd-4700-gs.html

and pretty sure whatever you put on the back will have to be a 10speed cassette to match your 10 clicks on the front shifter

edit as said goatlink or similar to get past 34 max issue

So, if 4700 rear mech has X tooth capacity when used with 2x, would that capacity not be increased if going 1x?

nope

capacity and max-sprocket are two different things.

capacity relates to how much chain length/variation it can take up and is (mostly) a function of cage length. For example with 3x by you’ve got more chain slack to take up between granny and big than you do on 2x, hence triple mechs being longer. You also need a longer cage to accommodate massive cassettes but most current mechs can cope with a fairly wide range, especially in 1x setup <– this is generally pretty spot on in Shimano specs but can be influenced by things like chainstay length so there is some leeway built in

max-sprocket is determined by the location of the top jockey and whether it will clear the diameter of the sprocket. <– this is normally pretty conservative* in Shimano specs, ie: a mech rated to 32t will normally clear 34t, and on some frames will do 36t. (Goatlink extends this by moving the mech further way from sprockets)

* In some cases massively so, I’ve managed to use Ultegra 6600 mechs officially only rated to 27/28t with 34t cassettes and a bit more B-screw wound on with no issues an acceptable shifting. Problem is you won’t know for sure until you try!

I haven’t tried it, but everything I’ve read/seen points to the 4700 GS rear mech working just fine with an 11-36T rear cassette.

e.g.

[video]https://www.youtube.com/watch?v=4s_N9CUGXAw[/video]

I have 4700 on one of my bikes, and when the time comes (it’s about to get its 3rd new chain), I’m going to try a 12-36 cassette.