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I am putting a bike together using GRX 400 10 speed and the rear mech feels so cheap and plastic, I just don’t trust it. My question is, can I install a GRX 810 rear mech instead as, although 11 speed, it had the same cable pull ratio?
This will tell you all
You can use a 4700 Tiagra rear mech. Largest cog size is 34. No clutch on the Tiagra. https://bike.shimano.com/en-EU/product/component/tiagra-4700/RD-4700-GS.html
"Compatible with current 10s road DUAL CONTROL LEVER" https://bike.shimano.com/en-EU/product/component/grx-10-speed/RD-RX400.html
So you can mix and match between Tiagra 4700 and GRX 400.
I'm a bit disappointed to hear that the GRX is a bit plasticy. I was thinking of swapping the Tiagra for the GRX 400 has it has a clutch.
Are Shimano MTB Mechs compatible?
Could you use an SLX 11 speed Mech and Cassette and the GRX shifters?
I'm sure the mech will be fine, but if you really want to change you could look at the Wolf Tooth Tanpan, it should let you run an MTB mech (note, I've not tested it!).
Thank's for that. The Tanpan is a good option.
Why don't you just build it with 11 speed?
Linusr: Here is a link showing the plastic component: https://imgur.com/kESU5hw It's probably okay, but as an integral part of the mechanism I don't trust it. Especially as I ride throughout the year off-road on the moors in the dark with no phone signal. One of the limit screws has already made a dent in it and I haven't even touched it. My choice is to run with it and hope for the best or find a better solution.
"Are Shimano MTB Mechs compatible?
Could you use an SLX 11 speed Mech and Cassette and the GRX shifters?"
No, MTB mechs are not compatible with road shifters from 10 speed onward. Different cable pull ratio. MTB cassettes can be used with road rear mechs, within limits (up to +4 teeth more than stated max. teeth number)
@Colin74 thanks for the photo of the plastic bit on the mech. I share your concerns about plastic.
MTB 11 speed mechs are not compatible with road/gravel shifters. But it appears that 11 speed road mechs will work with road/gravel 10 speed shifters. This video uses Tiagra 10 speed with a road 11 speed mech.
No idea if the road mechs used feature plastic bits, tho 😉
@linusr Thanks for the video! He also has it working with GRX 812 so it will definitely work. I ordered the new rear mech earlier anyway in the hope it will be okay and it certainly will, so thanks again 😁👍
No, MTB mechs are not compatible with road shifters from 10 speed onward.
Thanks, thought that the case, what a pain in the arse. SLX 11sp mechs are available so much cheaper.
So I’m too late to try and sell you 1 month old Ultegra R8000 Long cage derailleur then? Poo.
Good luck 👍
@linusr I will definitely report back. Thanks for your help.
@linusr A report back, of sorts. I have seen the GRX810 rear mech up close now and it has the exact same plastic component as the GRX400! I am surprised as I have never seen this before, I guess Shimano know what they are doing and it must be strong enough. I will stick with the 400 and see how it goes.
@colin74 that's interesting. I wonder if the RX Ultegra - can't remember exact model number, but it has the same faux MTB look about it and I think large cog capacity. I've always managed to bash my rear mechs and bend the hangers on my bikes. I seem to have a habit of only falling on the right side.
@linusr Just had a look at some images online and yes it does use the same part. That's an expensive way you have of falling, I suppose the right side is better than the wrong side! I usually just go over the handlebars.
@Colin74 I go over the handlebars, too. But I always land on my right side. And always on my hip - which has two titanium pins in it from a, erm... previous fall on my right side. At least the pins aren't plastic, otherwise I'd worry...