Shimano GRX800 wide derailleur with 11-51 11 speed cassette?

[guidodg]

Will a Shimano GRX800 wide derailleur work with an 11 speed 11-51  cassette?

My friend currently has an 11-42 cassette on his Cannondale Topstone with a 40T but he needs easier gearing...so can I fit a larger cassette using his existing derailleur?

Obviously the chain will be too short.

Any advice on which 11 speed cassette?

Thanks in advance!

 

 

[splat]

He may be able to get an 11-46 to work
It may be OK, but a Wolf Tooth Roadlink DM would make it work better.

I am not sure (and I stand to be corrected) if that 11spd Shimano rear mech will stretch to a 51 cassette.
The new 1x12 long cage one is meant for that.

But search the interwebs, there are lots of people who have tried lots of combos and some of them work well.

[guidodg]

thanks @splat ....

I did think the GRX800 wide derailleur was supposed to work with bigger cassettes too but maybe I was wrong..

[ChrisF]

Interesting topic.

 

The much older XT derailleur certainly works well with an 11-50 Sunrace cassette.

 

Really would have expected the newer generation, long cage, derailleurs to manage this.

[splat]

3 hours ago, guidodg said:

thanks @splat ....

I did think the GRX800 wide derailleur was supposed to work with bigger cassettes too but maybe I was wrong..

Shimano was very conservative on their 11spd range

 

I am running the 2x11 (RX-810) with the WolfTooth link and a 40T cassette with no issues.

There are guys with the WolfTooth link running a 11-50 Sunrace cassette (1x11).
And then Gabaruk has some conversion kits 
 

 

Edited December 17, 2023 by splat

[guidodg]

can I rather then get the Deore M5100 1x11 MTB derailleur which is only about R500?

will it work with the GRX lever?

Edited December 17, 2023 by guidodg

[splat]

57 minutes ago, guidodg said:

can I rather then get the Deore M5100 1x11 MTB derailleur which is only about R500?

will it work with the GRX lever?

It seems that you would need a gadget to convert the pull ratio of the roadie style shifter to an MTB rear mech.

https://www.wolftoothcomponents.com/collections/drivetrain-1/products/tanpan?variant=18367738757

[guidodg]

thanks guys for all the help...

so it may be worth trying to see if it works with the existing GRX800 derailleur and then take it from there...

[christovdw]

Well, for what it’s worth…

I’m using a rapide hanger extender to fit a 11-46T 10spd cassette with my GRX RD-RX400 rear derrailleur (34T max) and it works smoothly. 🤘

[guidodg]

Thank you all for the replies.... which Shimano derailleur will work with a GRX800 gravel lever and a 11-51 cassette without any aftermarket parts?

 

[splat]

1 hour ago, guidodg said:

Thank you all for the replies.... which Shimano derailleur will work with a GRX800 gravel lever and a 11-51 cassette without any aftermarket parts?

 

I don't think that any of the 11 speed stuff will work without some modification or additional gadget.
As stated in this thread, their range is quite limited.

The new 12 speed stuff is designed specifically for the 11-51 MTB cassette
RD-RX822-SGS Long Cage

https://bike.shimano.com/en-EU/product/component/grx-12-speed/RD-RX822-SGS.html

[guidodg]

ok, cheapest and easiest is a 38T with an 11-46....