Shimano GRX RD-RX400 RD w/ 11-42 cassette

[old fat man]

My son's road bike is 1x11 with r7000 shifter, r7000 rear derailleur and 11-40 cassette. It shifts wonderfully and would likely clear a 11-42 as well. No special road link or wolf tooth in use. It was a very inexpensive swap from the claris 2x9 that was on the bike and with a 40 tooth front ring, he still clears the junior gearing rollout.

[NHAero]

Checking in for an update.
I have an R8000 RD with a Wolftooth Roadlink on my Litespeed dropbar MTB, with an 11-40 11s cassette, RS685 11s shifters, and 42-28 front rings. It works, but it is definitely the least good shifting of all my bikes.

Which RD in the GRX or RX series would best replace the R8000 and Roadlink set-up?

[Erik_A]

All 3 would work

Originally Posted by NHAero

Checking in for an update.
I have an R8000 RD with a Wolftooth Roadlink on my Litespeed dropbar MTB, with an 11-40 11s cassette, RS685 11s shifters, and 42-28 front rings. It works, but it is definitely the least good shifting of all my bikes.

Which RD in the GRX or RX series would best replace the R8000 and Roadlink set-up?

[HTupolev]

Originally Posted by Moneywatch

Thanks for the summary. Do you think the RX400 RD will work with a Dura Ace 7800 group/shifters to allow for lower gears since the cranks are 53/39?

No. Shimano changed their 10-speed derailleurs and shifters starting with Tiagra 4700. The cassettes are compatible across old and new, but the derailleurs and shifters are not.

[molly47]

Take a look at this link I heard it works well

Garbaruk GRX cage extends Shimano gravel derailleur range, up to 50T cassettes!