HACK-Tiagra 10 speed with GRX 11 speed clutch derailleur.
Why Bicycles Stack Exchange recommends it
Bicycles Stack Exchange users cite it as real-world evidence that Tiagra 4700 10-speed shifters can drive a GRX 11-speed derailleur when working out cable pull and compatibility.
Recommended by 0 people across 0 different months, 2020 to 2020.
What it is
A short demonstration by the Moz on Bikes channel of pairing Shimano Tiagra 10-speed shifters and a 10-speed cassette with a Shimano GRX 11-speed clutch rear derailleur. It shows that the mix of parts shifts acceptably despite the nominal speed mismatch.
What people said
Cites sdgfsdh · 2020-05 · Bicycles Stack Exchange · on “What is the cable pull of Tiagra 4700 10 speed? What is the actuation ratio?”
According to this YouTube video [this video] , you can combine: Shimano Tiagra 4700 shifters Shimano GRX 812 11 speed rear derailleur 11-34t 10 speed cassette This implies that a Tiagra 4700 rear derailleur has the same actuation ratio as Shimano 11 speed road rear derailleurs, as suggested by Argenti Apparatus [LINK] . This is a ratio of 1.4 . 3 [LINK] Plugging these numbers into the equation we get: Cable pull * Derailleur shift ratio = Cog pitch Cable pull * 1.4 = 3.95 Cable pull = 3.95 / 1.4 Cable pull ≈ 2.82 So, to answer the question: Tiagra 4700 10 speed shifters have a cable pull of 2.82 Tiagra 4700 rear derailleurs have an actuation ratio of 1.4
Cites Jim · 2020-09 · Bicycles Stack Exchange · on “I am putting drop bars on one of my MTB Shimano 10 speed 1x Deore. I am looking for a road hydro shift lever”
Thanks to everyone's great help here is the solution that seems like it would work out for me, yrmv (remember this is just a theoretical setup.) Want to stay with as much as OE as I can since just winter setup, 10sp 4700 tiagra levers (same shim 11 sp road cable pull ratios including grx so can't just use any rear derailleur even though is 10sp that gets complicated see # in references and other threads.), splice in xt calipers to the levers (same cost as going with flat mount to post mount adapters which are freakin 40 bucks each.) Use a GRX RD-RX812 11 sp max 42t rear d. Will handle =~ 46t in many setups' and as scene* seems to shift fine as a 10sp d. Why Shim does not make things compatib
Cites Jim · 2020-09 · Bicycles Stack Exchange · on “I am putting drop bars on one of my MTB Shimano 10 speed 1x Deore. I am looking for a road hydro shift lever”
Here is the build I am talking about: Also, I now i know shimano mtb 11 speed derailleurs have a different cable pull than the road 11 speed including GRX. But, if you take a xt plate and pulleys and move it to the grx rear d you even easier clear 46t. [LINK] Here is the reference for RD-RX812 GRX with Tiagra 4700 10 sp levers. * [this video]
Cites thelawnet · 2020-11 · Bicycles Stack Exchange · on “Derailleur-shifters compatibility Shimano GRX”
it certainly works 'well enough'. [this video] In theory there is about 5% difference between 11-speed road & mtb spacing (3.74mm vs 3.90mm or thereabouts), but the actual pull ratios of RDs probably varies +- a few % anyway?