4720 Tiagra hydraulic levers have the same cable pull ratio as current Dura-Ace, Ultegra and 105

[Oski1997]

I have a question about the new Tiagra 4720 groupset. The 4720s use the BR-4700 calipers which use the same Shimano brake pad (L04C) and hose kit (SM-BH90-JK-SSR) used by the current 105 R7020, Ultegra R8020, and Dura-Ace 9120 groupset. Additionally, the 4720 hydraulic levers use the same cable pull ratios as the current Dura-Ace/Ultegra/105s.

Can someone confirm that what this means is that current users of the 4720 Tiagra groupset can “unofficially” use the Dura Ace (R9120), Ultegra (R8020) and 105 (R7000) front and rear derailleurs with the new hydraulic levers. THANK YOU for your time.

PS - I just noticed that the current 105, Ultegra, and Dura-Ace use the OT900 cable for the rear derailleur outer casing. The 4720 Tiagra uses the OT-SP41 for both the LEVER SIDE and the REAR DERAILLEUR side. Dura-Ace 9000, Ultegra 6800 and 105 5800 used to use the SP41 for both the LEVER and DERAILLEUR sides. But they were upgraded recently in the R7000 and R8000 series to be like the R9100 Dura-Ace. Does anyone know if this affects compatibility? Or is the new OT-RS900 just a better quality (ie uses polymer grease) cable compared to the OT-SP41 which uses the OPTISLICK grease?

Shifting lever_Shifting lever outer casing_Lever side	OT-SP41
Shifting lever_Shifting lever outer casing_Rear derailleur side	OT-RS900