Shimano has just unveiled Tiagra-level hydraulic disc brakes (called BR-RS405 brakes) for the first time, extending its hydro braking further down the lineup and making it more accessible than ever before.
You now get to choose between four Shimano road disc brake models: Ultegra-level and 105-level hydraulic disc brakes, these new Tiagra-level hydraulic disc brakes, plus the Sora-level mechanical disc brakes that were launched a few weeks ago.
Tiagra sits below Ultegra and 105 and above Sora in the Shimano road groupset hierarchy.
The BR-RS405 has a flat-mount calliper and a mechanical hydraulic shifting lever (ST-RS405), meaning that the shifting is mechanical (as opposed to electronic which is only available for the road in the Dura-Ace and Ultegra groupsets so far) and the braking is hydraulic.
The lever shape looks very much like that of the existing 11-speed 105 hydraulic lever, although the BR-RS405 lever is 10-speed rather than 11-speed. Tiagra is currently Shimano's only 10-speed road system.
The SM-RT81-S/SS rotors are available in 140mm and 160mm diameters and feature Shimano’s existing Ice Technology that’s designed to dissipate heat and provide more braking power.
“Shifting through Tiagra’s 10 gears with the combined gear and brake unit is ergonomically pleasing for multiple hand sizes thanks to the smooth surface of the hood and the enclosed mechanism within,” says Shimano.
“VIVID Index Shifting on the 10-speed shifting system equates to a light shifting effort with a defined click engagement, so you always know you’re in the right gear. Furthermore, the reach of the lever can be adjusted by up to 10mm, providing added comfort.”
The BR-RS405 brakes use the same set up and maintenance procedures as Shimano’s other hydraulic brakes.
Shimano’s BR-RS405 hydraulic road disc brakes will be available from July. The price has yet to be set.
For reference, a pair of Shimano 105-level ST-RS505 STI levers with RS505 callipers has an RRP of £399.99 (although you can find them cheaper), so you can expect an RS405 setup to be cheaper than that.
This chart shows a comparison of Shimano’s road disc brake systems:
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now pushing 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.