Magura rim caliper and Shimano hydraulic road lever compatibility I have a trekking bike with a slightly short reach for me. On the other hand I wish to get a drop bar bicycle. I could check on this bike that the position is good with drop bars.
On this bike I have on front wheel a Magura MT5 disc brake, and on rear wheel a HS11 Magura rim brake, of course both hydraulic. My frame is rim brake only at rear. It used to be a 26in bike, but I could put 27,5 (584 mm) and adjust rear brake on it.
I have read that MT5 can work with Shimano road levers, but could not find information about HS11. I guess the question is on piston area.
Is it possible to make work HS11 and shimano hydraulic road lever (such as Tiagra 4700, GRX 400/600, or 106 R7000, to be defined).
Yes but not optimal/recomended.
Technically, the lever will push the caliper pistons, but Magura's disc levers, such as the MT5, push a different amount of fluid than their rim brake levers, such as HS11. And the shimano levers have a more similar push to the Magura disc levers. So it won't be optimal.
In trials riding, they say you shouldn't mix disc levers with the rim calipers as there is a large chance for the brake to fail (even if it's a momentary minimal slip) when you need them the most.
In normal, non action sport, conditions it will probably be ok. It just won't feel as good as matching the road levers to the disc caliper.
If you choose this method, (same goes for the MT5 caliper) make sure that you choose the correct fittings for each end, otherwise you risk fluid leaking and no more braking.
As a little side note, Magura did release drop levers for rim brakes called HS66.