I'm currently building up a gravel bike from a 90s Cannondale F600 and it only has rim brake tabs. I would really like to use hydraulic rim brakes on it and so am wondering if anyone has tried this combination?
I know both use mineral oil and have the same inner and outer hose diameters so in terms of plumbing it together, I'd just need to use the correct olives and barbs at each end.
My only concern is that the GRX levers may have a different master cylinder size to the original Magura levers and what that would do to braking performance and lever feel?
Has anyone tried this before or is more knowledgeable on the inner workings of hydraulic brakes to tell if it would work, Thanks.
by Kind_Mycologist_7989
6 Comments
I asked the same q on Reddit ages ago, there’s one model of Magura drop levers that is unobtainable for mere mortals, no one reported any experiments with different make levers, I hope someone in this thread has experimented fingers crossed
They will probably not work as the Magura rim brake system is a closed system without reservoir.
A normal disc brake pulls a little bit of extra fluid every time the piston is pushed out past a certain point. This is the basis of automatic pad adjustment. Also why you need to push back the pistons when you install new pads.
The Magura rim brake does not do that. Also the cylinder sizes will be different. The rim brakes have huge amounts of pad displacement, that alone will be a showstopper.
If you really want to try it you can hack something together and test it. The chance of success is very low.
You could use the rotor groupsets as they use Magura Hardware
not possible, the magura rim brakes have massive 14-16mm master cylinders in addition to the closed loop hydraulics
I have a friend who did exactly this, it works but not that well. The grx levers push a lot less hydraulic fluid than the magura levers, as a result he had to adjust his pads to be really close to the rims to get them to work at all. When they were adjusted super close they worked okay, but it was problematic if his wheels became out of true.
On a weird alternative, you could try magura HS33 4 finger levers and surly corner bar, and a regular mtb 1×12 drivetrain.
You wont get GRX lever ergonomics, but you will get a clutched derailleur