Dual Lever setup on Magura hydarulic rim brakes
I just got a pair of HS66 hydraulic brake levers and plan on running the calipers from the HS11 set. I would like to know whether it would be possible to run the HS11 levers together with the HS66. This should be equivalent to running two HS11 levers on one HS11 caliper. This setup is intended for a cyclocross bike. Thanks!
I got this answer from a user in the forum magura has on their site :
actually, I suppose Martin means to replace the HS33 levers by HS66/HS77 ones rather than add them to the system, not too sure though. Obviously this is possible.
As these rim brakes are closed systems (other than the disc brakes which are open systems), theoretically it should be possible to link several masters to one pair of slaves, just as it would be possible to link several slaves to one master (though in that case you'd obviously end up with half the brakeforce per pair of slaves). Just make sure that you'll only use one pad wear adjuster (TPA for the HS33 lever, I don't know what it looks like for the HS66/HS77 lever) to compensate for pad wear. Otherwise you'd be able to drive the pads way too much into the rim surface!
Another thing not to try is to actuate both masters simultaneously as you'll move the slave pistons to much as well. I don't suppose you'll manage with the number of hands you have available but it could occur in a crash or so.
The way to make this work would be to mount the levers in series. As the HS33 one would probably be the inboard one so attach the bleed hole of the HS33 to the HS66 lever use the bleed hole of the HS66 for bleeding. The tricky bit here would be to have the hose attachment at the proper angle for bleeding whilst at the same time have the hose in a continuous upward orientation. Otherwise you'd trap air in some local peak in the hose routing. You might have to remove the HS66 lever from the brake and mount it somewhere else for the bleeding process. Something you'll have to figure out for yourself.
Another practical issue that crosses my mind is how you think you'd be able to slide a pair of HS33 levers on a drop bar. The lever doesn't have a split clamp so it will probably get stuck somewhere halfway the roller coaster.
Ok, here comes the disclaimer. There as quite a few things that could (not should) go wrong. You see, you can't really go wrong with the regular Magura rim brakes. If you set them up properly, they'll work fine for a long time. With this "two masters in series" setup, you could actually mess up in the operations phase. Beware bleeding will be a bit more tricky as well. This as well as the fact that Magura probably hasn't tested this kind of setup (after all this is just theoretical reasoning, I have never built a Frankenstein like this myself) could be reason that Magura doesn't cover this under their warranty. And no one can guarantee nothing other than what's described above could go wrong.
Anyway, like I mentioned above. First check whether the HS33 lever fits your handlebar. If it doesn't, you wouldn't have to bother with all the rest either .