I've got myself some Promax brake levers which push the outer rather than pull the inner. I have not fitted the calipers yet, as i'm still waiting for them to arrive, but in the mean time i cannot get my head around how the rear brake will work.
The rear brake cable outer goes from the lever to a cable stop at the front of the top tube, then inner cable on its own to another cable stop at the rear of the top tube, then outer to the rear caliper.
Surely if the lever is pushing the outer, and the inner does not move, the brake wont work as the outer is just being pushed against the first cable stop??
The end if the inner wire is fixed on a non-moving part of the brake lever (farther up on the next set of levers, or just with the stop on your cross lever), while the moving part of the lever pushes the cable housing, thus having the same effect as any other lever, effectively pulling the wire through the cable. It's the same thing if the pull happens by pulling the wire or pushing the housing.
If you're still unclear on it, try using a brake lever that isn't attached to the handlebar. It works just as well, aside from not having good leverage, due to the design of the lever. But allowing it to float in space will show you that it doesn't matter which part of the brake lever actually moves, so long as the inner wire is pulled through the housing.
Kilo TT, Felt z85, Kona Unit 2-9, 90s Schwinn 9.3 with Noleen fork
^^^since the inner cable length is set and not pulled/shortened by the lever, the lever has no choice but to try to move the housing. the housing does not compress, but it does deflect sideways, which has the effect of pulling the inner cable with it -- the inner cable can either bust out of the housing (not happening) or pull on its ends to follow the new, longer route. It cannot pull on the lever end (fixed to an immovable lever) but can pull on the caliper, and does, to follow the longer curve. does that make sense?