We have a 26" wheel tandem (Trek T900) with linear pull brakes that we've gradually changed to more of a road bike style - narrower slick tires, road bike handlebars, bar end shifters and brake levers intended for linear pull brakes.
The rear braking is adequate - I can lock the wheel - but just barely - it is quite mushy. I'm very experienced riding and know how to use the front and rear brakes, and am perfectly comfortable using the front brake first and most often, and doing it correctly. So, overall braking is adequate.
I'm pretty experienced at cabling and think I do a decent job in minimizing excess housing, making the runs as efficient as possible, etc. For what it's worth, the rear derailleur, in spite of the long run, works pretty darn well. Front shifting and braking is solid.
But on this bike, of course, the rear brake cable is really, really long. There are unavoidable loops, and when I hit the brakes on the work stands (I use two stands to work on the tandem!), I can see fairly significant movement in the cable housings in a couple of places where it loops. The biggest culprit is a loop it makes from near the rear seat tube around to the brake. The other is in the front where the housing goes from the handlebars down to the top tube where it heads back to the rear. I believe it's this flopping around that causes a lot of the mushy-ness. I've never seen this sort of flopping around on the road or mountain bikes I've cabled.
I've got the pads adjusted to the rims as close as practical. Even with the brakes adjusted like this, I have to take the lever to the bar to get good braking. Again, like I mentioned, the levers are the tektro ones intended for linear pull brakes. The front brake feels as tight and solid as my road bike brake.
So, I'm just looking for some hints as to ways I can mitigate this issue, aside from buying a new tandem with hydrolic dics in back!