Well, I bought a bike called "Iron Horse" and the bike has front and rear mechanical disc brakes. The brakes, upon inspection, have no writing at all (The manufacturer was too scared to put their brand name on them...).
Since day one, they have been absolutely terrible; Back brake only locks the wheel when I let weight off and the front brake would sooner have me hit a car in front than actually do any noticeable braking. I'm aiming to be able to lock the front brake to the point that pulling the lever makes me flip the bike like on my road bike, and the back brake cause wheel lock-up with merely about 30% action.
Cabling routing and length seems fine to me, brake lever is not bending, nor is mount for it. Caliper mount is nice and sturdy and does not move no matter how much I clamp on the brake. The pads are not half-inserted, nor are they worn out. They're brand new! Pads are not contaminated, pads are equal distances from the rotor on either side of the caliper, cable is tensioned so that the brake is pulled 15% of it's total action before pads contact the rim. The rotor is arrow-straight. The wheel hub where the disc attaches is not damaged in any way nor weakened considerably.
I've never worked on disc brake bikes, so my question is; Do all mechanical disc brakes have this much difficulty stopping? Is there something big that I'm missing? Is there a particular thing causing this? Could the pads be a bit duffed? Is there any type of pad I should try out on my bike (different compound, etc) or any specific modifications I should try?
And finally, are there any really, really risky bodges that I can try out to immediately bolster braking power? (Anything I do on the bike is not your fault, but my own.) Give me a really risky method of making the brakes powerful instantly and I'll give it a shot! :P