Quote:
Originally Posted by synth_floyd
Anyone ever heard of someone doing a DIY assisted pull up machine?
A frictionless rope is great in theory (I have a degree in mechanical engineering and in school we did lots of problems with "frictionless" ropes because they simplified the problem down to the basics), but in reality ropes over bars aren't smooth. They stick, then move. They slide around too, as there's no pulley to guide them. The weights will probably hit you (or at least contact you) on the way up and down. And, rubbing a rope against a bar like that will result in wear pretty quickly.
You may be able to overcome these difficulties and get something to work, but why reinvent the wheel? Just use a band. Sure, they provide more assistance at the bottom than the top, but you're just using it until you're stronger. And, it's easier to carry a band to the park than it is to carry a rope and counterweights.