[davidtanner]

This is a very good example of a geek's solution to the wrong problem.

The point of pullups is to improve upper body strength and muscularity. Once one is able to do 10-15 pullups in one set with bodyweight the stress of this unweighted movement is insufficient to cause much further adaptation.

At this point the trainee should start doing pullups with added weight and/or do pullups on ropes, a fat bar or a vertical pipe.

So, instead of actually making real progress in improving his grip, upper body and back strength, the OP has managed to spend a lot of money quantifying something almost worthless. That money and time could have been productively invested in buying some sand, putting it in heavy garbage bags and then loading a backpack to add weight to his pullups.

Note: For a cheap(possibly free) pullup training tool simply get a regular claw hammer, use the claw on top of the doorjam(or tree limb) and grab the handle with both hands and do pullups. Chalking your hands will almost certainly be required otherwise they will slip off.

[ScottWhigham]

I think you're missing the point. Have you met geeks before? (And I say that tongue-in-cheek!) They thrive on stuff like this. I love it! I think there are some who would say that, if you don't particularly like this type of article, that you may not really enjoy HN overall.