pic: 499 Prototype drivetrain final layout

[Ben Piecuch]

Madison,

I like the design you have presented here, with it's effective use of extruded aluminum rails. However, as a pretty experienced user of 8020, I'll make several comments:

1) The 1010 material you are using is actually fairly flexy in torsion. Add that to the bending stiffness and your deflections start to add up. With a cantilevered setup like this, those middle wheels may induce enough flex in the rail to either throw a chain (#25) or negate any drop you had to begin with. Anything you can do to add a x-plate or similar will stiffen up that center axle tremendously.

2) The 8020 fasteners are very prone to coming loose. Locktite does work, but there aren't many threads in those types of slide-in fasteners. I would make sure that you have access to the outer bearing block screws either through the spokes of your wheels or with a quick removal of the wheel.

3) There is quick a bit of "slop" in the fit of those slide-in / drop-in fasteners. You can easily get +/- 1/16" loss of accuracy in the placement of those blocks. If you machine a flat recess into the plates, you can ensure the proper alignment based on the fitment of the plates, and not the mounting holes and hardware. (though I see this doesn't work with your existing bearing placement...)

Best of luck with this design. I like seeing more and more teams come up with innovative ways to work with this material. If only 8020 ponied up and became a bigger sponsor and/or supplier for the KOP.

Bengineer