Drop Center Distance

[Andrew Schreiber]

Originally Posted by Chris is me

Drop centers are a function of a few variables

1. Wheelbase length and width
2. Wheel material (rubber, tread, pneumatic, tracked)

Good rules of thumb:
Pneumatic wheel - 1/4"-3/8"
Treaded wheel - 1/8"
Rubber wheel - 3/32"

Your mileage may vary. Keep in mind all of the "conventional wisdom" for drop centers was determined when wheelbases were usually 38x28, or much longer than they are wide. Drive bases closer to square shapes may need less drop, and wide bases may need no drop at all. But a little too much on a 6WD isn't the end of the world.

This year 228 did 1/8" drop on a 10WD, with the outer wheels raised up 1". This was unnecessary, we didn't need any drop at all with how short our effective wheelbase was.

Not mentioned but also important:

Surface you're on. Carpet is gonna be different than HDPE is different than metal mesh.

Stiffness of chassis. A wet noodle of a chassis won't matter how much drop you have.

[MechEng83]

8 wheels, 8" (actually 200mm) pneumatic.
center wheels were dropped 0.5" (alternately, end wheels were raised 0.5"....)
with a center distance of 8.75" between wheels.