[jwfoss]

Mounting your bumpers as low as possible and limited rock is an excellent way to gain traction in a pushing match, and something 558 does as well. Where we differ is that if we are designing for maximum pushing force we believe that any wheel that touches the ground should be a traction wheel. Understand that any wheel that is in contact with the ground is providing traction, and increasing the number of contact points with the ground reduces the normal force on each wheel. Typically 558 will design an 8wd with a larger center to center distance between the middle wheels to increase scrub and make the robot both more stable at speed, and more resistant to spinning.

In basic terms, an 8wd robot with drop center will provide more pushing force than an 8wd with omnis on the outside all other things equal.