Some notes on Binky that might help...

-She only has 73mm wheels and she is still quick enough to land heavy hits when she needs to.

-The wheels are just behind the weapon axle. Means the steering is easy and predictable.

-The chassis flexes by the 4mm ground clearance letting the machine bottom out in a hit. Once that happens all force is transferred to the opponent.

Also...

-Your design lends itself to an exo-skeleton design with thicker armour to make its structure stiff. try using thinner walls with aluminium blocks bolted to them to support your weapon shaft.

-Inertia XL had its wheels so far back that it would pitch up almost onto its side in a hard turn, waggling its other wheel in the air. Try and keep the distance as short as you reasonably can to prevent the robot lifting itself to far up.