A pallet jack includes a forked frame and a jacking cylinder, and is supported at least in part by left and right steering wheels. A drive wheel may be located between the left and right steering wheels, with a center of each of the steering wheels and a center of the drive wheel located in a co-planar orientation. A motor provides power to the drive wheel.

A wheel assembly for a material handling vehicle includes a chassis, a first caster wheel mounted to the chassis, a second caster wheel mounted to the chassis, a torsion bar coupling the first caster wheel to the second caster wheel, and a constant force mechanism coupled to at least one of the first caster wheel, the second caster wheel and the torsion bar. The first and second caster wheels are displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force opposing a displacement in the at least one dimension.