These custom made wheels and treads fit directly onto 3mm shaft gearmotors..
Each purchase gets a set of 4 wheels and two treads.
Wheels are .96" in diameter and .8" wide
Wheels with tread are 1.175" tall and 5" long.
Treads are .765" wide and require the wheels to be 3.815" apart (on center).
Wheels weigh .09oz, treads are .5oz, complete set is 4.6oz.