Bumper Bars for Wheelie Bars This is an aluminum bumper bar (includes two pieces) for our wheelie bars. Bolts in at rear with bolt to hold the wheelie wheels on and buyer has to install an additional bolt to keep bumper bar rigid. (Bumper bars are good protection from the sled climbing up on rear of tractor (required in some clubs) and to use as a push bar to push tractor around with a four wheeler.) Bumpers are 6” high and designed to work with 6” diameter wheelie wheels. Two styles available.