[Boltman]

Its fairly simple to determine what size bumpers you need.... use walls and string

Place your robot against wall (without bumpers) that defines a side THEN for each side at least 8 in. of BUMPER must be placed on each side of each outside corner. IF a side is less than 8" entire side must be covered.

So for a U shaped bot the front side would require 8" bumpers per front corner. Thats assuming traditional U-shape with two front corners.

For odd shapes... or to verify corners

Simply wrap a string around the bot (in bumper zone)..any corner of that string shape (frame perimeter) needs an 8" bumper per outside corner side. So its hard to get around 8" rule even with very unique shapes. Either each comer needs 8" bumper side or the entire side <8" needs a bumper, your choice. Anything inside the frame perimeter shape does not need a bumper.

Your extension zone is now 15" beyond original frame perimeter with same shape.