They designed a rear suspension system that stays beneath the bed floor, and still gives 18-inches of wheel travel. They did it using a cantilever system much like the F1 guys did.

A cantilever-style suspension is the plush-riding, space-saving answer. 0:00 / 0:00. By introducing a pivot point (or points, though a single pivot tends to be simpler and move more freely) ...

They designed a rear suspension system that stays beneath the bed floor, and still gives 18-inches of wheel travel. They did it using a cantilever system much like the F1 guys did.