Bumper to back of cab is a critical dimension in heavy truck chassis design and fleet purchasing. It determines how much frame space is left for the payload body or fifth wheel while remaining within legal overall length limits. A shorter measurement allows for a longer trailer, which is why cab-over-engine designs were historically popular before length laws were relaxed.
Heard on the job
We need a day cab with a 112-inch BBC to make sure the dump body fits without extending the wheelbase.