49 inches = Compact Bike Rack
Trucks with a width of at least 49 inches but not greater than 59 inches will fit the compact bike rack. The compact rack comes in two sizes that holds either 2 or 3 bikes.
59 inches = Full Size Bike Rack
Trucks with a width of at least 59 inches will fit the full size bike rack. The full size rack comes in 3 sizes. It holds either a 3, 4 or 5 bikes. The best part is that if you buy a 3 bike rack you can always buy extra arms later to make it a 4 or 5 bike rack.