The standard deck size for the Swivelwheel 58 series is 5 ft. long x 8 ft wide.
The 6" extension increases the length to 5'-6" this provides a wider loading surface for carrying Motorcycles, Golf Carts, Trikes, and Can-Am Spyders or anything with a wider foot print.
Note : All Swivelwheels are side loaders when adding the 6" extension
