A configuration where all four wheels are powered is shown in Fig. 6.18. A single pump provides flow to four motors. This machine can be built with two or four steerable wheels.
On three-wheel- and four-wheel-drive vehicles, the front wheels are configured to have a tangential velocity slightly higher (1 or 2%) than the rear wheels. This improves steering and helps to improve tractive effort. A large-capacity pump is required to operate all of these motors connected in parallel.
