Saddle tank The fuel tank on
a truck or tractor.
Semi-trailer Truck trailer supported at the rear by
its own wheels and at the front by a fifth wheel mounted to a tractor or dolly.
Setback Axle Front steering axle moved rearward
from the generally accepted standard position. Advantages: Shorter turning
radius and more of a vehicle's weight shifted to front axle.
Shipping Weight "Dry" weight of a truck including
all standard equipment, but excluding fuel and coolant.
Single-Source Leasing Service in which companies
can lease drivers and trucks from the same source, rather than having to procure
them from different companies.
Sleeper Sleeping compartment mounted behind a truck
cab, sometimes attached to the cab or even designed to be an integral part of
Sliding Fifth Wheel Fifth wheel mounted to a
mechanism that allows it to be moved back and forth for the purpose of adjusting
the distribution of weight on the tractor's axles. Also provides the capability
to vary vehicle combination lengths.
Sliding Tandem (Slider) Mechanism that allows a
tandem axle suspension to be moved back and forth at the rear of a semi-trailer,
for the purpose of adjusting the distribution of weight between the axles and
Space Cushion An area around a vehicle which would
allow a driver time to avoid an accident.
Speedability Top speed a vehicle can attain as
determined by engine power, engine governed speed, gross weight, driveline
efficiency, air resistance, grade and load..
Spread Axle (Spread Tandem) Tandem axle assembly
spaced further apart than the standard spacing of 54 inches. The U.S. federal
bridge formula favors trailer axles with an eight or nine foot spread by
allowing higher weight than on tandems with standard spacing.
Spotter A terminal yard driver who parks vehicles
brought in by regular drivers. It I is also a supervisor who watches the
activities of the driver on the road.
Synchronized Transmission Transmission with
built-in mechanisms to automatically "equalize" the speed of its gears to allow
smooth shifting without the need to double clutch.