Driveline windup is also known as "axle binding" or "driveline binding". Mechanical components in the

drivetrain A drivetrain (also frequently spelled as drive train or sometimes drive-train) is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components o ...

of vehicles may bind and wear, which may occur when tires of varying sizes are used on one vehicle. It is a particular issue in 4WD cars with tires having varied tread patterns or brands. Despite marked size, different brands often differ in actual size. Even if both front and rear are the same brand, and marked with the same size they may still differ in actual size. A pull to the right or left when driving or braking could trigger windup caused by mismatched tire tread/sizes.

H-drive

Heavy off-road vehicles using 6×6 or

8×8 Eight-wheel drive, often notated as 8WD or 8×8, is a drivetrain configuration that allows all eight wheels of an eight-wheeled vehicle to be drive wheels (that is, to receive power from the engine) simultaneously. Unlike four-wheel drive drivetr ...

may use a

H-drive An H-drive drivetrain is a system used for heavy off-road vehicles with Six-wheel drive, 6×6 or Eight-wheel drive, 8×8 drive to supply power to each wheel station. H-drives do not use axles but rather individual wheel stations, usually carried ...

drivetrain. These are particularly prone to driveline windup. H-drives do not use axles but rather individual wheel stations, carried on a punt or

backbone chassis Backbone tube chassis is a type of automobile construction chassis that is similar to the body-on-frame design. Instead of a two-dimensional ladder-type structure, it consists of a strong tubular backbone (usually rectangular in cross section) ...

. A single differential splits the drive into separate left and right drive shafts, which each run fore and aft inside the bottom corners of the chassis. At each wheel station a bevel box drives the half shaft out to the wheel. Unlike a typical

transfer box A transfer case is a part of the drivetrain of four-wheel-drive, all-wheel-drive, and other multiple powered axle vehicles. The transfer case transfers power from the transmission to the front and rear axles by means of drive shafts. It also ...

for

permanent four-wheel drive Four-wheel drive, also called 4×4 ("four by four") or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case ...

, there is no differential action front-to-back. When used for equally spaced wheels (i.e. rather than cargo trucks with close-set rear axles) the front two wheels are arranged so that both steer, the rear less so than the leading wheel. The varying track radii mean that when the vehicle drives in a curve on firm tarmac each wheel travels a different distance. Without differential action between the wheels on each side, wind-up can occur in the bevels and shafts. This system and its drawbacks are probably best known through the

Alvis Alvis may refer to: *Alvis Car and Engineering Company, British luxury car and military vehicle manufacturer which later became Alvis plc * Alvis plc (formerly United Scientific Holdings plc), a defence contractor which acquired Alvis Cars and bec ...

FV600 chassis, the Stalwart and family. As well as the bevel boxes in the hull, these used an epicyclic hub gear. Standard operating instructions recommend that after travelling some miles on firm ground, the vehicle should be bounced over a curb or railway sleeper to lift wheels clear of the ground, one-by-one, to allow them to spring back and release the windup. Excess windup could easily lead to a broken gear in the bevel or hub gearboxes. To indicate this, white lines were painted across the ends of the hubs. Normally the lines should be parallel but as windup occurred they would become misaligned, indicating the need to release this.

References

{{Reflist Automotive transmission technologies