Wheelbase

In both road and rail vehicles, the wheelbase is the horizontal distance between the centers of the front and rear wheels.

[1] The wheelbase of a vehicle equals the distance between its front and rear wheels.

So, for example, when a truck is loaded, its center of gravity shifts rearward and the force on the rear tires increases.

If the vehicle is accelerating or decelerating, extra torque is placed on the rear or front tire respectively.

The equation relating the wheelbase, height above the ground of the CM, and the force on each pair of tires becomes: where

So, as is common experience, when the vehicle accelerates, the rear usually sinks and the front rises depending on the suspension.

Thus, in a car with a short wheelbase ("SWB"), the short lever arm from the CM to the rear wheel will result in a greater lateral force on the rear tire which means greater acceleration and less time for the driver to adjust and prevent a spin out or worse.

Wheelbases provide the basis for one of the most common vehicle size class systems.

Prime Minister of the United Kingdom Tony Blair was given a long-wheelbase version of the Rover 75 for official use.

[3] and even some SUVs like the VW Tiguan and Jeep Wrangler are available with long wheelbases.

In contrast, coupé varieties of some vehicles such as the Honda Accord are usually built on shorter wheelbases than the sedans they are derived from.

The wheelbase on many commercially available bicycles and motorcycles is so short, relative to the height of their centers of mass, that they are able to perform stoppies and wheelies.

In skateboarding the word 'wheelbase' is used for the distance between the two inner pairs of mounting holes on the deck.

A reason for this alternative use is that decks are sold with prefabricated holes, but usually without trucks and wheels.

It is therefore easier to use the prefabricated holes for measuring and describing this characteristic of the deck.

A common misconception is that the choice of wheelbase is influenced by the height of the skateboarder.

However, the length of the deck would then be a better candidate, because the wheelbase affects characteristics useful in different speeds or terrains regardless of the height of the skateboarder.

For example, a deck with a long wheelbase, say 22 inches (55.9 cm), will respond slowly to turns, which is often desirable in high speeds.

A deck with a short wheelbase, say 14 inches (35.6 cm), will respond quickly to turns, which is often desirable when skating backyard pools or other terrains requiring quick or intense turns.

On some larger wheelbase locomotives, inner wheels may lack flanges in order to pass curves.

As railway lines are designed to take a predetermined maximum load per unit of length (tonnes per meter, or pounds per foot), the rail vehicles' wheelbase is designed according to their intended gross weight.