The track width is useful, but may not give the actual axle width. The wheels used do not always have the same back space as front space. This applies to most older rear wheel drive cars and light duty trucks as the wheels are close to having their center sections at the center of the wheel. This may not apply to a later model vehicle. Take a late model Chevy 1/2 ton truck for instance. These wheels have much greater back space than a comparable 1/2 ton of 30 years ago.
