Bolt pattern explained: what 6x139.7 means

How lug count, pitch circle diameter and center bore decide whether a wheel fits.

The two numbers

A bolt pattern such as 6x139.7 gives the number of wheel studs (6) and the diameter of the imaginary circle that runs through their centers, the pitch circle diameter (PCD), in millimeters (139.7 mm). The same pattern is often written in inches: 6x139.7 mm is 6x5.5".

Measuring it

Even stud count (4, 6, 8): measure center to center across two directly opposite studs.
Five studs: there is no opposite stud, so measure from the center of one stud to the far edge of a stud that isn't next to it, or use a bolt-pattern gauge.

Patterns that look close are not interchangeable. 6x135 (Ford F-150 since 2004) and 6x139.7 (Silverado, Tacoma) differ by under 5 mm, enough to stress the studs.

Center bore

The center bore is the hole in the middle of the wheel that sits over the hub. On a hub-centric wheel it matches the hub diameter, so the hub carries the load and centers the wheel. Aftermarket wheels often have a larger bore; a hub-centric ring fills the gap. A wheel whose bore is smaller than the hub will not fit.

Also check

Offset (ET, in mm) moves the wheel in or out and affects clearance to brakes, suspension and fenders.
Lug nut seat (conical, ball or flat) must match the wheel.
Thread size of the studs (for example M14x1.5) must match the lug nuts.

Look it up by vehicle

Last reviewed 2026-10-14.