Off-Road Fitment Glossary

Plain-English definitions of the terms that decide whether a wheel, tire, or lift kit will actually fit. Written for owners — no catalogue jargon, no marketing copy.

Bolt pattern
The lug count and PCD diameter that determine which wheels can physically bolt to a vehicle hub.
PCD (Pitch Circle Diameter)
The diameter of the imaginary circle that passes through the centre of every lug hole on a wheel hub.
Hub bore
The diameter of the central spigot the wheel centres on — must equal or exceed the wheel's centre bore.
Hub-centric ring
A small ring that fills the gap between an oversized wheel centre bore and a smaller hub spigot, restoring centric loading.
Wheel offset
The distance in millimetres between a wheel's mounting face and its centreline — positive tucks inboard, negative pokes outboard.
Lift height
How much a kit raises the body away from the axles, measured in inches; primarily controls tire clearance.
Bolt adapter
A machined plate that bolts to a vehicle hub and presents a different bolt pattern (and often wider track) to the wheel.
Max tire diameter
The largest tire (overall diameter, in inches) a chassis clears at full articulation without rubbing or damage.

Looking for the physics behind these terms — why the numbers matter and how the calculator uses them? Read the methodology.