A wheel bolt pattern (PCD) is written as number-of-studs × circle diameter — for example 6×139.7mm (6×5.5"). To fit new wheels or replace a hub, match both the stud count and the pitch circle diameter, plus the centre bore and stud thread. This guide shows you how to measure your pattern and match wheels, studs, and hubs for off-road trailers.
What "bolt pattern" means
The bolt pattern (also called PCD — pitch circle diameter) is the number of wheel studs and the diameter of the imaginary circle through their centres. Common off-road trailer patterns include 6×139.7mm (6×5.5") and 5×114.3mm (5×4.5"). The wheel must match this exactly to bolt up.
How to measure your bolt pattern
- Even stud counts (4, 6, 8): measure centre-to-centre across two directly opposite studs.
- Odd / 5-stud: measure from the back of one stud to the centre of the stud two places over (or use a bolt-pattern gauge).
- Note the measurement in mm and inches to match listings either way.
Also match these
| Spec | Why it matters |
|---|---|
| Stud count + PCD | The wheel won't bolt up unless both match |
| Centre bore | Hub-centric fit; too small won't seat, too large needs spigot rings |
| Stud thread & seat | Thread size/pitch and taper vs flat seat must match the nuts |
| Offset / backspacing | Keeps the tyre clear of the guard and suspension |
| Load rating | Wheel must carry the trailer's loaded weight (see the tire guide) |
Sizing tyres too? See the brakes, suspension, tires & wheels collection and our off-road trailer tire buying guide.
Studs & hubs
If you're replacing a hub or studs (e.g. after a bearing service), match the stud count, PCD, stud thread, and hub type to your axle. Shop brake drums, hubs & wheels. See also our wheel bearing and brake-drum service guides.
FAQ
What is a 6×139.7 bolt pattern?
Six studs on a 139.7mm (5.5") pitch circle — a common off-road trailer and light-truck pattern. The wheel must match both the stud count and the diameter.
How do I measure a 5-stud pattern?
Measure from the back of one stud to the centre of the stud two positions away, or use a bolt-pattern gauge — straight across won't work with an odd stud count.
Will any wheel with the right pattern fit?
It also needs the right centre bore, offset/backspacing, stud thread and seat, and load rating — match all of these, not just the bolt pattern.
Can I change my bolt pattern?
Only with adapters or a new hub/axle, which has safety implications — usually it's better to buy wheels that match your existing pattern.
Match your wheels & hubs: shop trailer wheels, studs & hubs — in stock, ships from Upland, CA.