Truck Wheel PCD & Bolt Pattern Chart
The bolt patterns that matter on commercial trucks, buses and trailers — with bolt-hole sizes, seat types and centre bores, drawn from our factory catalogue of 110 wheel models. Plus: how to measure a PCD, and the seat-type trap that catches buyers who match the pattern alone.
PCD in one paragraph
PCD — pitch circle diameter — is the diameter of the invisible circle running through the centres of all the bolt holes, quoted as number of studs × diameter in mm (e.g. 10×335). Because truck wheels use even stud counts, you can measure it directly: centre of one hole to the centre of the hole straight across. Between adjacent holes, the maths is PCD = adjacent spacing ÷ sin(180°/n).
The patterns that matter on commercial vehicles
| Pattern | Bolt-hole Ø | Seat / piloting | Centre bore | Typical wheel sizes | Typically found on |
|---|---|---|---|---|---|
| 10×335 | Ø26 (also Ø27, Ø30, Ø32) | Hub-piloted, flat seat + flange nut (M22); ball-seat versions exist | 281 mm | 22.5×7.50–9.00+, 19.5×12.25 | ISO fitment: European trucks, current Chinese heavy trucks, Japanese trucks after the ISO changeover (~2010) |
| 10×285.75 | Ø26 | Hub-piloted "unimount", flange nut | 220 mm | 22.5×8.25, 22.5×9.00 | North American & Mexican fleets, many export trailers |
| 10×285.75 | Ø32.5 | Ball seat, stud-piloted (double cap nut, "Budd") | 221.5 mm | 22.5×8.25, 22.5×9.00 | Older North-American-pattern trucks and trailers |
| 8×285 | Ø32.5 | JIS ball seat | 221 mm | 22.5×7.50–9.00 | Japanese-built heavy trucks (pre-ISO) — still common across East & Southern Africa's used-import fleets |
| 8×275 | Ø32 | JIS ball seat | 214 mm | 19.5×6.00–12.25, 22.5×6.00–7.50 | Japanese medium trucks |
| 6×222.25 | Ø32 | JIS ball seat | 163–164 mm | 17.5×6.00, 19.5×6.75, 22.5×6.00–6.75 | Japanese light/medium trucks |
| 10×225 | Ø26 | Hub-piloted, flange nut | 176 mm | 17.5×6.75 | European trailer axles (BPW-type) on 17.5" running gear |
Hole diameters, seat forms and centre bores above are taken from our own production catalogue — the same model tables published in the wheel technical catalogue (4 series, 110 models). Variants beyond this table exist; if your pattern isn't here, it almost certainly is in the catalogue.
The seat-type trap: same PCD ≠ same wheel
The most expensive fitment mistake in this business is matching the PCD and ignoring the seat. A 10×285.75 hub-piloted wheel (flat seat, Ø26 holes, flange nuts, located on the hub pilots) and a 10×285.75 ball-seat wheel (spherical seats, Ø32.5 holes, located by the nuts themselves) share a bolt pattern and share nothing else. Mount one on the other's hub and the wheel will seat wrongly, the nuts will work loose, and the bolt holes will crack — a failure mode, not an inconvenience.
- Hub-piloted: flat seat, smaller holes (Ø26), the wheel centres on machined pilots on the hub; one flange nut per stud, singles and duals alike.
- Stud-piloted / ball seat: spherical seats, larger holes (Ø32+), the nuts centre the wheel; dual assemblies use inner and outer cap nuts.
- Check the stamping and the nut type on the vehicle before ordering — or send us photos of both and we confirm the fitment.
Why mixed fleets make this harder in Africa and Latin America
An East African fleet routinely runs used Japanese trucks (JIS ball-seat patterns), new Chinese trucks (ISO 10×335 hub-piloted) and imported trailers (ISO or North American patterns) side by side. Mexican fleets mix North American 285.75 fitments with European-pattern tractors. That is why a parts wholesaler's wheel order is rarely one specification — and why a supplier that produces across all three families (ISO, North American, JIS) out of one catalogue saves you consolidation headaches. Ours does: see the steel wheels & rims line.
What to send us for a fitment check
- A photo of the wheel stamping (size, pattern and date code are usually stamped near the valve hole or on the disc face);
- A photo of the hub with the nuts visible (tells us piloting and seat type at a glance);
- The tyre size on the vehicle (confirms rim width and diameter);
- If available: axle brand and model — trailer axles (BPW, FUWA, York) map to known patterns instantly.
Frequently asked questions
What is the standard 22.5" truck wheel bolt pattern?
Two patterns dominate: 10×335 hub-piloted (ISO — Europe, current China, post-changeover Japan) and 10×285.75 (North America; hub-piloted unimount or older ball-seat). The same wheel size is made in both — the pattern must come from the vehicle, not the wheel size.
How do I measure PCD on a 10-stud wheel?
Measure centre-to-centre straight across to the opposite hole — that distance is the PCD. Verify with a second pair of holes to rule out an oval measurement.
My pattern isn't in the chart — can you still supply?
The chart shows the most common families. The full catalogue runs to 110 models across 16"–24.5", and custom drillings are a normal OEM request — send the drawing.
Tell Us What You Need
Share your drawing, target dimensions or application — our engineers will get back to you with a spec check and quotation.