PCD and centre bore: how a wheel is fixed
- Module: Dimensions
- Level: Intermediate
- Reading time: 9 min
The PCD (bolt pattern) of a wheel, written for example 5x112, gives the number of bolt holes (5) and the diameter of the circle that runs through their centres (112 mm). The centre bore is the diameter of the centre hole, for example 66.6 mm, which fits over the hub and centres the wheel. The PCD must be exactly that of the car; the centre bore must be that of the hub, or larger with a spigot ring that fills the gap. Then come the bolts or the nuts, whose bearing shape, the seat, must match that of the wheel.
A wheel can have the right size and the right offset: if it does not fit exactly on the hub, it is useless. Here are the four measurements of the fixing, how to read and measure them, and the mistakes that prove costly.
What does 5x112 mean on a wheel?
Around the centre hole, the bolt holes are spaced evenly on a circle: the pitch circle, whose diameter is the PCD (pitch circle diameter). The PCD describes it in two numbers:
- the number of holes, most often 4, 5 or 6 on a passenger car;
- the diameter of the circle that runs through the centre of these holes, in millimetres.
The same measurement is written in several ways:
| Written as | Where you find it | Reads as |
|---|---|---|
| 5x112 | Most manufacturers and sellers | 5 holes on a 112 mm circle |
| 112/5 or LK112/5 | German documents: Audi writes “Felgenlochkreis 112/5”, Volkswagen “LK112/5” | The same measurement, diameter first |
| 5x114.3 or 5x4.5″ | Measurements that started out in inches, which Ford also writes “114 mm (4.5″)” | 4.5 inches is exactly 114.3 mm |
| 6x139.7 or 6x5.5″ | Off-road vehicles and pick-ups | 5.5 inches is exactly 139.7 mm |
How do you measure a wheel's PCD?
The task is to find the diameter of an invisible circle by measuring between holes. With an even number of holes, it is straightforward; with five, it takes a calculation.
| Number of holes | Measure | Then |
|---|---|---|
| 4 or 6 | From the centre of one hole to the centre of the opposite hole | That is the PCD |
| 5 | From the centre of one hole to the centre of a neighbouring hole | Multiply by 1.701 |
| 4 | From the centre of one hole to the centre of a neighbouring hole | Multiply by 1.414 |
| 6 | From the centre of one hole to the centre of a neighbouring hole | Multiply by 2 |
| All | From the centre of one hole to the centre of the wheel | Multiply by 2 |
The coefficients come from the geometry of the circle: 1.701 is the inverse of the sine of 36°. Example: 65.8 mm between two neighbouring holes gives 65.8 × 1.701 = 111.9 mm, that is a PCD of 112 mm. To aim at the centre of the holes, measure from the left edge of one hole to the left edge of the next: the distance is the same as between the centres. A vernier caliper does better than a tape measure.
The expected distances between two neighbouring holes, for the most common 5-hole PCDs:
| PCD | Distance between two neighbouring holes |
|---|---|
| 5x98 | 57.6 mm |
| 5x100 | 58.8 mm |
| 5x108 | 63.5 mm |
| 5x110 | 64.7 mm |
| 5x112 | 65.8 mm |
| 5x114.3 | 67.2 mm |
| 5x120 | 70.5 mm |
| 5x130 | 76.4 mm |
Beware of a method you often read: “from the centre of one hole to the outer edge of the opposite hole”. With five holes, none is opposite another, and this measurement is out by one to two millimetres. Yet 5x112 and 5x114.3 differ by only 2.3 mm in diameter: it cannot tell them apart. When in doubt, the reference remains the manufacturer's document for the exact version of the car.
Which PCD for my car?
The one the manufacturer gives for the car's exact version. A make does not have a single PCD: it changes from one model to another, and sometimes from one generation of the same model to the next. The “by make” tables that circulate come from compiled databases, rarely from a manufacturer's document.
Here is what manufacturers write themselves, in their genuine accessories catalogues, recorded on 10 October 2026:
| Manufacturer | Car | PCD | Centre bore |
|---|---|---|---|
| Audi | A3 (8Y, since 2021) | 5x112 | not published |
| Audi | A4 and S4 (B9, 2016 to 2025) | 5x112 | not published |
| Audi | A6 (C8, 2019 to 2025) | 5x112 | not published |
| Audi | Q7 (4M, since 2016) | 5x112 | not published |
| Audi | RS 6 Avant (C8, since 2020) | 5x112 | not published |
| Ford | Mustang (2024 onwards) | 5x114.3 | not published |
| Ford | Bronco (2021 onwards) | 6x139.7 | 93.25 mm |
The table is short on purpose: we only put in it what a manufacturer's document states in black and white. The centre bore, in particular, does not appear in any of the European manufacturers' documents we were able to read. For your car, three reliable sources: the manufacturer's technical documentation, its dealer network, and the markings on the back of the original wheel.
What is the centre bore for?
The centre bore fits over the car's hub, the round part that sticks out in the middle. When the hole in the wheel has exactly the diameter of the hub, it is the hub that centres the wheel: the wheel is said to be hub-centric, which is what most cars and wheels do today. The bolts or the nuts then only have to press it against its mounting face.
In the past, and still on some vehicles, it was the conical or spherical seats of the bolts that centred the wheel. In both cases, a badly centred wheel runs out of true and vibrates, especially at high speed.
Spigot ring: when is it needed?
A spigot ring is a ring, made of plastic or aluminium, that slides into the wheel's centre bore to bring it down to the diameter of the hub. It is used for wheels bored wider than the hub, which is common when the same wheel is sold for several makes: some forged wheel makers supply them to adapt one wheel to several vehicles.
A wheel whose centre bore is machined to the exact diameter of the hub does not need one. That is the case with an original wheel, and with a wheel made to measure for a given car.
Bolts or nuts: how is the wheel tightened?
Two systems coexist:
- wheel bolts, which go through the wheel and screw into the hub. Audi, Volkswagen, Mercedes-Benz and Porsche refer to wheel bolts in their documents; Audi gives their thread for the RS 6 Avant: M14 x 1.5;
- studs and nuts: threaded rods fixed to the hub, onto which nuts are screwed. That is the case with the Tesla Model 3 and Model Y, and with the Ford Mustang and Bronco.
Some versions of the Porsche 911 have a single centre-lock nut instead of five bolts.
A wheel is not drilled a second time to give it another PCD: a redrilled hole weakens the area that carries all the force.
Conical, spherical or flat seat: why does it matter so much?
The head of the bolt, or the base of the nut, bears on the wheel through a surface of a precise shape: the seat. There are three families:
| Seat | Shape | What you need to know |
|---|---|---|
| Conical | A cone, most often at 60° | The angle must be that of the wheel's bolt holes |
| Spherical (or radius) | A portion of a sphere, with a radius of 13 or 14 mm for example | The radius must be that of the wheel |
| Flat | A flat face, often with a washer | Only for a wheel drilled for a flat seat |
The rule has no exception: the seat of the bolt must be that of the wheel. Regulation No. 124 requires the profile of the bolts and nuts to be compatible with the wheel, and fastener manufacturers forbid mixing shapes. A conical bolt in a spherical hole bears only on a line: the bolt seems correctly tightened with the wrench, then works loose on the road, until the wheel comes off. That is why the original bolts are not automatically refitted on a wheel from another maker: the shape of the seat must be checked, and the length too, so that the bolt goes far enough into the hub.
What tightening torque for a wheel?
The one given by the car's manufacturer, applied with a torque wrench, tightening in a star pattern, from one bolt to the one opposite. It varies from one car to another. Two examples taken from manufacturer documents:
- Porsche specifies 160 Nm for the wheel bolts of the 911 (generations 991 and 992) and of the 718, and 600 Nm for the centre-lock nut of the versions that have one;
- Tesla specifies 175 Nm for the nuts of the Model 3 (2024 onwards) and the Model Y.
Do not copy these values for another car. Three rules go with the torque:
- no grease on the threads or the seats, unless the manufacturer prescribes it: it skews the tightening;
- no impact gun to finish: you always finish with the torque wrench;
- a check after the first few kilometres: Regulation No. 124 requires the maker of a replacement wheel to prescribe re-tightening after 50 km, and some wheel or tyre makers speak of 50 to 100 km.
Costly mistakes
- Forcing a wheel onto a similar PCD. A 5x112 wheel on a 5x114.3 hub “seems” to go on, but the bolts sit at an angle.
- Forgetting the spigot ring on a wheel whose centre bore is larger than the hub.
- Refitting the original bolts without checking the shape of their seat and their length.
- Tightening by feel or with an impact gun, without finishing at the manufacturer's torque.
- Adding spacers without reviewing the length of the bolts: a spacer also moves the wheel, like a smaller offset.
The Onyx approach — In a made-to-measure project, the Onyx Forged design office establishes the PCD and centre bore of your car from its exact version, as shown on the registration document, and presents them to you before machining. Each Onyx Forged wheel is designed to these measurements: no spacer or spigot ring is needed.
Frequently asked questions
Can a 5x112 wheel be fitted on a 5x114.3 car?
No. The two circles differ by 2.3 mm in diameter: the holes do not line up with the fixings, and the wheel would be tightened at an angle.
Where is the PCD marked on a wheel?
When it is marked, it is on the back of the wheel, on a spoke or around the mounting area, in the form “5x112” or “LK112/5” for example. No regulation requires it: otherwise, it has to be measured.
Is a spigot ring mandatory?
As soon as the wheel's centre bore is larger than the car's hub, yes. With a centre bore at the exact diameter of the hub, there is no need for one.
Does the PCD change the position of the wheel?
No. The PCD only fixes the wheel; its position in the wheel arch depends on the offset and the width. The offset calculator compares two wheels from that point of view.
You have finished the module on dimensions: you know how to read a wheel, position it and fix it. On to the most creative module, style: fitment, concave profile and colour.
Lesson written by the Onyx Forged design office.
This lesson is part of the Onyx Academy, the free course on custom forged wheels.