Bolt Pattern/Pitch Circle Diameter (PCD)
PCD (Pitch Circle Diameter) is the measurement of the diameter of the imaginary circle drawn through all of the wheel bolts or studs on a wheel. It is also known as the 'bolt circle'.
A wheel's PCD is usually displayed after the number of studs, separated by a slash. Hence a 'pcd' of 5/120 means that the wheel has five studs, and a pitch circle diameter of 120mm. A 'pcd' of 4/114.3 means the wheel is four stud with a pitch circle diameter of 114.3mm.
Measuring the PCD of a 5 stud wheel is a tricky business. It is much easier to determine the PCD by checking the manufacturers' original specifications or by checking our PCD reference guide for each model. It is possible to roughly measure the PCD of a 4 stud wheel, as the pitch circle diameter is the same as the distance between two opposite bolt centres.
Different cars have different PCDs, but often similar cars within the same manufacturers group have the same PCD. Many of the VW Golf-sized cars in the VAG range have the same PCD and other wheel dimensions, meaning that wheels are often interchangeable between these cars.
The PCD has to do with the sizing of the diameter of a circle that the lug holes create. The center of every bolt/lug lies on the circumference of a circle that they create. PCD is usually measured in millimeters (mm).
For example, the 5x114.3 (or 5x4.5 in inches) PCD that our 3G TLs use means that there are 5 lug holes, with a pitch circle diameter of 114.3mm or 4.5in.
Video explaining EVERYTHING about wheels and fitment. I go over what offset means, what lug patterns are, and how to read wheel and tires measurements and specs. This is only Part 1, Part 2 will go over Spacers, Hubcentric rings, Lug Bolts, Coilovers, etc.
This is part 2 of my stance and wheel fitment guide. In this part I explain Spacers and extended lug bolts. Any
This video will show you how to properly measure a bolt pattern on a 5-lug wheel. www.coyswheel.com (801) 426-4736
For more information visit http://www.alloywheelfitments.com How to measure a Wheel Bolt Pattern
The offset of a vehicle's wheel is the distance between the centerline of the wheel and the plane of the hub-mounting surface of the wheel. It can thus be either positive or negative, and is typically measured in millimeters. Offset has a significant effect on many elements of a vehicle's...
The centre bore is the size of the hole in the centre of the wheel where the spigot fits through. The centre bore, (also known as spigot size), is the diameter of this hole, usually measured in millimetres. For most road wheels, the weight of the car is transmitted from the...
Bolt pattern in metric or inches
The metric unit is the most common one and is today used by both vehicle- and wheel manufacturers, although some may also provide the measurement written in inches. The units in inches is otherwise mainly used in the USA when talking about classic cars, but also regarding newer vehicles and...