When ordering new wheels, hubs or brake dums for your trailer, you will always be asked “what is the PCD?” At first, this question may seem daunting but without this information, suppliers cannot guarantee that your new parts are goint to fit.

The Pitch Circle Diameter (PCD) is the diameter of an imaginary circle drawn through the centres of the holes/studs in either your wheel or hub/drum.

4 Stud PCD

4 Stud PCD trailer wheels can usually be broken down into 5 main types, as follows:

4 Stud 4″ PCD Wheel Rims

• Will usually have 3/8″ diameter studs & nuts
• Centre bore measures 60mm diameter
• Usually has a cut-out on the centre bore for a grease nipple
• Measures 4″ (101.6mm) between the studs (measured diagonally)

4 Stud 100mm PCD Wheel Rims

• Will usually have M12 diameter studs & nuts
• Centre bore measures 66mm diameter
• Some wheels can have a 57mm centre hole
• Measures 100mm between the studs (measured diagonally)

4 Stud 5.5″ PCD Wheel Rims

• Will usually have M12 or 1/2″ diameter studs & nuts
• Centre bore measures 96mm diameter
• Measures 5.5″ (139.7mm) between the studs (measured diagonally)

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5 Stud PCD

5 Stud PCD trailer wheels can usually be broken down into 3 main types, as follows:

5 Stud 6.5″ PCD Wheel Rims

• Will usually have M16 diameter studs & nuts (Ifor Williams Trailers may have M14)
• Centre bore measures 114mm diameter
• Measures 6.5″ (165.1mm) between the studs (measured diagonally)

5 Stud 112mm PCD Wheel Rims

• Will usually have M12 diameter studs & nuts
• Centre bore measures 66mm diameter
• Measures 112mm between the studs (measured diagonally)

5 Stud 140mm PCD Wheel Rims – NO LONGER AVAILABLE/MANUFACTURED

• Will usually have M16 diameter studs & nuts
• Centre bore measures 94mm diameter
• Measures 140mm between the studs (measured diagonally)