How to calculate the PCD (Pitch circle diameter)

The Pitch Circle Diameter (PCD) is the diameter of the circle which passes through the centre of all the studs, wheel bolts or wheel rim holes.

The easiest way calculate the PCD is as follows:

  1. Identify the size of rim or tyre size. (This helps to narrow down the likely PCD sizes)
  2. Measure the distance 'S' between two adjacent studs from the centre of each hole.
  3. Using the calculator enter the number of studs/holes & 'S' and press 'calculate'.
  4. Using the relevant diagram depending on the number of studs you have you should be able to identify the correct PCD.

Note: Imperial sizes are commonly used on UK trailers whereas European trailers use metric.

Image

PDC Calculator

mm
Rim Size
Studs
    S
 
PCD
8" Rim 3 76.90mm   88.8mm
  3 95.26mm   110mm
 
4
70.71mm
 
100mm
4
71.84mm
 
101.6mm (4")
4
81.32mm
 
115mm
4
91.92mm
 
130mm
     
10" Rim
4
70.71mm
 
100mm
 
4
71.84mm
 
101.6mm (4")
 
4
79.20mm
 
112mm
 
5
65.83mm
 
112mm
 
4
81.32mm
 
115mm
 
4
91.92mm
 
130mm
 
4
98.78mm
 
139.7mm (5½")
       
12" Rim
4
70.71mm
 
100mm
 
4
71.84mm
 
101.6mm (4")
 
5
65.83mm
 
112mm
 
4
91.92mm
 
130mm
 
4
98.78mm
 
139.7mm (5½")
 
5
82.29mm
 
140mm
 
5
97.04mm
 
165.1mm (6½")
       
13" Rim
4
70.71mm
 
100mm
 
4
79.20mm
 
112mm
 
5
65.83mm
 
112mm
 
4
91.92mm
 
130mm
 
4
98.78mm
 
139.7mm (5½")
 
5
82.29mm
 
140mm
 
5
97.04mm
 
165.1mm (6½")
       
14" Rim
4
70.71mm
 
100mm
 
5
65.83mm
 
112mm
 
5
82.29mm
 
140mm
 
5
89.58mm
 
152.4mm (6")
 
6
102.5mm
 
205mm
       
16" Rim
5
97.04mm
 
165.1mm (6½")

PCD Calculation Formula


4 Stud PCD = S  
0.7071
     
5 Stud PCD = S  
0.5878  
     
6 Stud PCD = S  
0.5  

How to find the Offset of a wheel rim

Please Click Here If you need to find the OFFSET of the wheel rim.