EXPLAINED: What Car Rim PCD is, and why it must be factored when changing car rims
When changing a car's rims, one needs to factor the Pitch Centre Diameter (PCD) in to be sure whether the new car rims they are buying will fit their car. PCD is the diameter of an imaginary circle passing through the centre of all bolts in a wheel. In other words, this indicates the distance between the centres of two diagonal bolts.
The PCD of a car's rim varies depending upon the manufacturer, model and car size. Most passenger cars wheels come with 3 to 6 bolts for each wheel; the larger the wheel, the larger is the number of bolts. Car Rim PCD is expressed as 'number of bolts X pitch centre diameter'. Larger vehicles such as trucks and buses generally have around 10 bolts and a larger rim PCD.
Over the years, the number of unique variations in car rim PCDs has reduced significantly as vehicle manufacturers appear to be moving towards standardisation.
It is expressed as number of bolts X pitch centre diameter and calculated with the following formula:
4 bolts = S/0.7071
5 bolts = S/0.5878
6 bolts = S/0.5
(Here, 'S' is the distance between the centres of two adjacent bolts in millimetres.)
For example, 2018 Toyota Camry's PCD is 5x114.3. This implies its rims have 5 bolts, with a diameter of 114.3 millimetres. Manufacturers choose the safe number of bolts and the PCD of cars' rims based on the wheel size, vehicle weight, and engine power among other things.
Here are PCDs of some of the most popular vehicles sold in Australia:
1. Toyota Hilux (2018) = 6x139.7
2. Toyota Corolla (2018) = 5x114.3
3. Mazda 3 (2018) = 5x114.3
4. Holden Commodore (2017) = 5x120
5. Hyundai i20 (2018) = 4x100
6. Volkswagen Polo (2018) = 5x100
7. Mazda CX-5 (2017) = 5x114.3
8. Ford Ranger (2017) = 6x139.7
Before choosing new car rims, one must factor the number of bolts and PCD. The new car rims will not fit your car unless the number of bolts and PCD of your car and the rims is an exact match. If you get car rims whose PCD is even a few millimetres different from your car's PCD, your new
rims just won't fit!
One must also bear in mind that changing car rims can impact noise, braking, stability, performance and overall ride quality. Ideally, one should stick to the existing measurements of tyre and rim but it is possible to change these if you want to customise your car. The general rule of thumb is that, you wheel size can go up or down by one inch. However there are many variables, so it is best to get an
expert's advice before making any purchase.
Can you get larger rims for your car?
Yes, you can get larger or smaller rims for your car as long as the car's rim PCD is the same. For larger rims, you will also need bigger tyres which happen to reduce noise and make driving on freeways or highways enjoyable. Larger wheels have a bigger cushion between your car and the road, which translates to a very smooth and comfortable ride. This could improve ride quality by a few notches for those people whose regular travel is in an area with unpaved roads.
On the downside, bigger tyres may rub against the car's body, making the tyres thread and sides wear off quicker and also cause steering difficulty. If this is a problem, you can opt for tyres with a low profile to prevent tyres from rubbing against the car's body. Low-profile tyres generally have a firmer grip, better traction, and reduced roll because of thinner side walls. However, these are noisier than other tyres and can make your ride bumpier. So, these are definitely not recommended
for those who want a smoother ride.
While you can change your car's rims and tyres, you must remember that your choice of car rims is restricted by your car's rim PCD. To understand how you can customise your car's rims without a hitch, call 1300 60 90 96 to speak with a wheels expert at OxWheels today!