Views: 4196


With so many design styles available, choosing the right alloy wheel for your vehicle is a tough decision. But aside from eye-catching good looks, selecting the appropriate dimensions is a far more important requirement.


Not all rims will fit all vehicles, so knowing how to read wheel dimensions is a critical part of the buying process. What you don’t want, is to be in a situation where you find your dream wheels, only to be told that the bolt pattern or PCD won’t fit your vehicle model.


For this reason, you want the information beforehand so that you can browse rim options that will only fit your vehicle.


On that note, here’s what you need to know about wheel dimensions…



It goes without saying that the diameter of the wheel must match the diameter of the tyre. However, that’s not to say that you can’t upsize or downsize your wheel diameter; it just means that if you wish to do so, you’ll have to replace your tyres to match the newly sized wheel diameter, too.


Increasing the diameter of your wheels will generally decrease the profile (height) of your tyres. This often makes the rim- and tyre combination look “sportier”.



In contrast, decreasing the rim diameter will generally increase the tyre’s profile. This setup is often favoured by 4x4 enthusiasts who want the extra “cushioning” effect of a taller tyre off-road.


Note: Wheel diameters are always quoted in inches.



The bolt pattern details the number of mounting holes within the rim. Most rims have a bolt pattern of 4, 5, 6 or 8 holes. The pattern depends on the vehicle make and model, and cannot be changed.


Some aftermarket suppliers may use wheel adaptors to widen the range of wheels available for certain vehicle models. However, wheel adaptors are notoriously unsafe and are not recommended.



Otherwise known as the PCD, the Pitch Circle Diameter refers to the circular diameter through the bolt holes. This information tells the fitment specialist how far apart the bolt holes are spaced.


It also means that, just because your vehicle has the same bolt pattern as a specific rim, it won’t automatically fit. The wheel’s bolt pattern, as well as the PCD, must match your vehicle in order for the wheel to fit.



Generally covered by a dust cap or logo cover, the centre bore helps to centralise the rim in order to align the bolt holes. It may also allow access to the driveshaft retaining nut.


In some cases, the centre bore of an aftermarket rim may be larger than the centre bore of your factory-fitted wheels. Fortunately, however, a spigot ring will often let you fit your preferred alloy by making up the difference between the two bore sizes.



The offset of a rim determines how far ‘in’ or ‘out’ the wheel will sit in relation to the vehicle’s body. That said, there are three types of offset…


Positive offset: The wheel sits deeper under the body.

Zero offset: The wheel sits in line with the body.

Negative offset: The wheel extends beyond the body.


In most instances, a negative offset will give your vehicle an aggressive stance. However, a negative offset isn’t always possible, and largely depends on your vehicle’s suspension travel, as well as the clearance between the tyre and the vehicle’s wheel arch.


If your chosen rim has too much negative offset, as well as too little clearance between the tyre and the vehicle’s body, there’s good chance that the tyre will rub on the inside of the wheel arch.



Last but not least: If you’re swapping your vehicle’s standard tyres for a wider, aftermarket set, you may need a wider rim to accommodate the wider tyres.


Fitting a wide tyre onto a narrow rim – or even a narrow tyre onto a wide rim – will cause unwanted strain on your tyre’s sidewall. The result is often a reduction in tyre performance, longevity, and reliability.



Unfortunately, choosing the right wheel isn’t as straight forward as we’d all like it to be, but it is a vitally important step before you start browsing.


That said, if you’d like help finding the best looking – and best fitting – aftermarket rims for your vehicle, as well as expert wheel- and tyre advice, style comparisons, PCD options, and up-to-date LIVE prices, click here.


Share this

Other Articles