Common Terms Related to Alloy Wheels: Explained

Filed in Blog by on June 8, 2016 0 Comments

When you are purchasing alloy wheels, it is likely that a lot of ‘strange’ terms will be thrown in your direction. On this page, we are going to decipher some of the most common of these terms. This is not a complete guide. If you do run into any issues, then feel free to get in touch with our team who will be more than happy to help you out.

Offset (or ET, as it is sometimes referred)
This measures the distance between the mounting face of the hub and the centre line of the wheel. This number can be one of three things:
- Positive: the majority of wheels will have a positive offset. The only real exception to this is older vehicles and vehicles that are four-wheel drive.
- Zero offset. This is known as ET 0
- Negative offset. This is incredibly common on rear-wheel drive vehicles.

PCD
This is known as ‘Pitch Circle Diameter’. It is, essentially, the number of bolts that your wheel has and how far they are spaced apart. So, for instance, if you have 5 studs and they are placed 100mm apart, this will be known as 5x100. This information should be available in your vehicle’s user manual or online. If you are still unsure, then you should talk to your alloy wheels vendor.

Centrebore
This is the size of the hole on the wheel which you will be clipping your hub cap into. It is absolutely vital that you get the right size here otherwise it will not fit snuggly inside of the wheel. If you have a vehicle that is hub-centric, then it is important that the right size hole is selected as this is what will be bearing the load of the cap. If you have an older vehicle, you may have lug-centric caps. All of the weight will be placed on the bolts on these. It is, therefore, incredibly vital that you do check the condition of those bolts from time to time. The last thing you want is for your cap to fall off!

Plus-sizing
This is a term which is often thrown around in alloy wheel circles. Plus-sizing means that you are reducing the profile of the tyres whilst at the same time increasing the size of the wheels. The radius stays the same at all times. Plus-sizing, particularly when you go up a couple of sizes, is known to improve car feedback. This is why you see many professional racing drivers with lower profile tyres. However, when the wheel is bigger, the weight of the car is going to go up. So there are, of course, pros and cons to plus-sizing.

Remember, if you are unsure of any term related to alloy wheels, the team here will be able to help you out. All you need to do is pick up that telephone and give us a call. We will even be able to help you get fitted for the right alloy wheels!

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