Wheel Offset, Wheel Bolt Pattern, & Plus Sizing Tires Explained

Those new to buying car or truck rims may be asking yourself, what does wheel offset mean? The offset of a rim is usually stamped on the wheel and is measured in millimeters of ET. So now you may be wondering, what in the world is ET???? Well, ET is the abbreviation of the German word Einpresstiefe, this means insertion depth in English. The offset is the distance between the center mounting face, or the hub, and the center-line of the wheel. Negative Offset wheels have their mounting face going rearward to the wheel.

You’ll usually find that powerful rear wheel drive cars have negative offset wheels. There are wheels with zero offset, these kind of wheel’s mounting face is even with the center-line of the wheel. They are by defined as ET0. Positive offset wheels have their mounting face toward the front of the wheel. Front wheel drive cars and trucks usually have positive ET type rims. Volkswagen’s that were made in the 80′s and 90′s generally have ET38 wheels.

We’ll now talk about PCD. PCD means “Pitch Circle Diameter” and this is the diameter of the circle drawn through the center of bolt holes in your wheel. PCD is measured in millimeters, it also specifies the number of studs or bolts needed for the wheel. A Volkswagen’s alloy wheels are typically either 4×100; which means 4 bolt holes drilled through the center of an imaginary circle that measures 100mm, or 5×100 for your VR6′s, MK4′s and GTi’s.

The center hole of an alloy wheel is where the hub fits into the wheel. This will help the wheels seat properly when the hole is exactly the size of the hub. Most wheels of today are what is called “hub-centric”. This means that the hub that extends from the vehicle and matches up with a similar size hole in the wheel carries a load. All that your studs and/or bolts do is hold the wheel on the hub. When it comes to lug-centric wheels, paying attention to your studs or bolts is obviously important. You should be sure to replace these ever so often, and always 3/4 tighten the wheels to the car to make sure they are centered properly.

To plus-size or Up-Step your wheels are terms used to define the practice of increasing the diameter of the wheels while at the same time you reduce the profile of your tires to keep the stock rolling radius. Plus-sizing has some key benefits, such as increasing the handling of your car. Each step will reduce the proportion of your soft-sided tires relative to the alloy wheel rim. This will improve response, and will help keep the tread perpendicular to the road and improve road feel of the car. If done properly, the accuracy of the speedometer and odometer will stay intact, and the car will feel and look better.

Some of the disadvantages of plus-sizing is that tires are lighter than wheels. So plus-sizing can make the overall wheel and tire package heavier. Reduction of the tires also reduce the ability dampen your car from bumps and other imperfections of the road. Other disadvantages are the need for more expensive tires, and if you don’t upgrade to bigger brakes, you’ll have other car buffs laughing at your undersized calipers and rotors.

Discover more about Tires & Wheels, and play around with the numbers for your car. You can even virtually choose the size and style of rim you want. Use the “see on my vehicle” option so you can choose your car color, this will allow you to see what the rims and tires will look like on your car today.

Related Websites

Incoming search terms:

upstep tire size (1)
wheel offset explained (1)