One of the recurring events in the automotive aftermarket retail world is the customer who comes through the door because he/she just bought a set of used wheels on Craigslist or eBay or… (substitute your favorite used parts on-line classified website here). Problem is, they don’t fit and the customer wants help figuring out what they need to do to make them work.
There are several factors that determine whether a wheel will fit a particular vehicle and they all must work together. They are:
Bolt pattern – the number of holes in the wheel that the wheel studs come through and the distance between them. Typical bolt patterns can be found here:
Wheels that have the wrong bolt pattern can still be mounted but it requires a wheel adapter. These are often expensive and people end up spending more than expected just to save their “good” used wheel deal. Depending on the difference between wheel and vehicle bolt patterns, there can be cases where no adapter is available for that combination and the customer has no option but to try to resell their now-useless wheels. Also, the wrong wheel adapter style for the vehicle can result in a wheel coming off while driving.
Bore Size – the size (in millimeters) of the hole in the center of the wheel. This hole should be as close as possible to the hub size of the vehicle on which the wheel will be mounted without being smaller. If the bore size is close, a small adapter known as a hub-centric ring will fill the space between the wheel bore size and the vehicle hub size. Too much difference, however, and there will not be a ring large enough to allow safe mounting of the wheel.
Offset – this is the point between the outside and inside edge of the wheel where the mounting surface of the wheel is located. If the mounting surface is exactly halfway, the wheel is considered to have zero offset. If the mounting surface is closer to the inside edge than outside, the wheel has negative offset and the wheel is, in effect, pushed out toward the wheel opening in the fender. If the mounting surface is closer to the outside edge, the wheel is considered to have positive offset and the effect is to pull the wheel deeper inside the wheel well.
Backspacing – this is a term that is often used interchangeably with offset but it is not exactly the same. Backspacing is the distance from the inside edge of the wheel to the mounting surface. To translate backspacing into offset, you have to know the width of the wheel. It’s generally better and safer to focus on offset so you know how the wheel will be positioned in the wheel well.
Most vehicles come from the factory with positive offset wheels. The entire wheel fits completely inside the wheel well and still has sufficient clearance of stock suspension components. However, when the vehicle is lifted, the angle on some of the suspension components can change, bringing them into contact with the wheel. That’s why lifted vehicles usually need a more negative offset so the wheel is pushed out and away from the suspension. A stock 2017 Jeep Wrangler (JK), for example, comes from the factory with a positive 45mm offset. An aftermarket wheel, on the other hand, may have a positive offset of 18mm. That translates into a negative 27mm change in offset, pushing the wheel out to the edge of the wheel well or fender flare. The more the offset changes in a negative direction, the more the wheel is pushed out.
Wheel diameter – the distance across the wheel. Vehicles can often take larger diameter wheels than the factory designed them for, but usually not smaller (there are exceptions to this rule, especially when the same vehicle, with a lesser trim level, was built with smaller wheels). The issue here is brake clearance. The inside circle of the wheel must be large enough to not interfere with the movement of the brake calipers (disc brakes) or shoes (drum brakes).
The bottom line, of course, is that wheels are not a generic component that can be readily moved from one vehicle to another. If you are in the market for used wheels, follow these important steps:
- do your homework regarding the wheel requirements for the vehicle on which you will mount the wheels
- take along some measuring tools when you go to look at wheels to ensure (as much as practically possible) that the wheels will fit your vehicle without requiring additional spend to make them work properly
- If at all possible, do a test fit. Jack up your vehicle and mount the new wheel to make sure it fits properly. Turn it while observing clearance with suspension parts and position in the wheel well. Operate the brakes while turning it to see if there is any scraping or odd noises when the brakes are applied and then released.
- Get a money-back guarantee that the wheels will fit your vehicle. If the seller won’t provide that, it’s probably for a reason.
The reality is that there are lots of brand new aftermarket wheels that can be had for not much more than we’ve seen people pay for used wheels plus the pieces to make them work. Don’t rush into a “screaming deal” without checking out new wheel prices to see just how much “scream” there really is in the deal.
We all want to save money and used wheels can often be just the ticket for the informed buyer. With the information above and some due diligence on your part, hopefully that informed buyer is you.