An off-road spacer is a kind of car accessory that is installed between the wheel and the vehicle hub. The main function is to push the wheel further out, adding more backspacing and negative offset. This is done for a couple of different reasons, sometimes for aesthetic purposes, or other times, to help wheels clear suspension/brake/protruding hubs. For off-road vehicles, installing wheel spacers helps to increase the distance between the left wheels and the right wheels, hence increasing the traction. This is effective when your 4×4 machine is driven in bad weather or when crawling rocks. When provided the option of your off-roading modifications, hub-centric spacers should always be used. The hub-centric design allows the spacers to sit centered on your hub, rather than dangle off the studs. Most wheel vibrations after installing spacers are exclusively caused by not using hub-centric spacers.
Types of 4×4 Rim Spacers
Among the marketplace, there are two main types of spacers: slip-on and bolt-on. Slip-on spacers directly slide over the wheel studs and are sandwiched by the wheel and the vehicle hub. Bolt-on wheel spacers are bolted to the existing studs with the provided lug nuts and then secure the wheel on the spacer with the stock lug nuts. When using slip-on spacers, it is essential to ensure that there is enough thread engagement left for the lug studs. Since slip-on spacers push the wheels further out on the same set of studs the wheels bolted on, they also reduce the amount of stud left for the lug nuts. Based on experience, you need at least the same amount of engagement as the width of the stud. For example, an M12x1.5 stud would require at least 12mm of thread engagement to be safe. At a thread pitch of 1.5 mm, this equates to about 8 full turns of the lug nut. If you cannot achieve this, you will need to switch to extended studs to ensure safety.
In addition, because the bolt-on spacers double the number of studs and nuts per wheel, you need to be extra careful to check that all lug nuts are properly torqued down. After installing bolt-on spacers, it is a good idea to double-check whether all lug nuts are tightened to the manufacturer’s specification with a properly calibrated torque wrench. It is always a great idea to regularly inspect torque specs before and after each off-road trip, regardless if you have spacers or not. Give the spacers another check after 100 miles of driving to make sure they’re still in place well and double-check the torque on all the lug nuts. Spacers have existed around for multiple decades, and as long as they are high-quality and installed correctly, there is very little opportunity for wheel spacer failure.