ARE WHEEL SPACERS SAFE?! WILL THEY KILL ME??
Are spacers safe? Will they cause my wheels to fall off? Will they cause vibrations?
A very loaded series of questions! In this article, we will go over some of the important talking points when it comes to wheel spacers. Spacers tend to be a very polarizing topic in the automotive community. Either people won't go near them, or they use them all the time. Personally, we find that most of the failures related to wheel spacers are caused more by user error or misinformation, rather than being caused by the spacer itself.
For the staff here at Summit, we tend to feel that spacers are perfectly safe when installed correctly. Let's go over some important points to ensure that if you decide to get spacers, you can be as educated as possible when buying.
The Purpose of a Wheel Spacer
A spacer goes in between the wheel and the hub of your vehicle essentially pushing the wheel further out, adding more backspacing and negative offset. For clarification on this, check out our other article about backspacing and 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.
There are two main types of spacers, slip-on, and bolt-on. Slip-on spacers slide over your wheel studs and are sandwiched by the wheel and your vehicle's wheel hub. Bolt-on spacers as the name suggests, bolt-on to your wheel studs, and then provide it's own studs to bolt the wheels too.
Important Concerns with Slip-On Spacers
When provided the option, hub-centric spacers should always be used. They allow the spacers to sit centered on your hub, rather than dangle off the studs. Wheel vibrations after installing spacers are almost exclusively caused by not using hub-centric spacers.
Secondly, when using slip-on spacers, making sure there is enough thread engagement left for the lug nuts is essential. Because slip on spacers push the wheels further out on the same set of studs the wheels go on, they also reduce the amount of stud left for the lug nuts. As a rule of thumb, you want at least the same amount of engagement as the stud is wide. For example, an M12x1.5 stud would need at least 12mm of thread engagement to be safe. At a 1.5mm thread pitch, 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 be safe.
Important Concerns with Bolt-on Spacers
As with the slip-on spacers, make sure to always purchase the hub-centric variant. This will ensure balanced wheel rotation, which is especially important due to the heavier and thicker nature of bolt-on spacers.
Additionally, because bolt-on spacers double the number of studs and nuts per wheel, you need to be extra vigilant on checking all lug nuts are torqued down properly. Once the wheel is installed, we tend to forget there is another set of 5 or 6 lug nuts that could potentially get loose apart from the ones holding the wheel on to the spacer. After installing bolt-on spacers, it is a good idea to remove all wheels after 100 or so miles to double-check the torque on all the lug nuts. It is also a good habit to check torque specs before and after each offroad trip, regardless if you have spacers or not.
Spacers have been around for multiple decades, and as long as they are installed correctly, there is very little opportunity for failure. Things tend to be sensationalized on the internet, especially because no one wants to admit they forgot to tighten lug nuts, or purchased auto-zone slip on spacers.
Spacers have always been used extensively, even within the highest level of Motorsports. Here we see nearly 4 inches (more than you would ever normally see or use) on a 1200 HP competition drift car, for a full season, with no failures. Follow our guide, follow good maintenance checklists, and you should be good to go! Thanks for stopping by and check back for more technical articles!