Wheel spacers, like the set below from Low Range Off-Road, have a somewhat dubious reputation in the off-road community. Some people argue that wheel spacers are not built for off-road use, while others say that they have used spacers off-road for years without any trouble.
The thing is, both points of view are correct. Wheel spacers can fail off-road, but they can also last forever…because not all wheel spacers are the same. Here’s what you need to know:
Why You Might Want Wheel Spacers
Let’s say that you want to add a wider set of tires to your Toyota Tacoma in order to enhance off-road performance (find more info about Tacoma tire sizes here). Unless you want the wider-than-stock tires to rub up against your suspension components, you either need to buy a new set of wheels with less backspacing (so the tire is further away from the hub) or you need to invest in a wheel spacer.
Wheel spacers can also be used to keep your wheels from running into your brake calipers. If you install a set of after-market wheels with incorrect backspacing, spacers can help correct the problem. If you add a set of big brake calipers that require more clearance, wheel spacers can fix that too.
Different Wheel Spacer Designs
There are two different types of spacers available. The first type is a simple “washer” type wheel spacer that sits between the wheel and the hub just like a washer.
Washer-type spacers are the least expensive option because they don’t include any new mounting hardware, but they’re really not a smart choice if you need more than a few millimeters of additional clearance.
The reason? Washer type wheel spacers reduce the number of threads that your lug nuts can grab onto. If you add a 15mm washer-type spacer to your vehicle, you’re taking away 15mm of wheel stud length…and that means that your lug nuts won’t have as much stud to fasten themselves too. Obviously, fewer threads = greater likelihood of loose lugnuts.
Bolt-on type wheel spacers are the better choice for anyone who needs to add a large amount of clearance. Bolt-on type spacers are sort of like hub extensions…they bolt on to the existing hub, and then the wheel bolts onto the spacer.
Bolt-on wheel spacers can be purchased in thicknesses as great as 2″ for many Toyota trucks, and in the case of the Tacoma that can allow for significantly wider tires. However, not all bolt-on spacers are created the same.
Quality is Important When Buying a Wheel Spacer
Some wheel spacers are machined from billet aluminum, a very strong material that’s unlikely to break in any situation. Other wheel spacers are made from cast aluminum, and these are less desirable because:
- Cast aluminum is less structurally consistent than billet aluminum because the casting process creates a less uniform crystalline structure
- Cast aluminum is much more difficult to manufacture with precision – it’s not uncommon to see cast aluminum spacers that aren’t uniform in thickness, perfectly circular, etc. If a spacer is out of round it can cause a lot of problems.
Cast aluminum is definitely cheaper than machined billet aluminum, but this isn’t a situation where you want to save money. Be sure to go with machined billet aluminum.
Note: Steel is a material choice as well, but it’s usually only found on heavy-duty trucks. Steel spacers really increase unsprung weight, and unless you have a big, burly commercial truck, the increase in unsprung suspension weight from a set of steel spacers will impact your truck’s ride pretty negatively.
Downsides to All Wheel Spacers
All wheel spacers suffer from the same problems/concerns:
Proper seating is critical to safety. You need to torque the bolts on your spacer and then re-torque them again after a few miles, with a torque check every 25k miles being a very prudent idea. If you don’t torque the bolts correctly – or if they become loose – the spacer can put a tremendous sheer load on the wheel studs.
Excessive sheer loads always lead to failure, and that means wheels falling off at the most inopportune times.
Suspension characteristics change. When you move the wheels further away from the stock wheel hub, you’re effectively giving more leverage to the wheel. On the negative side it means that springs don’t absorb bumps as well, shocks aren’t as effective at damping harshness, and steering requires more effort. On the positive side, wheels that are further apart are more resistant to rollover.
Poor quality is a major concern. If one of the mounting holes on the wheel spacer is slightly out of round, that could allow the entire spacer to wiggle ever so slightly up and down during use. Eventually, this will put all the wheel mounting holes out of round, which in turn will put a large sheer stress on the factory wheel studs…and you know what that means.
Other Areas of Concern
Beware longer studs. While you can buy longer wheel studs, it’s really not a smart idea. Studs have an ideal length to thickness ratio, and longer studs either need to be thicker than the studs they’re replacing, made from a stronger material, or there need to be more of them. Some washer-type wheel spacers will come with extra-long wheel studs, but this is a bad arrangement because the wheel will have more leverage over a longer stud. This could result in a stud bending or snapping, which could cause a wheel to fall off.
Wider tires create additional suspension stress. Every suspension component is effected by wider tires. While there’s definitely something to be gained off-road with a 12.5″ wide tire over a 10.5″ wide tire, it’s important to ask yourself if the increased off-road ability is worth reducing the life of ball and CV joints, wheel bearings, etc. If you’re building an extreme off-road machine, you should be prepared for larger and more frequent suspension repair bills.
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