BONOSS Forged Active Cooling Hubcentric 5x110 Wheel Spacers for Alfa Romeo Giulia 952 (1)

With spacers for rims, you don’t have to spend a large budget on aftermarket wheels while improving the appearance of your vehicle. Their thicknesses vary from about 1/8″ all the way up to 2″ or more. If you intend to make your car look sportier and more noticeable without changing wheels, then the thickness will be determined by the distance from the edge of the fender to the face of the tire. If it is the offset problems of aftermarket wheels, then you need some calculation. Given an example, the ideal ET is 40. With an ET50 offset rim, you can put in a 10mm spacer to meet fitment. Presuming that you had clearance issues at the brake, you want to add only enough thickness to clear the caliper. Then the thickness depends on the increased height of the caliper. If you are in the process of completing a wide body kit for your car, to get wheels flush the fender, you can add around 1.5-2.7 inches spacers per side.

BONOSS Forged Lightweight Plus Wheel Spacers Slip-on Wheel Spacers ET

There are two main types of spacers for rims that exist on the market: slip-on wheel spacers and bolt-on wheel spacers:

  • Slip-on wheel spacers that slide over your existing wheel hub, they normally thin in size, e.g., 5mm spacer, 10mm spacers, 15mm spacers. If you using this kind of spacers for rims, it is critical to ensure your stock bolts are long enough for the proper thread engagement. At the minimum, thread engagement length must be equal to or greater than the diameter of the fastener. In other words, if the bolt is 14mm in diameter, the nut must engage onto the stud by at least 14mm. If not, you’ll either need to change to thinner car spacers or get longer and stronger wheel bolts installed.
  • Bolt-on wheel spacers (also called rim adapters) are bolted to the existing studs with the provided lug nuts and then using the stock lug nuts to secure the wheel on the new studs pressed into the spacer. This ensures you can fully engage the lug nuts. You don’t have to change to longer wheel studs. Like the slip-on spacers, these will move your wheels out, but they normally come in thicker sizes, e.g., 2-inch wheel spacers, 1-inch wheel spacers, 20mm spacers.

BONOSS Forged Active Cooling Wheel Spacers Bolt-on Wheel Spacers ET

Aluminum 6061-T6 Aluminum 7075-T6
Ultimate Tensile Strength 42000-45000 psi (300-310 Mpa) 74000-78000 psi (510-572 Mpa)
Tensile Yield Strength 35000-40000 psi (241-275 Mpa) 63000-69000 psi (434-503 Mpa)
Fatigue Strength 14000 psi (96 Mpa) 23000 psi (160 Mpa)
Hardness (Brinell) 93 150
Failure Elongation 8-10% 5-11%

Quality means everything in any spacers for rims. While you may consider that a simple and cheap car spacer is “just enough to use”, the fact is, lower quality means lower safety. Never skimp on price and end up with unsafe low-quality spacers. The quality is always a huge deal when it comes to the components you add to your car. In the market, wheel spacers made from aircraft-grade (or higher) aluminum are the basis of quality spacers for rims. When you find a reputable store, you’ll find that they use 6061-T6 or 7075-T6 billet aluminum as the material of spacers. This ensures strength, service range, and safety as well as high resistance to corrosion. If the store you’re buying from can’t confidently say that it uses aircraft-grade 6061-T6 or 7075-T6 billet aluminum, you should probably find the nearest exit. Although, many stores claim that they are selling 6061-T6 aluminum car spacers, but they are not made by the forged process. In fact, they are cheap casting spacers. Forging provides higher performance spacers than casting. It further enhances the hardness and toughness of the spacers. With the same material and cost, the strength and safety of forged spacers are far higher than casting ones.