Full-cone seat vs. Part-cone seat

The “seat” of wheel spacers refers to the contact area between the base of the lug studs/nuts fastener head and the wheel spacers fastener pocket. Although most wheel spacers’ fastener pocket is conical design, there are variations that exist. But mainly in two styles: full-cone seat and part cone seat. In a brief word, full-cone seat is a proven upgrade of part-cone seat.
Full-cone seat design which is the same 60-degree angle and contact area proportion as most BMW OEM wheels fastener pocket, provides larger contact area, more force acreage and better fitting. In that case, the axle-spacer-wheel connection can be fastened firmly, meaning no vibration, fewer stress loads, higher safety and longer service life range. Part-cone seat type is designed with half cone. The greatest benefit is cost-saving. That is why most low-price spacers come with such design. Compared to full-cone seat design, it offers a smaller contact area, less force acreage, not fit enough, more likely to deform the lug studs/nuts by road impact, resulting in vibrations.
The axle-spacer-wheel fastener is the critical connection among the vehicle hub, spacers and wheels. Without proper fastening, there is a risk of disaster. Using the full-cone seat style of fastener for the wheel spacer installation work can not only bring better installing experience but also more particularly guarantee safety.

Side Knurled Design

Knurling is a finishing procedure used to create any combination of horizontal, vertical, or crossing lines on the surface of components. BONOSS applied such process for enhancing both the exterior and function of wheel spacers. For decorative reasons, knurling can enhance the aesthetics of the wheel spacers by introducing an attractive pattern to the side surface. In addition to aesthetics, there are practical features. Knurling patterns can enlarge the side area so that it can contact more air, boost the heat dissipation effect, and also reduce internal stress. That means improving the performance, strength and durability of the spacers.

Dismounting Grooves Design

Dismounting grooves means the small notches which are distributed on the corner of wheel spacers. It is designed to easily dismount the spacers, improving user experience. Normally, it leaves a limited clearance between the axle plate and spacer, using a screwdriver can easily remove the spacers, simple and efficient. If there is no such groove, the spacer will snug the vehicle hub, by forces effect, it can be difficult to dismount. Even worse, you may destroy the spacers or axle hub. Furthermore, the grooves can act as air collecting funnel, which is effectively increasing airflow, enhancing the heat dissipation effect.


A company’s logo is the face of its business. Each BONOSS product is printed with the logo of “BONOSS”. It is a product identity, meaning confidence and responsibility in the quality of our products. This also offers an easy method to distinguish other fake and inferior products. At the same time, it also provides a way to find our after-sales service. Our products are 10 Years Limited Warranty (new products 12 months warranty), which is an excellent and cost-effective choice for your car upgrades.