For owners of classic Euro-tuners like the BMW E30 or the VW Golf Cabrio, wheel selection is often the most frustrating part of a build. These legendary cars use a 4×100 bolt pattern, which limits you to a handful of vintage designs. The BONOSS 2X 18mm 4×100 to 5×114.3 Wheel Adapter Spacers solve this problem, acting as a “bridge” that allows you to bolt on modern, aggressive, and widely available 5×114.3 (5×4.5″) wheels.
Product Features
BONOSS is globally recognized for manufacturing high-performance wheel accessories. This adapter set is not just a spacer; it is a precision-engineered conversion kit.
- PCD Conversion: Seamlessly converts your 4-lug (4×100) hub to a 5-lug (5×114.3) pattern.
- Active Cooling Technology: Features unique heat dissipation grooves that allow air to circulate between the hub and the wheel, reducing heat soak on the braking system.
- Forged Aluminum AL6061-T6: Crafted using a forging process that offers significantly higher strength-to-weight ratios compared to cheaper cast alternatives.
- Knurled Surface: Designed with a knurled edge for better grip during installation and a high-tech aesthetic.
Technical Specifications
- Thickness: 18mm (Ideal for achieving a “flush” look without excessive fender rolling).
- Vehicle Bolt Pattern: 4x100mm.
- Wheel Bolt Pattern: 5×114.3mm.
- Center Bore: Hub-centric design specifically for BMW/VW fitment (ensure to check your specific hub size).
- Stud Grade: SCM435 High-Strength Steel (Grade 12.9) with ISO certification.
- Finish: Hard Anodized Black for maximum corrosion and rust resistance.
Pros and Cons
| Pros | Cons |
| Endless Wheel Choices: Opens up thousands of wheel options from brands like JDM-spec BBS, Rays, or Work. | Installation Complexity: Converting from 4-lug to 5-lug requires careful attention to stud clearance. |
| Improved Stance: The 18mm thickness widens the track, improving handling and cornering stability. | Wheel Offset Change: You must calculate your new “effective offset” to avoid rubbing against fenders. |
| Hub-Centric Safety: Reduces vibration by ensuring the wheel is centered by the hub, not just the bolts. | Maintenance: Requires periodic re-torquing of the adapter-to-hub nuts. |
Installation Guide: How to Convert Your Hubs
- Preparation: Jack up the car and remove your 4×100 wheels. Clean the hub surface with a wire brush to remove rust.
- Mount Adapter: Slide the BONOSS adapter onto your 4×100 studs. Use the low-profile nuts provided in the kit to secure the adapter to the hub.
- Torque Check: Torque the adapter nuts to your vehicle’s factory specifications (usually 80-90 ft-lbs) in a star pattern.
- Wheel Mounting: Place your new 5×114.3 wheels onto the adapter’s studs and secure them with standard 5-lug lug nuts.
- Safety First: Re-torque all nuts after the first 50-100 miles of driving to ensure everything has settled correctly.
Why BONOSS for your E30 or Golf?
The BMW E30 and VW Golf Cabrio are icons of the 80s and 90s. When you modify these cars, safety is paramount. Low-quality adapters can crack or cause vibrations at high speeds. BONOSS adapters are forged, meaning the grain structure of the metal is tighter and stronger. At 18mm, these adapters give you the perfect “stance” without requiring extreme body modifications, making them the gold standard for Euro-to-JDM wheel conversions.