BONOSS Active Cooling Forged Hub-Centric Wheel Spacers
Source Factory | Multi-Stage Hubcentric | Customized/OEM/ODM Available
TÜV Rheinland Certified Forged AL6061-T6 ISO Grade 12.9 Studs 10 Years Warranty
BONOSS Manufactured Hub-Centric Wheel Spacers are precision-engineered components designed to optimize vehicle wheel fitment, increase brake caliper clearance, and improve cornering stability without compromising structural alignment. Manufactured from forged aircraft-grade aluminum alloy and machined using high-precision CNC processes, each spacer guarantees accurate centering on the factory hub. Tailored for exact vehicle applications, BONOSS wheel spacers correct wheel offset, prevent tire-to-suspension rubbing, and achieve a wider, aggressive vehicle stance while maintaining complete mechanical safety standards.
Technical Specifications Wheel Spacer Quantity 4 Pcs (2 Pairs) Thickness 25mm (1" inch) Bolt Pattern / PCD 5x112 Hub Center Bore 66.5mm Lug BOLT Thread Pitch M14x1.5 Spacer Material Forged Aluminum 6061-T6 Bolt Material & Grade SCM440 Alloy / ISO Grade 12.9 INSERtED NUT Material & Grade 40Cr / ISO Grade 10 LUG BOLT Seat Type & HEX Cone Seat / 19mm HEX Safety Certifications TÜV Test Reports Verified Vehicle Compatibility
Fits Models: Compatible with Audi 4MN Q8/ SQ8/ E-tron 2018+, Audi B9/B10 A4/ S4/ RS4 2019-2026, Audi F5 A5/S5/RS5 2016+, Audi C7 A6/S6/RS6/A6 Allroad 2011-2018, Audi D5 A8/S8 2018+, Audi FY Q5/SQ5 2017+, Audi 4M Q7/SQ7 2015+; Mercedes Ben A B C E S R CL CLA CLS GL GLK GLE GLK ML SL SLK SLS Class; Porsche Macan 2014-2023, and more. Please verify your vehicle make, model, year, and fender gap clearance before purchasing.
Key Engineering Highlights
- Forged AL6061-T6 Aircraft-Grade Aluminum:
Tensile Strength ≥310 MPa, offering superior resistance against stress and deformation compared to cheap cast alternatives. - Active Cooling & Knurling Surface:
Heat dissipation pattern boosts surface area contact with air, lowering thermal stress during intense driving. - Multi-Stage Hubcentric Design:
Precision-machined to ensure a perfect snug fit on the wheel hub, eliminating high-speed vibrations. - ISO Grade 12.9 High-Strength Bolts:
“BONOSS engraved”, Made of SCM440 alloy steel with tensile strength ≥1282 MPa(ISO 989-1), tested up to 2,000,000 stress cycles. - ISO Grade 10 Inserted Lug Nuts:
Proof load ≥ 1110Mpa, hardness (HV) ≥ 349… Each BONOSS lug nut is “BONOSS engraved”, meaning these lug nuts are made by BONOSS’s factory, the quality is guaranteed. - 10-Year Worry-Free Warranty:
Direct factory backing with comprehensive customer technical support.
Product Knowledge & Engineering Principles What Are Wheel Spacers?
Wheel spacers are precision-engineered disc components placed between a vehicle's axle hub and the wheel mounting face. Their primary mechanical function is to push the wheels outward relative to the vehicle body, effectively reducing wheel offset. This structural adjustment increases track width, creates vital clearance for aftermarket big brake kits or suspension coilovers, and improves vehicle stability during high-speed cornering by lowering the lateral weight transfer index.
How does the BONOSS Active Cooling Technique actually work?
As a professional wheel spacers designer and manufacturer, BONOSS created the Global Pioneer Active Cooling Technique, breaking the single functionality of the traditional wheel spacers. The special petal shape grooves utilize the rotation of the spacers to allow the external cold air to enter and continuously flowing inside the spacers, enhancing the heat dissipation of the braking system. The symmetrical design allows for multiple grooves to work at the same time, no matter it is on the left or right wheel, whether driving forward or reversing, the purpose of heat dissipation can be normally and effectively achieved. Install BONOSS active cooling wheel spacers helps improve the heat dissipation of the brake system, reducing brake fade while providing the functions of traditional spacers.
Why Choose Hub-Centric Wheel Spacers?
Hubcentric spacers offer a better system of support and stability. They are designed to make a snug connection between the wheel and vehicle hub, reducing the high-speed vibration. Based on traditional hubcentric spacers, BONOSS has optimized this design to further reducing the chance of high-speed vibration, it is called multi-stage hubcentric design. According to the actual test, the effect of BONOSS multi-stage hubcentric wheel spacers is far better than the common alternatives, which fit more perfectly, safer, and more stable.
Real Engineering Experience & Fitment Verification
- Caliper Clearance: e.g. During internal fitment testing on the car, 25mm spacer increased front brake caliper clearance by approximately 25mm, enabling full clearance for aftermarket big brake upgrades.
- Engineering Experience: During development, every BONOSS wheel spacer is first measured on the original factory hub.
Product & Fitment Visuals How to Measure Clearance / Spacer Thickness BONOSS Forged Active Cooling Wheel Spacer Kit 12.9 Grade Wheel Studs Precision CNC Backside & Multi-Stage Hubcentric Hub Ring Forged AL6061-T6 Aluminum Material & Hard Anodized Coating Choose BONOSS for Superior Safety, Precision, and Global Trust There are an increasing number of installation examples Material Science & Structural Metallurgy Why Forged 6061-T6 Aluminum Alloy?
(Tensile Strength 310 MPa, Yield Strength 275 MPa, Failure Elongation 8-10%)
Grain Structure Optimization
Hot-forging aligns the continuous aluminum grain flow along the structural contour of the spacer, eliminating internal void pockets common in cast aluminum products.
Forged 6061-T6 vs. Cast Aluminum
Forged 6061-T6: High structural density, higher fatigue resistance, superior yield strength under cyclic load.
Cast Aluminum: Brittle grain structure, susceptible to hidden void porosity, higher risk of sudden impact failure.
Thermal & Corrosion Resistance
T6 solution heat treatment paired with artificial aging optimizes alloy toughness, making it highly stable under extreme thermal cycles from brake rotors.
Manufacturing Process Flow 1. Hydraulic Forging→ 2. T6 Heat Treatment→ 3. CNC drilling machine→ 4. CNC lathe (processing production)→ 5. Deburring→ 6. Hard Anodizing→ 7. Laser Engraving→ 8. CMM Inspection→ 9. Packaging Quality Control & Verification Standards
Every BONOSS wheel spacer undergoes rigorous quality assurance inspections before factory release:
- Tested using plug gauges to ensure strict tolerance compliance (±0.02mm).
- Evaluated for anodizing depth, surface smoothness, and uniform coloration.
Installation Guide Procedure
- Remove wheel bolts and wheel.
- Place BONOSS Spacer on axle of vehicle (where the wheel was attached) making sure that the spacer is fully seated and flush with the hub.
- Fasten BONOSS spacer to car using attached special bolts. Carefully hand turn bolts making sure that they spin in easily so as to not cross-thread. Repeat with the rest of bolts.
- With hand wrench, snug up the bolts in a star.
- Tighten the wheel bolts in a star pattern using torque wrench set to factory specification.
- Ensure no bolt heads come out spacer.
- Place the wheel onto the spacer and carefully form up the wheel / spacer bolt holes and mounting hole.
- Carefully hand turn wheel bolts and make sure that they spin in easily so as to not cross-thread.
- Repeat step 8 with the rest of bolts.
- With hand wrench, snug up the bolts in a star pattern.
- Before fully tightening, turn the wheel and tire to check whether there have any noise or interference.
- Use a torque wrench specified by the manufacturer to snug up the lug nuts in a star pattern.
⚠️ Safety & Technical Compliance Notice
Professional installation by a certified mechanic is strongly recommended.
Always use a calibrated torque wrench to verify fastener torque.
Never stack multiple wheel spacers on a single wheel hub.
Ensure minimum thread engagement (at least 6–8 full turns of thread engagement).
Frequently Asked Questions 1. What do BONOSS wheel spacers do? Wheel spacers push the wheels outward from the vehicle hub, increasing track width, improving cornering stability, correcting wheel offset, and providing extra clearance for large brake calipers or aftermarket suspension components. 2. What are the benefits of installing BONOSS wheel spacers? Wheel spacers are made to create the desired space between the vehicle hub and wheels. Your car become more stable as the wheel spacers provide additional width for the wheel track. With the improvement of the traction, the resistance to rollover as well as the comfort level of handling the vehicle improves a lot. The appearance gets a boost with the wheels flush with the fender line. They are also an instant and cost-effective solution to add custom wheels or big brake kits on your car In addition, BONOSS wheel spacers apply optimized “Hollow Carved” design, which provide obviously lightweight effect, 20% off comparing with the previous production. It is a proven design that is effectively reducing weight, reducing energy consumption, improving control performance, and achieving a balance between high performance and environmental protection on the premise of ensuring safety and reliability. 3. What’s the performance of the matching bolts and nuts of BONOSS wheel spacers? The matching wheel bolts of spacers applied high-strength JIS SCM440 steel material. Take the matching wheel bolts as an example, it has achieved ISO standard grade 12.9, tensile strength≥1,220Mpa, limited life range test≥2,000,000 stress cycles without damage, ultimate tensile load≥152,000N, hardness (HV)≥395, NSS≥500H… And the matching lug nuts have achieved ISO standard grade 10, proof load≥1110Mpa, hardness (HV)≥349… Many competitors often use other brands of studs and nuts in pursuit of lowering the cost, and these studs and lug nuts are often only marked with metric units without brand engraved. In view of this, each BONOSS wheel stud or lug nut is “BONOSS engraved”, meaning these matching wheel studs and lug nuts are made by BONOSS’s own factory, the quality is guaranteed, customers’ interests are protected, and BONOSS takes the quality responsibility. 4. How does knurling design work on the BONOSS 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, boosting the heat dissipation effect, reducing internal stress and also reducing the weight of spacer. That means improving the performance, strength, and durability of the spacers. BONOSS aims to provide wheel spacers for the car with more additional functions, safer, higher performance, more professional design, and better installing experience. BONOSS independent design department insists on professional manufacturing and continuous optimization of the design. 5. Why choose BONOSS Multi-Stage Hubcentric Wheel Spacers? Hubcentric spacers offer a better system of support and stability. They are designed to make a snug connection between the wheel and vehicle hub, reducing the high-speed vibration. Based on traditional hubcentric spacers, BONOSS has optimized this design to further reducing the chance of high-speed vibration, it is called multi-stage hubcentric design. According to the actual test, the effect of BONOSS multi-stage hubcentric wheel spacers is far better than the common alternatives, which fit more perfectly, safer, and more stable. 6. Are BONOSS wheel spacers safe for daily and track driving? Wheel spacers have existed for multiple decades, and there is very little opportunity for wheel spacers failure. They have always been used widely, even within the highest level of racing events. As long as you use high-quality spacers and install them properly, they are just as safe as normal wheel changing. Just as your wheels, tires, and brake mods, only good products can ensure driving safety. The quality and safety are often depended on the design, materials, performance, and manufacturing process. BONOSS wheel spacers are designed with actual measurement, using forged AL6061-T6 material (tensile strength ≥ 310Mpa), and extended with ISO standard grade 12.9 wheel bolts/studs and ISO standard grade 10 lug nuts, and over 66 TÜV test reports certificated. Precision at 0.02mm tolerance, which offers high surface quality, more importantly, safer and more professional. 7. How do I choose the correct spacer thickness for my vehicle? Place a straight edge ruler flat against the outer tire/wheel rim and measure the distance to the inner edge of the fender. Select a spacer thickness slightly less than this gap to achieve a flush stance without tire rubbing. 8. Are hub-centric wheel spacers better than universal non-hubcentric spacers? Yes. Hub-centric spacers transfer the vehicle weight directly to the axle hub rather than relying on the lug studs. This precise alignment eliminates rotational vibration and ensures complete safety. 9. Will wheel spacers cause steering wheel vibration? Properly installed hub-centric wheel spacers with exact center bore matching will not cause steering wheel vibrations. Vibrations occur only when using loose-fitting non-hubcentric universal spacers. 10. How do the wheel spacers affect handling? Wheel spacers bring your car rims and tires outwards, increasing the distance between the left wheel and the right wheel. And most track racing cars would make use of every millimeter of the wheel-wells space available in their design for the highest performance and the best exteriors. A wider wheel track means better traction, hence increasing body control experience, offering better corner performance, and more stable driving. With the car spacers, you can fill the gap in your car fenders and get a more aggressive and powerful look. Finishing with 0.02mm tolerance, BONOSS wheel spacers fit more perfectly to the wheel hub, which means reducing high-speed vibration, offering a smoother driving experience. 11. Are BONOSS wheel spacers safe for high-performance driving? Yes. BONOSS forged wheel spacers are manufactured from aircraft-grade AL6061-T6 aluminum with tensile strength ≥ 310 MPa. Combined with SCM440 alloy steel lug bolts rated at ISO Grade 12.9 (tensile strength ≥ 1,282 MPa), BONOSS spacers exceed strict OEM safety thresholds and have successfully passed over 66 TÜV Rheinland lab tests. 12. What is the significance of the "BONOSS Engraved" marking on lug bolts/studs? Unlike third-party generic bolts, each BONOSS extended wheel bolt is directly produced in-house and laser-engraved with the BONOSS trademark. This ensures complete metallurgical traceability, ISO 12.9 compliance, 2,000,000-cycle fatigue resistance, and full manufacturer warranty coverage. 13. Why Full-Cone Seat Holes? – The BONOSS Advantage. Full-cone seat design provides larger contact area, more force acreage and better fitting. 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. 14. What is the function of BONOSS's disassembly grooves? Disassembly grooves means the small notches which are distributed on the corner of BONOSS truck 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. 15. What is the recommended torque specification?
- M12 Thread: 113 Nm (83.3 ft-lbs)
- M14 Thread: 140 Nm (103.5 ft-lbs)
- 1/2-20 Thread: 130 Nm (95.8 ft-lbs)
BONOSS Brand Story
BONOSS is dedicated strictly to Wheel Fitment Engineering rather than mass-market generic auto parts manufacturing. Founded on the principle that wheel alignment and track width adjustments require absolute metallurgical precision, BONOSS combines material science, advanced CNC manufacturing, and continuous safety testing. Every product is developed to resolve real-world wheel fitment challenges while preserving the highest standards of automotive safety and dynamic performance.
Shipping & Warranty Terms
Shipping: Orders processed prior to ship 1-3 business day via DHL, FedEx, or UPS express service and so on with tracking provided.
Returns: 30-day return window available. Items must be in uninstalled, original condition.
Warranty: 10-Year Limited Manufacturer Warranty backing against structural material defects.
Why Trust BONOSS? 18+ Years Expertise
Specialized exclusively in high-end forged wheel components and custom hardware.
10-Year Warranty
Longest in the industry, with expert support included, 3000+ Measurements, CNC 0.02mm Machining
Safety Proven
Verified through rigorous fatigue tests (>2,000,000 cycles) and tensile tests, over 66 TÜV test reports.
Semantic Keywords Integrated: Wheel Spacer | Hub-Centric Spacer | Forged Wheel Spacer | 7075-T6/6061-T6 Spacer | Brake Clearance | Wheel Offset | Flush Fitment | Track Width | Aftermarket Wheels | Wheel Fitment Engineering | Vehicle Stability | Center Bore | Bolt Pattern | PCD | Offset Correction
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