Wheelset development at AC Schnitzer A few definitions in advance Wheel/complete wheel = rim incl. tyre Wheel set = 4 wheels All-round tyres = same tyre size on the front and the rear axle The wheels have a really important role: they are the postcard-sized connection between the vehicle and the road. They play a key role in the driving and propulsion as well as the deceleration - i.e. braking - of your vehicle. This gives the wheels a key role. Anyone who develops and sells wheels therefore has a great responsibility. We are aware of this responsibility; we have internalized it and implement it with every new development. AC Schnitzer only uses high-quality brand tyres, which are developed in close cooperation with premium tyre manufacturers. On the one hand, the tyres have to transfer the power of the engine perfectly to the road, on the other hand, properties such as braking behaviour, lateral control, water drainage in rain and the properties in straight running are important decision criteria for or against a tyre. A wheel set with wide base tyres is always also an investment in increasing driving safety and dynamics. In order to maintain driving comfort when using larger wheel dimensions, we at AC Schnitzer have actively opted against run-flat tyres and for sporty, conventional tyres. Conventional tires build up less rolling resistance and offer noticeably more comfort. All AC Schnitzer wheel sets are tuned in multi-stage driving tests in traffic and on race tracks. Only after successful test runs the wheels are released for sale. All AC Schnitzer wheel sets are delivered fully assembled and balanced. They are subject to a two-year manufacturer's warranty. The scope of delivery includes mounting materials such as adapters and wheel bolts as well as the homologation certificate (with the exception of marked wheelsets for export). Philosophy/Design Technically modern design combined with a high quality production process, these attributes characterise the AC Schnitzer AC4 Flowforming wheel generation, which is launched in the sizes 8.5J x 20" and 9.5J x 20", in the colour variants BiColor Silver/Black and Black. The circumferential undercut reflects the high technical standard of the AC4 Flowforming rim. This is because this design element can actually only be realised if it is machined out of a solid material, such as is required in the forging process, as it is located behind the spokes. The undercut of the AC4 Flowforming rims is particularly visible on the BiColor version, as it brings out the high-quality aluminium with its silver surface. Material Only high-quality aluminium alloys are used. The material is additionally heat-treated in the production process, which results in higher strength and simultaneous weight reduction. Material samples during the production process guarantee the constant and high quality of the material. Manufacture Due to the production process, the new AC4 Flowforming rims are lighter than conventionally cast alloy rims and this is measurable: the 8.5J x 20" weighs just 11 kg and the 9.5J x 20" rim also weighs only 11.9 kg. The flowforming process is one of the most advanced manufacturing technologies in wheel industry. In this production process, after the actual aluminium casting, the raw product is further processed by rolling it out. This step serves to compress the metal, which guarantees greater stability and impact resistance of the rim. On the other hand, the improved stability also allows the design of the wheels to be more filigree, as the wall thicknesses can be significantly thinner compared to conventionally manufactured rims. Surface BiColor In this process, the wheel is first primed and then completely painted. Now the surfaces, which are later to shine metallically bright, are turned off and then polished to a high gloss. Finally, a two-layer clear coat is applied, consisting of a polyester primer and the acrylic clear coat. Test Procedures / Safety After their design, the first sample rims are manufactured under real production conditions. These must undergo a multitude of tests. Among other things, the strength is tested. The "rim life" is simulated in the bending circumferential test. Every AC Schnitzer rim must withstand this intact in order to be allowed to be produced and sold at all. This is followed by vehicle-specific tests, including test installations with check of unobstructed movement and driving tests on public roads and on race tracks. Only after these procedures our rims receive their homologation, i.e. the approval to be used in road traffic. Wheels are safety-relevant components. Therefore, they are checked and tested with the greatest care. This starts with the first chemical material tests and ends with hard testing machine endurance runs: - § 30 StVZO wheel guideline - ECE R124 - Bending-rotation tests - 90° impact test - unwinding tests Scope of delivery: - 4 complete wheels: 4 rims AC4 Flowforming Silver/Black – mounted and balanced - 4 pieces RDC wheel electronics modules - specific hub cover - homologation certificate - vehicle- and rim-specific mounting and fastening material - 2 years manufacturer's warranty Uniqueness of the wheel set with the AC4 Flowforming Wheels: - weight-optimized - developed exclusively for BMW vehicles - machined original AC Schnitzer logo - open design in BiColor Silver/Black, giving a clear view to the brakes - engineered in Germany - compatible with standard RDC system - also available as a rim without tyre - warranty 2 years - production monitored according to ISO standard - BiColor Silver/Black optionally also in Black - KDS mount for wheel alignment according to BMW specification is available - Spacers/mounting package for the best possible position in the wheel arch (to be ordered separately)