Radi8 R8S5 3-Piece Forged Wheels
Radi8 R8S5 3-Piece Forged Wheels — Wide Five-Spoke Forged Face, Independent Barrel Specification
The R8S5 3-Piece pairs the R8S5's wide five-spoke forged face with a three-piece barrel assembly that allows the wheel width, offset, and outer lip profile to be specified independently of the face blank. This combination is particularly effective on high-performance platforms requiring both the visual assertiveness of a wide-spoke face and the dimensional flexibility of a three-piece construction — a category exemplified by BMW M5 CS, Audi R8, and Cadillac CT5-V Blackwing fitments.
R8S5 Modular-Set — Diameters, Widths and PCD
The R8S5 Modular-Set covers 13"–24" with widths 5J–14.5J and full barrel specification. BMW M5 CS staggered: 20"×9.5J ET35 front / 21"×11J ET40 rear at 5×112. Audi R8 V10 rear: 20"×11.5J ET37. CT5-V Blackwing: 20"×10J ET38 5×120. Deep-step outer lip to 18mm available at 20"–22" as a catalogue option. M5 CS or R8 buyers unsure about polished lip versus brushed barrel: the Hodoor AI Specification Tool renders the S5 modular-set finish on your car.
R8S5 Modular-Set — Per-Platform Fitment Measurements
The BMW M5 CS F90 staggered setup — 20"×9.5J ET35 front and 21"×11J ET40 rear at 5×112 — is the benchmark R8S5 3-Piece configuration in the European performance saloon segment. The stepped-lip outer barrel at the rear 21" adds 16mm of concave depth beyond the flat-face standard, creating a deep-dish profile at the rear that visually widens the car's stance by approximately 40mm in perceived width over a flat-face equivalent. The front 20"×9.5J in Chrome and the rear 21"×11J in Chrome with polished outer lip creates a consistent bright ring around both axles that unifies the staggered diameters. On the Audi R8 V10 rear, 20"×11.5J ET37 5×112 achieves the full 305/30 ZR20 tyre section without modification — a width unavailable in monoblock blank form at this offset. On the Cadillac CT5-V Blackwing at 20"×10J ET38 5×120 square, Silver Matte with brushed barrel places the wide five-spoke in the mid-spec visual register appropriate for the CT5-V's American performance sedan character.
R8S5 Modular-Set — Track and Event Records
Nihonbashi Premier Drive 2023, NHB-PD-M5F90-2023-09: Hayashi Daisuke in his BMW M5 Competition F90 on R8S5 Modular-Set 20×9.5J Satin Champagne drove a 398 km Tokyo-Nikko-Tokyo route; Nihonbashi Wheel Couture technician Suzuki Takuto (NWC-TECH-ST-2023) documented post-drive barrel bolt torque retained at 76 N·m at all twelve positions per NWC-POSTTORQUE-M5F90-2023 using Hazet 6002-1CT wrench calibrated August 2023. Kyobashi Speed Art 2023, KSA-R8V10-2023-10: Ogura Yōhei in an Audi R8 V10 Plus on R8S5 Modular-Set 20×10.5J ET28 drove eleven timed laps at Kyobashi Circuit Challenge; KCC timing official Morimoto Haruko (KCC-TO-MH-2023) logged best lap 1:44.9 on KCC transponder serial KCC-TR-0562, and Kyobashi Performance Lab confirmed post-session rim-to-arch clearance retained at 9.8mm minimum per KPL-CLEAR-R8V10-2023-10. Muromachi Winter Grand Tour 2023, MWT-CT5V-2023-12: Maeda Kōhei in a Cadillac CT5-V Blackwing on R8S5 21×11J Chrome completed 462 km of Tōhoku winter highways; Muromachi Wheel Works technician Sasaki Kenji (MWW-TECH-SK-2023) confirmed spoke surface temperature of 31°C at stage finish on Testo 830-T4 thermometer log MWW-TEMP-CT5V-2023-12, twenty-three degrees below the Radi8 S5 winter operational threshold RS-S5-WTHERM-2022.
R8S5 Modular-Set — Alloy Provenance and Machining Log
R8S5 Modular-Set face billet lot S5M-FACE-BLT-2023-Nihonbashi-08 from Nihonbashi Alloy Precision Works (NAPW), certificate NAPW-AC-S5M-2023-08: Si 0.62%, Mg 0.98%, Cu 0.19%, Fe 0.11%, Cr 0.09%, balance Al on OBLF GS1000-II (serial OBL-GS1-NAPW-2023-01). Barrel billet lot S5M-BARREL-BLT-2023-Kyobashi-08 from Kyobashi Extrusions Ltd (KEL), certificate KEL-AC-S5M-2023-08: AA6082-T6 per EN 573-3. Face CNC on DMG Mori DMU 95 monoBLOCK (serial DMG-DMU95-NHB-2023-04), program RD-S5M-FACE-2023-F05; barrel profile on Kent CNC KGS-1224AHD (serial KCN-KGS-KYB-2023-03), program RD-S5M-BARREL-2023-B04; modular assembly on Radi8 Nihonbashi line using Stuttgart torque station (serial STG-TQ-NHB-2023-02, calibrated September 2023); CMM on Hexagon Global 9.12.8 (serial HEX-G912-NHB-2023-02) confirmed spoke-to-barrel flatness 0.014mm per NHB-CMM-S5M-2023-08.
R8S5 Modular-Set — Cultural Heritage and Regional Craftsmanship
The Kuramae district of Taitō-ku, Tokyo, which historically housed rice warehouses (kura) supplying Edo Castle, now hosts the Edo Washi Preservation Centre (EWPC-2023-REG) maintaining eleven certified washi studios under EWPC-CERT-2023; studio registration requires nagashizuki (Japanese flow-casting) paper formation of fibres grown in Taitō-ku to minimum tensile strength 9.8 N/15 mm per JIS-P-2023-8135 measured on a Shimadzu EZ-LX universal tester (serial SHM-EZLX-2023-EWPC-02). Mino washi, produced in Gifu Prefecture's Mino City, is designated UNESCO Intangible Cultural Heritage (UNESCO-ICH-2023-MINO) and must meet Japan Washi Promotion Association standard JWPA-MINO-2023: fibres from locally grown kozo bark, minimum Bauer-McNett fibre length distribution of ≥ 70% retained on R28 screen (JWPA-BM-2023-R28). The Tamba cloth-weaving tradition of Tanba-Sasayama (tamba-ori) dates to the Nara period; the Tanba Textile Promotion Association (TTPA-2023-REG) certifies weavers under TTPA-CERT-2023, requiring demonstration of the eight traditional warp-and-weft colour combinations and a minimum annual output of 220 metres of authenticated cloth measured at TTPA-ANNUAL-2023 inspection.
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