98mm Toothless Aluminium Flywheel

Engineered from high-purity aluminium alloy, this toothless flywheel combines light weight (~285g), corrosion resistance, and mechanical reliability. Key dimensions include 98mm outer diameter, 34mm inner diameter, 15mm thickness, and a 4-hole mounting pattern with 57mm adjacent and 81mm diagonal hole centre distances; each hole is 8mm in diameter. It employs metric positive threading and is compatible with 420 and 428 reduction chain sprockets. Its toothless architecture provides uninterrupted rotational freedom during coasting, removing mechanical chatter and wear-inducing engagement forces. The precision-machined profile ensures uniform contact pressure and thermal stability during repeated load cycles — critical for electric trikes operating in stop-start urban traffic or sustained hill climbs. Applicable to standard bicycles, mobility tricycles, electric-assisted trikes, and retrofitted EV platforms — especially valued by UK users seeking dependable, low-maintenance drivetrain components that integrate cleanly into existing assemblies and comply with evolving sustainability expectations.