SON 28 is a generally approved hub dynamo for all wheel sizes up to 700c (29"). On a 28"-wheel nominal output is reached at about 16 km/h (SONdelux at 19 km/h). SON 28 is recommended when more light is required at low speed or when other devices are to be operated or their batteries recharged. Compared to the SONdelux, the appearance is similar but the flanges are more widely spaced by 12mm and the bearings by 10 mm. Disc brake versions are available with 6-hole or Shimano's Center Lock rotor mounting system. Compared to SON 28 klassik (manufactured from 2000 to 2011) no-load losses were reduced by about 15 % and weight by 140 g.
Electric Power: 6V / 3W according to German government's road traffic regulations (StVZO)
German Mark of Conformity: ~~~ K 834 for 16" 29"
Efficiency: 65% at 15 km/h in 700c-wheel
No-Load Power Input: 0,5 W at 15 km/h in 700c-wheel
Magnets: neodym iron boron, 26 poles
Connection: 4,8 mm flat spades, 2-pin to connect without ground connection (special design without connectors)
Axle: hollow axle Ø 10 mm, strain-hardened stainless steel, (Center Lock rotor mounting system licenses by Shimano: aluminium 7075 T6)
Bearings: deep groove ball bearing 629 2RSH (SKF)
Hub Shell: aluminium 6082 T6
Colors: silver polished, anodized silver, black or red
Sealing: alloy dust shields, rubber lip seals and pressure compensation system
Spoke Drillings: 28 (only ISO 6-bolt), 32, 36
40, 48 (tandem version with a larger flange)
Weight: 440 g (ISO 6-bolt: 460 g, Center Lock rotor mounting system licenses by Shimano: 430 g)