
From wheel size 400mm(16”) to 535mm(20“):
The 9 series output perfectly matches German StVZO 6V3W/20” regulation. As can be seen from the table, from wheel size 400mm(16”) to 535mm(20”), the 9 series output is designed to meet StVZO regulation.
From wheel size 646mm(26”) to 716mm(28”):
According to German StVZO, it requires 3V output at a low speed of 5km/h. If the 9 series is set on wheel sizes of 646mm(26”) and 716mm(28”), it offers 3V output speed at 5.8km/h and 6.4km/h respectively. To have 3V output, it only needs to slightly increase speed up to 1.4km/h. Furthermore, according to German StVZO 6V3W regulation, it requires 5.7V output at 15km/h. If we set the 9 series on wheel sizes of 646mm(26”) and 716mm(28”), this 9 series offers 5.7V output when speed at 15.7km/h and 17.7 km/h respectively. To have 5.7V output, it only needs to increase speed up to 2.7km/h. As for 6V3W, the German StVZO approved hubs in the current market normally offer 6V3W output when speed around 17km/h. The SP 9 series offers 6V3W output for 646mm(26”) and 716mm(28”) wheels when speed at 16.7km/h and 18.6km/h respectively.