Specifications of the rear hub:
Brand: Shimano
Model: FH-C501 Nexave
Color: Silver
Number of spoke holes: 36GTS
Type of brake: Disc (6 bolts)
Number of gears: HG Body 35 MM = suitable for old type Race (max 10 speed) and all MTB cassettes.
Type of axle: Drop axle
Axle included: Yes, quick release
Type of bearings: Ball bearings
Average weight (GR): 446
Intended use: MTB - Tour

Data for spoke length calculations using the Sapim spoke size calculator:

Total length of the hub (MM): 135
Non-gear side (MM): 33
Gear side (MM): 41
Hub diameter non-gear side (MM): 61
Hub diameter gear side (MM): 61

Link to spoke calculator: www.sapim.be/spoke-calculator