The best unit to choose is the one that results in the most convenient number. For the weight of a bicycle, you'd probably want to use newtons or pounds. The kilogram, also widely though incorrectly used as a unit of force, might also be convenient.Kilos would work, as would pounds. * * * * Kilos and pounds are OK for mass but mass is not weight. The metric unit for weight is a Newton. The Imperial units would be the pound-force or poundal.