12/26/2023 0 Comments Onyx vesper hub![]() ![]() The axle size determines the friction torque from the bearings.The reality is the seal and choice of grease will have more effect. The bearing material (ceramic or steel) is often credited with lowering the friction in a hubset.A loose cup and cone bearing allows for fairly slack manufacturing tolerances. A cup and cone bearing will always have more friction than a radial bearing because of an axially oriented contact angle. A cup and cone bearing is a type of angular contact bearing. A notable exception are Shimano and some Campagnolo/Fulcrum wheels which use cup and cone bearings. The vast majority of hubs use 6000 series ball bearings which are deep groove. The most obvious is the choice of bearing type.There are a several engineering considerations to be made when designing hubs which have been discussed below Rotational drag is not the same as frictional drag which comes from the mechanical components. This loss is a significant aerodynamic loss of about 25 to 30 percent. The term rotational drag has been used of late to describe the amount of power required to spin a wheel up to speed. ![]() The total amount of friction is small but a cost effective marginal gain. The remaining friction is from the pedal bearings, bottom bracket and pulley wheels. Wheel hubs and freehubs account for around 60% of the rotational friction in a bicycle drivetrain. As an example, the power differential between wheels of an equivalent depth at speeds of less than 35km/h will only be 1-2W, the difference in bearing friction can easily exceed that. The aerodynamic performance of wheels often grabs the headlines and the marketing budget but the reality is the hubs and the bearings within them will have more of a performance differential for the average cyclist. ![]()
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