![]() ![]() These have low levels of friction, are well made and use decent quality bearings from the factory. Generally speaking, the Hambini recommended hubset to use would be the Carbon-TI. It is more advisable to wait until the bearings have worn out first and then retrofit. It is not cost effective to replace OE bearings straight from the factory unless the rider requires the ultimate in marginal gains. The power figure has some factors for calculation and it’s advisable to use this as a relative reference rather than an absolute figure.Some of the hubs had completed an unknown mileage, they were checked for vibration to ascertain any bearing fault frequencies.A sample size of one for each hub set does not take into account any natural variation.They do not take into account Road Vibration.These tests results have some limitations The chart below shows the friction loss through hubs which were loaded. Having bearings that are misaligned due to slack jigs and holes that are too tight due to worn cutting tools will severely hamper friction levels. This is a standard process but it can be riddled with quality control issues. Machining accuracy, a lot of hubs are manufactured in Taiwan by forging aluminium 7075 alloy and then machining bearing landings afterwards. ![]() The smaller axles will always have lower frictional torque because the moment lever is shorter, the negative effects are the wheel hub will have more flex and the bearings will not last as long. Axle sizes of between 10mm and 17mm are common on bicycle hubs. 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. ![]() Not sure what’s the difference between XD and XDR Drivers? Head to our News & Tech Section to learn more.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. Onyx Vesper Hook Flange Hubs for Berd Spokes To learn everything there is to know about the innovative Hook Flange design, head to our News & Tech Section! ![]()
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