Sunday, January 15, 2012

How good are modern bike wheels? 

Another use for cadence and speed computer devices is allowing comparisons between different wheelsets. I recently noticed a short 2 minute video of a Kinetix Pro 20" wheel.  The hubs are made by American Classic and the complete wheel assembled by them from high end components for Dahon and others folding bikes.  Obviously an excellent wheel, but how does it compare to regular 20" aero wheels, or 700cc road bike wheels?

I probably need to road test a Dahon with a set of these wheels on to see truly how it compares, but since no one has shop samples of these machines in the area, tough to do.  In the meantime this simple spin test is an indication of how well the wheel rolls generally.  This is the spin test from 60 mph for the SparCo 451 20" aero wheel, and then the Williams Cycling 30X wheel, with ceramic hub, same approach.

Verdict is that all three wheels seem to be about 80 to 90 seconds spin time on this test.  Which tends to make one think the physics here is the real limit for how smooth and friction free the hub bearings and rachet mechanisms are.  Cheap wheelsets however are in the 60 seconds or less range; I tried a couple of low end Shimano hubs and budget wheel rims also.

All of this is rather moot since of course ride quality, acceleration, weight, effort, power transfer, wind cross section, cornering and myriad of other factors that make a wheel handle well on the road, not shown in this test!

There is actually a ton of very high end science, wind tunnels, computer simulations and more being thrown at wheel development - see also this article on bike wheel and tire science.  Not surprisingly the math and science only has a limited sense of everything that is going on dynamically with a wheel as it moves under different load and wind situations. The difficulty of research can be seen from this link on tire materials and sizes here (see comments at bottom). Traditionally this has all been trial and error development of course, to see what just "feels better" and delivers better more consistent results on the road against the clock and other peoples equipment.  For certain that today's wheels will outperform older equipment simply because of the quality and materials now available.

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