On 20/10/16 05:09,
cycl...@gmail.com wrote:
>
> My comparison is between the top of the line Campy Neuron al wheels
> compared to the older Campy Atlanta wheels.
>
> There are two major differences: 1. The hubs - the Atlanta uses the
> older Campy Record huhs that do now have sealed bearings. and 2. The
> Neurons have aero spokes.
>
> The Atlanta's are noticeably faster and I expect that is because they
> do not have sealed bearings. All of the wheels that I've looked at
> that have sealed bearings ALL run down much faster than the older
> hubs with open bearings.
Losses in cartridge bearing seals, while they may appear significant if
you spin the wheel and estimate based on how it slows, is usually
insignificant in practise.
IIRC, at 50km/h each sealed cartridge bearing in a hub might consume
about 0.5W total, and 0.4W of that is in the seal. If you can notice
the difference of less than a couple of watts (for both wheels), you are
far more sensitive than most.
>
> The aero spokes are NOT a good idea. They are very costly and
> especially on modern wheels with fewer spokes they tend to break more
> often.
>
Actually, aero spokes are not a terrible idea, provided you use enough
of them that the wheel is reliable. The initial cost difference on a
wheel might be $40, but the wheel will be more aerodynamic.
I think the reason the Atlanta wheels feel faster to you is because the
rims are quite aero compared with the Neutron rim.
Atlanta rims are heavy, but once that weight is moving, on the flat at
least, it does not hinder.
Atlanta rims: 590g, 19mm wide x 34mm deep.
Neutron rims: 20mm wide x 18mm deep
--
JS