Question about White Industries MTB hubs

[Tom Sherman]

[email protected] wrote:

> ...
> To reach 63.5 mph, you need extra power or reduced drag,
> either from a tighter tuck, a steeper grade, a tailwind,
> another vehicle to draft, or a heavier rider....

Other (non UCI legal) alternatives include substantially reducing
frontal area, such as a recumbent with a highly reclined seat and bottom
bracket higher than the seat, or substantially reducing the coefficient
of drag by partially or fully fairing the bicycle.

> Pedalling is generally held to be counter-productive at such
> speeds with ordinary bicycle frames and gearing. At 63.5 mph
> with a 2124mm 700c tire and 53x11 gearing, you must spin up
> to 162 rpm before the chain engages the rear wheel--such
> furious pedalling is likely to add more drag than any useful
> propulsion....

The additional drag can be demonstrated by coasting on a long slope, and
then either pedaling backwards at a normal cadence or pedaling forwards
at a normal cadence in too low of a gear to provide any power to the
drivewheel. I have done this on a short wheelbase recumbent, and noted a
drop in speed on the order of 10%.

--
Tom Sherman – Quad City Area

 

[Trevor Jeffrey]

[email protected] wrote in message
<[email protected]>...
>
>Plugging in -0.10 for the grade, 0 watts for no pedalling,
>and 0.950 for air density around 2600 meters produces a
>terminal speed for the other defaults such as 165 lbs of
>riders and bike of 24.4 meters per second, or 54.5 mph

pedalling 180rpm+(3 revs / second) hands together, chin on bars, knees
together with feet level, aero brake levers, aero pedals, aero rims aero
chainset 20mm section tyres +light tailwind <10mph
Apart from corners, never considered coasting down a hill back then. Brake
or power.

>
>To reach 63.5 mph, you need extra power or reduced drag,
>either from a tighter tuck, a steeper grade, a tailwind,
>another vehicle to draft, or a heavier rider.
>
>Pedalling is generally held to be counter-productive at such
>speeds with ordinary bicycle frames and gearing. At 63.5 mph
>with a 2124mm 700c tire and 53x11 gearing, you must spin up
>to 162 rpm before the chain engages the rear wheel--such
>furious pedalling is likely to add more drag than any useful
>propulsion.
>
>For example, a 102 kg bike and rider (214 pounds), will
>coast up to 63.5 mph on the hypothetical 10% grade with the
>0.950 air density.
>
>Or the default 165 lb rider could simply tilt the road to a
>grade of 13.4% at that altitude.
>
>As an overweight Shetland pony, if not a modest Clydesdale,
>even I could presumably roll my 110 kg carcass and bicycle
>down your 10% grade at 66 mph (assuming that it's nice and
>straight and uncrowded and long enough), so your
>high-altitude claim of 63.5 mph seems quite plausible.
>
>Drop it down to sea level air density and my 66 mph drops to
>58 mph.
>
>It should be remembered that many high speed claims may be
>made quite honestly by riders unaware of handsome tail winds
>or the advantage of 40 pounds of baggage. My best speed
>coasting down my daily hill is 15 mph higher than usual, a
>tribute to a fine west wind, while my regular victories over
>a friend in coasting contests down the same hill rely on my
>extra fifteen pounds of ballast, much like any underhanded
>soapbox derby triumph.
>
>Carl Fogel