Reluctantly, because I'm losing business to do so, LiveWire is taking
the position that the Schlumpf hub is too narrow for a 36" wheel. It
would result in a wheel with improper geometry. Although the Airfoil
rim would provide a lot of stiffness, the resulting wheel would not be
properly built, and excessively flexy and weak. It's even marginal for
a 29er wheel. A wheel built with this geometry, with whatever skill,
will tend to rub on brake pads and frames in general use.
By comparison, a Suzue (61mm), Profile (62mm), KH 2005 (67mm), or even
Harper hub (60.3mm) are 60mm+. A rear track hub for a bicycle is on
the order of 63mm (Suzue Promax) - 80mm (Phil Wood).
It's my opinion that 100mm flange-to-flange, like the widened Suzue
(101mm) first pioneered by Chris Reeder and subsequently produced by
GB4, then by Tom Miller, or the UDC Coker hub (100 mm), is the
appropriate width for a 36" wheel for general use. I imagine that I
would also share Pete Perron's position that 80mm is acceptable as well
for general use (hard hill climbs, use of brakes, etc), though I really
do think that 100mm is more suitable. In Pete's 2nd generation case,
his brake is a centrally-located disk brake, which eliminates the issue
of brake rub, and leaves only the issues of frame rub (much less
restrictive) and overall strength (plenty for road use of a geared
unicycle).
If I remember correctly, the stock Coker hub was on the order of 50mm,
and the excellent QU-AX hub is at 55mm, both unacceptable.
This opinion is not the result of lack of experience with larger
wheels, but based on such, and based on the year-long project that
resulted in the prototype Strongest Wheel, still going, er, strong. In
that project, I found that, even when using a wider hub and Airfoil
rim, the rim would rub on the brake pads. Not till I raised the
tension to the highest appropriate for the rim and geometry did that
problem go away.
To have a good wheel, it's not enough to have a properly trued,
uniformly tensioned and highly tensioned wheel based on good
components. It's important to have good geometry as well.
As a result, I'm restricting my own builds with the current Schlumpf
hub to 29ers and below, and feel that the hub is most suited for 26"
and below, given the present flange width. I know that there exist
36's with this exciting new hub, and that people are enjoying them. I
just have to draw the line somewhere.
Similarly, if someone, looking to use the wheel off-road, ordered a 36"
wheel with a Profile hub, which I support wholeheartedly, I would build
it with caveats, but would try to steer him or her towards a KH, which
is wider. A wider Profile or KH would be ideal, but in the quantities
required to get a special order, impossible for LiveWire at the
present, not to mention technical restrictions on axle length and the
like. I would not want to use a Suzue (little justification when the
wider hubs are available) or a Qu-ax (too narrow).
There might be special circumstances that dictate exceptions, such as
for track use only where wheel strength is less important and brakes
are not a consideration.
I know that this position is not universally shared, and I apologize
for any inconvenience that my holding it causes. I look forward to the
next evolution of the promising Schumpf product to see how it
develops.
In the meantime, there are lots of cool projects in the works and to
come. Working with Scott Wallis is a real pleasure and there's lots of
fine riding to do, with great people, here in Texas.
Thanks, Greg, for your words, so pleasing to the eye to read.
--
U-Turn
Weep in the dojo... laugh on the battlefield.
'LiveWire Unicycles' (http://www.livewireunicycles.com)
'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)
'29er Tire Study' (http://u-turn.unicyclist.com/29erTireStudy/)
'New York Unicycle Club' (http://www.newyorkunicycle.com)
-- Dave Stockton
------------------------------------------------------------------------
U-Turn's Profile: http://www.unicyclist.com/profile/691
View this thread: http://www.unicyclist.com/thread/45093
