Coker spokes tied?

[Nathan Hoover]

Has anyone experimented with tying and soldering their Coker spokes? Five of
us were out on a ride Sunday and stopped at a local high end bike shop for a
minor repair. The guys there were great and not only did the work for free,
but gave us a 6-pack of beer while we hung out in their blessedly
air-conditioned shop. They were interested in our cycles, especially
Bronson's Creative Gecko machine and my "Super Coker" wheel.

For $28, they will tie each pair of spokes together with wire and solder
them. They say this will increase stiffness which might be a great option
for those without the Super Coker wheel. I know this used to be somewhat
popular with roadies, but don't know anyone personally who's done it. They
also measured tension in my wheel (80kg) and Bronson's (10kg) and they were
impressed with the Super Coker wheel.

Anyone tried this? A couple of the guys here are thinking of having it done.

---Nathan

PS If you're in the South Bay Area of California (Los Altos specically), go
to Bicycle Outfitter http://www.bicycleoutfitter.com/ for all you cycling
and repair needs! A mighty fine shop.

[U-Turn]

Hey Nathan. I actually considered the tying and soldering operation for
your wheel, but Jobst Brandt has done experiments that demonstrate no
noticeable increase in performance in any sense. Brandt says, "there is
no change in lateral stiffness, torsional stiffness, or strength".

It also makes the spokes, and the wheel in general, significantly less
serviceable. The original reason for tying spokes was for high-wheeled
bicycles; to restrain broken spokes, thus allowing the rider to continue
despite a broken spoke. Those spokes are much much longer than Coker
spokes. That historical reason has perpetuated and morphed into a
popular myth that is unsupported by scientific investigation.

The guys at the shop might investigate having their tensiometer
recalibrated since it probably gets lots of use. Mine is newly
calibrated and I had an average tension of at least 95 kg on your wheel;
unless you have had had the wheel worked on, it should be the same now
as when I sent it out.

That's cool that they liked the wheel and Bronson's Gecko. I'd love to
see that thang in person.


--
U-Turn - Mounting a Revolution

Weep in the dojo... laugh in the battlefield.

'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)

-- Dave Stockton
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[U-Turn]

Nathan, I've been thinking about my reply and realized that it's way
off.

The part about the spoke tying is fine. There is nothing to change
there. What I need to address is the spoke tension issue.

Your average spoke tension when the wheel left my shop was about 175 kg,
Nathan. This is with no tire installed. Installing tube and tire and
inflating the tire to, say, 60 psi, would have dropped the average spoke
tension somewhere around 10 kg as an educated guess, to about 165 kg.

If your wheel is in good shape (i.e., you have had no
spoke/rim-destroying crashes) and no maintenance has been done on it,
then this number will not have changed. On The Strongest Coker Wheel
(actually yours is stronger), after Ryan's 7.5' drop and lots of rides
and trials and the like, the average tension has basically remained
unchanged.

So, again barring misfortune of an extreme kind, I believe your wheel
has the same average tension on it, about 175 kg per spoke with tire
deflated.

How did the bike shop get 80kg? Probably by reading the tensiometer but
not converting the tensiometer reading to kg by using the Calibration
Chart. For example, my Wheelsmith tensiometer reading of "80"
corresponds to 102 kg for a 14g round spoke. For my tensiometer, a
tension of 175 kg reads about "96" on the tensiometer. So, assuming
that their tensiometer has a different calibration chart, and that the
arms on their meter are worn somewhat, and so it needs to be
recalibrated, and that they read the tensiometer reading to you and not
the actual tension in kg, we can see how they would say "80".

If the actual tension is 80kg, there is a serious problem which we need
to address.


Please accept my apologies for the "95kg" that I posted earlier. It was
completely incorrect. It was, in fact, doing the same thing that the
bike shop appears to have done, because 95 is the approximate reading on
my tensiometer for a spoke tension of 175kg.


Does Bronson's wheel have 14g stainless spokes or stock Coker spokes?


--
U-Turn - Mounting a Revolution

Weep in the dojo... laugh in the battlefield.

'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)

-- Dave Stockton
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