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Notes from the Bikelab

Issue #9 -- 4/21/91

by Steven K. Roberts

Copyright (C) 2000 by Steven K. Roberts. All Rights Reserved.


Late Night Maunderings
Chaos and the Pedaling Emulator
Bike tech
General Progress Report
Another Midnight Attack

Soft chains are the most difficult to break:
affection, ease.
The spirit, wide-eyed, limp-muscled, nestles
on its side
and waits....

-- graffiti on SF Muni bus

3:15 AM. It's becoming a familiar time -- a favorite one,
even. This time of day, there are few commercials on the radio
to disrupt the back-to-back jams. There are no phone calls,
few stray beeps from the Sparc, none of that constant
temptation to invoke Aladdin to check GEnie or browse America
Online. The time is mine; the only hint of other life is the
occasional passage of a sleepy guard making the rounds or the
clatter of a night janitor emptying trash. (They must
wonder... passing my locked door in the middle of the night,
hearing cranked music of every genre, the growl/whirr/whine of
Cecil/Makita/Dremel followed by the roar of the Great Sucking
Monster whisking deadly aluminum chips from equipment bays...
what's that guy DO in there? He never leaves!)

Occasionally I do leave, of course. Silicon Valley by day is a
frenetic zoo, a place of angry traffic, clutter, stress, and
crowds. Sometimes I have no choice: I drag my entire body
around the city just to acquire a $6.00 part, a process of
dubious efficiency. But by night, it's a different world out
there... quiet and laid-back. I do my food shopping,
gassing-up, and wallet-refilling after midnight, skulking
through the darkness with the graveyard shift, breezing through
intersections that would have me grumbling by day, strolling
across El Camino while hearing only silence.

Tonight there are no errands. I've been extending the power
bus from the trailer, through the hitch, into a small RUMP
sub-panel, and up to a distribution area in the main RUMP bay.
It's now only one more hop to the console, and then things will
start to flicker to life. Perhaps that's why I'm working late
-- this is an exciting epoch in the creation of a system (much
more so than the endless acquisition and repackaging of
isolated components, marathon list-editing, and timeless
staring into space as vaporous n-dimensional images of BEHEMOTH
evolve in the wetware CAD system -- virtual revision levels
incrementing furiously as a massive hierarchical file structure
becomes at once reassuringly structured and hopelessly

The only thing that makes this entire project tolerable is the
fact that it's a PROJECT, not a job. That ethic began in grade
school, when I noticed the vast behavioral gulf between science
fair projects and homework. The latter was irrelevant noise,
busy work involving neither invention nor creativity. Why
bother? The same tasks had already been done thousands of
times by others, and would doubtless be repeated more or less
identically by thousands more. They obviously didn't need ME
to go through it all again. But science fairs! Every year,
the pressure would build relentlessly as I slaved in my
basement lab building acoustic speech synthesizers, pre-CCD
speech compressors, servo-linked harmonographs, diode-matrix-
based Morse code translators... whatever outpourings of 60's
technopassion happened to enchant me at the time. Each was
unique, an obsession, lovingly crafted on a tight deadline and
then documented at the last possible minute (just like in
industry) -- and those 7 annual marathons had more to do with
passion and curiosity than fear of tests.

Those were formative years, so it's no surprise that I've spent
the last 20 doing everything possible to avoid employment. It
has begun to occur to me that this whole bike system -- all 8
years of it from chrome-moly frame to ethernet, from tire pump
to satcomm, from sponsor deals to teeth-clenching mountain
grades -- is just a colossal science fair project, thoroughly
laced with romance, adventure, and the sweet mad essence of
life itself...

Chaos and the Pedaling Emulator

In this issue's emailbag, we have this food for thought from Mike:

I know that in most Sun farms, the order in which things reboot
after, say, a power failure can be critical. If this guy's
yellow pages aren't up yet, the main file server will get stuck
listening to that guy over there, who can't boot without the
right yellow pages, and so forth and so on. This has to do
with, I suspect, an as-yet-unexplored offshoot of the science
of dynamical systems, aka chaos theory (a subject I'm studying
in some detail 'cause I'm geyser-mad and I want to model geyser
eruptions with chaos theory). The point is that when you have
lots of computers busily interdepending, you can have
"pseudo-chaotic" operational configurations, which are stable,
but broken.

Sooooo... just wondering, mind you... are you sure that the
happily operational configuration of SPARC, PC, Mac, and Forth
engines is the ONLY possible configuration, and one which will
be reached every time things come up? Just a thought.

-- Mike O'Brien

Yikes. A useful warning... thanks!

-- Steve

And I thought you might
enjoy this twist in BEHEMOTH's design contributed by Digital Equipment

As part of a non-competitive joint venture with Sun
Microsystems and other software and hardware vendors, Digital
Equipment will contribute a key ingredient to Steven Roberts'
BikeLab. Still under development, BEHEMOTH has been
described as a cornucopia of high tech gadgetry on wheels. The
bike is being prepared by Roberts for the summer riding season
in a lab donated by Sun Microsystems. Since he will certainly
be kept busy on his trip attending to hardware and software
issues, Digital's contribution will allow him to offload the
effort of propelling his bike onto a pedaling emulator.

The device involves a mechanical device that emulates the human
pedaling motion. The pedal will be driven by a metal arm-like
device that in turn is powered by a cylinder sliding up and
down in a tube. During the power stroke the cylinder will be
forced down by the explosion of some sort of combustible
material that must be refilled with each rotation. Digital
engineers are confident that Roberts will be able to find
plentiful supplies of fuel on his trip.

Bike tech

Oh yes. That reminds me. There... IS a bicycle somewhere
underneath all that stuff, isn't there? Often I forget that
and end up with nasty surprises, like trashed bearings and
stretched chains, startled and betrayed by real-world
mechanical wear when I'm thinking digitally. For most of those
16,000 miles I pedaled around with the same parts I acquired
back in 1983, some of which were old even then. Hard-core
bikies would occasionally sneer at my antique Campy high-flange
front hub, and I grew quite tired of replacing headsets every
few hundred miles.

Well, things are changing. With 350 pounds (I, um, HOPE that's
all there is) of cargo, some of the component decisions are
critical. With the help of bike wiz Greg Davis, machinists
Dave Berkstresser and Ron Covell, and the bicycle industry
itself, I've been re-doing BEHEMOTH from the frame up. Let's
take a mechanical tour, starting at the front...

The front wheel is a 16 x 1-3/8 alloy rim with 36 holes, custom
made by Weinmann for the Avatar recumbents about 10 years ago.
The new hub, currently under construction, is a custom
variable-reluctance motor-generator assembly spinning on SKF
sealed bearings... more on that when it becomes a reality. A
Mathauser single-cylinder hydraulic rim brake is mounted on the
Ishawata fork crown, and brazed to this crown is a 1/4-20 stud
that holds a teflon-lined rod end for the steering linkage.
The headset is a sealed Chris King unit -- the latest and
hopefully the final iteration in my endless quest for one that
can take the abuse of heavy equipment. This headset has a good
reputation among the hard-core mountain bikers (and I've also
shock-mounted the new console to filter out high-frequency
impulse energy).

Moving back, we come to the crankset. From 1983 until last
week, this has been a 185-mm TA tandem crank, with a single
drive chainring on the left side. Now it's a custom
chrome-moly 191-mm crankset made by CQP, with sealed bearings
installed in the original eccentric that once allowed me to
adjust for chain-length variations on the tandem-style 1:1
crossover drive. Attached to the cranks is a pair of Cycle
Binding pedals, whose floating heads lock into a very well
designed shoe system. Unfortunately, the company went out of
business before I could hit the road... but the product seems
to be excellent and I guess I'll find a new vendor when these
eventually wear out.

The transmission is perhaps the most striking mechanical
feature of BEHEMOTH (at least until the landing gear assembly
is built -- details in a future issue). It has 105 speeds,
ranging from a killer granny gear of 7.87 inches to a robust
tall gear of 122. This is accomplished via three derailleurs:
a rear unit hacked on the the port-side crossover drive
assembly in addition to a more-or-less conventional 21-speed
indexed system on the starboard side. The gears are:

You can think of the gear chart as a 3-D matrix of 5x3x7 cells,
calculating any ratio as (D/X)*(F/R)*27. Incidentally, a
couple of those gears involved a bit of trickery: the 5-speed
crossover cluster is built on a modified Shimano crankset (arms
removed and lathe-turned to point symmetry). The top three
rings are on the 110 mm bolt circle with some special spacers,
and the other two -- aided by a "Quad Tamer" -- are on the 74
mm circle. Likewise, the triple had a bit of help -- that
19-tooth ultra-granny is mounted on a Limbo Spider that allows
the use of a standard steel cog in place of the usual inner
chainring. The spindle that connects them obviously is longer
than usual -- it's another custom job from Gary Cook at CQP,
142 mm long.

Incidentally, I am often asked why so many gears. A 105-speed
bike? Isn't this a bit excessive, in addition to being harder
to say than "18-speed"? Not at all -- this not only provides a
stunning granny gear of less than 8 inches (1.4 mph at a
cadence of 60 RPM -- now you know why the landing gear), but
also gives me enough easily addressable ratios to allow a good
impedance match between body and bike under any load
conditions. That's important when the whole mess, body
included, is well over a quarter ton...

Derailleur choices are based on construction quality,
integration with the selected shifters, and availability. I do
not yet have any road time with this component suite, so it is
not meant to be a recommendation. At the moment, we have a
Shimano Deore half-step front derailleur, a SunTour XC Pro on
the rear, and an older SunTour wide-range unit on the crossover
transfer assembly. I'm experimenting with the new Grip Shift
from SRAM for the main two, and a pair of classic SunTour
Barcons mounted in the forward seat tubes for the crossover and
the drag brake. Chains are Sedisport ATB on the left and
SunTour XC Pro on the right.

The rear hub is a double-threaded Phil Wood tandem unit, with
48 holes. 14-gauge DT stainless spokes connect it to the
Weinmann concave alloy rim in cross-4 symmetrical UNDISHED
pattern. I can recommend this highly... my undished 48-spoke
wheels have taken 16,000 miles of heavy abuse without ever
breaking a spoke. The only damage I've ever had with this
configuration occurred in Whiteville, NC, when a pickup-truck
door materialized in my path and somehow drove the derailleur
into the spokes, forming a highly-effective one-shot braking
device that contributed significantly to the suite of bike and
body ills that suddenly manifested themseves. (While
recovering from back and leg injuries and waiting for parts
shipments in Whiteville, by the way, I wrote a gripping story
called "Blood in the Spokes." It observed, at one point, that
"I am out spokin' at times... rolling from a wheel-truing deal
to true wheeling-dealing, toiling at truth while reeling from
the raw deal of a rear wheel's real ruin...")

The trailer wheels are 36-hole Suzue sealed hubs with butted
stainless spokes to 20" Sun Chinook rims (whatever those are)
and Haro slick tires. The bike's rear tire has historically
been a Specialized 1-3/8 Expedition, which they discontinued
and then apparently re-introduced (if the lastest Nashbar is
any guide). I'm considering others, including the lively
Michelin Hi-Lites and something Greg is recommending. The
front tire is whatever I can get -- not much quality rubber
exists for 16" wheels. Kid's sidewalk bike tires from Western
Auto typically last 1,500 miles, but it would be nice to
optimize rolling resistance et al with something made for the
"serious" bike market.

In the braking department, I have a pair of Mathauser
hydraulics -- single-cylinder on the front, double on the
rear. There has always been either an Araya drum or Phil Wood
disk on the rear... I'm dissatisfied with both for various
reasons and am looking into a custom motorcycle-style hydraulic
to use as a drag brake and wet-weather insurance. There's also
the regenerative system under computer control, of course --
the first line of stopping defense -- and I'm hoping to add a
pair of brakes to the trailer as well. The problem is that I
have only so much grip strength, and ganging brakes on the
levers actually has a negative effect on stopping power due to
additive power-transfer losses. This calls for some other
energy storage device, which translates into either a surge
system (tricky design but interesting) or a linkage that
captures the force imparted to another brake in order to
actuate the next two down the line. Later.

Finally, the frames. The bike frame is a work of art, a
supremely reliable and elegant custom job by Jack Trumbull of
Franklin Frames in Columbus, OH. The steering geometry is
perfect, which is to say almost "dead," with no tendency to
oversteer like so many commercial recumbents. It has about
1/2" of positive trail. Naturally, it's 4130 Cr-Mo. A thick
tandem-style heavy-wall bottom tube and triple stays contribute
to overall stiffness and resistance to overload fracture.

The trailer frame geometry is defined by the original Equinox
trailer that formed a template for this unit. I tossed the
original upper structure of aluminum and fabric and built the
cardboard-fiberglass body... then noticed that the original
frame was now too fragile for the application. Paul Sadoff of
Rock Lobster Cycles built a beautiful new one of heavy 4130,
and now, if I had the strength, I could probably haul Cecil the
900-pound milling machine without frame failure. But I won't.
This obsession with having it all has gone quite far enough!

Jeez. No wonder this is all a shock. Looking back over the
foregoing, I realize how little attention I've paid to
bike-tech until recently -- it's easy to treat the bike itself
as a chassis and focus all attention on the whiz-bang gizmology
layered atop it. Problem is, failures of bike components can
leave me stranded or worse, so this time money is no object and
I'm depending on help from bike-savvy experts in the business.
It's starting to show...

General Progress Report

In other news, the cable harness is now to the point where the
battery management and raw power distribution span bike and
trailer. The only hard part here was dealing with the fact
that the two units can be disconnected. With the batteries
nominally treated as one big unit, unplugging is no problem...
but what happens if I leave the trailer charging in a sunny
campsite and go for a ride with the SPARCstation running Frame
via Ethernet to MacX? I come back with a low bike battery,
plug in, and ZAP! A hundred amps flows for a few milliseconds,
popping breakers and burning connector pins. The solution,
suggested by Glenn Glassner, is elegantly simple: a monster
iron-core toroid in the inter-battery bus slows down this
initial surge enough to contain it within the parameters of my
protection hardware. Disconnect, which would normally draw an
arc from the collapsing field, is no problem -- the batteries
will always be at the same level by the time I unplug.

Much of the lab work lately has involved the Ethernet and the
things that connect to it. I've been collecting the interfaces
and software necessary to make Mac, DOS, and SPARC enviroments
happy with each other -- apparently a non-trivial task. I'll
report more when things come to life and I know enough to
describe the unix-related components to this predominantly
internet-resident audience without getting flamed for not
knowing what I'm talking about. Fortunately, I'm here at Sun,
so there is no shortage of unix, sendmail, NFS, X, TCP/IP, POP,
and SBUS wizardry in the neighborhood. Latest: the IPC has
been brought up by Ron Lee and Kevin Long, and should be
installed as BEHEMOTH on the network this week to give bike
developers easy access to the tools distributed around the
net. And John Noerenberg at Qualcomm is working on
modifications to Eudora, a public-domain mail program for the
Mac, to handle the human interface end of the OmniTRACS
satellite email link.

Those new packs mentioned in the last issue have been installed
on the RUMP, softening the otherwise industrial appearance of
the machine. (Oh yeah... PACKS! It's a touring bike!) The
new seat fabric is on, supported by 1/8" stainless welding rod
donated by Madco and about 80 Panduit black cable ties. And
Dave Berkstresser's freehand midnight milling madness has
yielded a sort of art deco seat-and-steering assembly. This
was done at the last minute to make the bike ridable for last
week's photo session with Discover Magazine:

Another Midnight Attack

The first midnight attack was the subject of a story in
Nomadness last year, relating a wild inter-cultural adventure
on a cold windswept beach in Humboldt County. The latest
occured last week.

Discover Magazine is doing a story on all this, scheduled for
the July issue -- coincident with my departure. Chris the
photographer (and his assistant) drove up from Santa Barbara to
do the all-day shoot for the 4-page color spread, and Maggie
pedaled down from the Santa Cruz mountains to lend a hand.

It went well all day -- studio shots against a giant white
backdrop hung from the roof of Sun's building 4 (sort of the
back-forty of the Mountain View campus, largely unoccupied and
open at the moment). After a few hours of grinning on demand
and generally looking high-tech, I took the bike outside for
the obligatory afternoon-light shots on the waterfront. That
went well also, except for the mechanical failure of revision 1
of the BYP mounting system <sigh>.

At 9PM we started the big setup. In the dark lawn next to the
building, we hung a giant parachute from a pair of volleyball
poles. The smoke machine was warmed up, and the photographer
and his assistant spent a couple of hours experimenting with
radio-synched strobes (green for the smoke, blue for the bike,
warm for my face). We plugged the bike's HeNe laser into the
trailer's 2500-volt power supply and taped it to a tripod,
aimed at my head. Quiet on the set...

With the assistant generating clouds of smoke and the laser
reflecting from a tiny mirror attached to my helmet (shades of
the Borg), Chris went to work. Security guards stopped to
watch the strange spectacle: blazing multicolored strobes
illuminating thick smoke, a red laser beam knifing through the
haze from my already bizarre helmet, tripods everywhere, a
dew-sodden parachute billowing behind us. We looked like a Yes

Suddenly... we were attacked by the Sprinkler System from
Hell! With a mighty, wet WHOOSH, the ground all around us
erupted in showers of water, sending people scurrying in all
directions, cursing, shouting, trying to rescue thousands of
dollars in photo equipment while not tripping over cables and
shrubbery. I had my own problems: with a yell I took off
across the lawn, still blinded by lights, pushing the bike over
accursed fountains in search of someplace dry. I slowly became
aware of a security guard jogging along behind me with a tripod
under his arm, and remembered the laser. Oops.

It turned out that I had towed the tripod via the Uniphase
laser head, ripping the high-voltage cable from the
unserviceable assembly, and the guard was trying to help.
Fortunately, no sparks flew... and the photo session was
mercifully ended. So was the life of my laser.

And you thought this fame 'n glory biz was easy.....

12.5 weeks and counting. Maggie, my erstwhile traveling
companion, pedals north May 1 with Ryan recumbent bicycle,
trailer, Daylab portable darkroom, laptop, solar panel, 2-meter
Icom HT, and Venus Biscuit Snow (the cat). She'll stop at the
Kinetic Sculpture Race in Eureka over Memorial Day, then will
be in Alaska by the time I truck BEHEMOTH off to Omaha to start
RAGBRAI. Already we're talking of a winter rendezvous in
New Mexico. When the relationships of nomads evolve, the
implications can be bizarre...

One last note: HELP! I need a smart gofer, preferably someone
young enough to not cost a fortune and excited enough about
technology to view this as a bonanza for its own sake. I'll
also pay somewhere between $5 and $10 an hour, depending on the
person and skills. The list of clearly-defined tasks is
growing, and includes holding things, chasing around the valley
for stuff, doing database entry, organizing inventory, keeping
me motivated when I slip into the wall-staring phase of
engineering, filing technical literature, answering the phone,
helping with fabrication, shipping packages, cleaning up, and
filtering out background noise from the universe. Before I
soak up lots of time with a personnel quest, I thought I'd
check with you. Know anyone quick witted and interesting who
is available RIGHT NOW for part-time help, at least partially
during business hours, for the next 3 months? In my youth, I
would have jumped on an opportunity like this... there will be
contacts galore for someone who can use them.

Back to the massive TO-DO list. Cheers from the Bikelab!