Friday, July 25, 2014

Bicycle bodywork (4 of 4), bike fairings

In Bicycle bodywork part 3, I ended with the 2014 Porsche 919 LeMans Prototype Hybrid Electric:

Drawing credit: Porsche, from article in Excellence, May 2014
It turns out this design has over 2000 hours in a wind tunnel tweaking the airflow.  Aside from steeper leading surfaces and more gradually sloped trailing surfaces, it is not the 1930's classical smooth teardrop shape, it is discrete sections where the airflow is shaped piece by piece for different requirements along the car.  Because of their odd shapes, I think the same methodology can also be applied to cargo bikes.
Photo credit: Porsche, from article in Excellence, May 2014
From the front it is easy to see the fenders are just big enough to cover the tires (no turning the tires sharply!), the cockpit is just enough for the driver, and instead of fairing in a smooth bodywork between the two, the body has been dropped down to just cover the suspension links.  The emphasis is on minimizing the frontal area, and smooth, continuous, streamlined shapes are secondary.  Streamlining works best in laminar air, not so well in traffic or off axis gusts, while minimal area works all the time.
Distance record bike Overzealous with rider Jeff Nielsen, Photo credit: Trisled
Note minimal frontal area.

It is relatively easy to cover smaller bicycles such as Velomobiles and human speed record vehicles in smooth, full bodywork, and it is highly effective at their traveling speeds of 20 to 80 mph.  Cargo bikes are much harder to fair in, but they ignore aerodynamics at their own loss.  If you only ride from 4 mph (walking) to 10 mph (medium run), then you can discount air resistance and go for fat tires to reduce rolling loss instead, but air starts to make a difference when you go above 12 mph.  Since my Bakfiet's average speed was 14.9 mph last summer and the Longtail's about 17-19 mph so far, with maximum speeds on both around 40 mph, aerodynamics is important.  I'd also like to develop a layout that will use the solar panels to provide some basic weather protection.  Taller bodywork, (such as Cedric Lynch's bike and the Velerique shown in my first Bicycle bodywork post), do reduce air turbulence loss while allowing a rider to sit more upright than a recumbent and carry a small load, but 2x4's, surfboards, child seats, etc. will not fit, and it is much more susceptible to cross wind effects.  One solution to load capacity and crosswinds is to make the bike into a Velerique with three wheels:

Twike, original body with human power + electric on left, and newer TW4XP all electric at right.
Photo credit: Foro Coches Electricos
Note that the human powered Twike has motorcycle tires, and the TW4XP has car tires- load capacity and rolling resistance will be roughly proportional to tire size (working air pressure, tread design and compound, and carcase construction also come into play).  The base 10 Ah x 384 Volt battery pack in the original Twike is good for 75 km, or 82 Wh per mile.    Using the Wh/m consumption figures to indicate relative drag/rolling resistance, this is 6.2 times as much energy use as my solar electric Bakfiets at 13.2 Wh/m, which I have found is okay to pedal on level flats, but I prefer to use the electric drive going up hills.  The new Longtail seems to be using about 16-18 Wh/m average, and I can pedal it along a flat up to about 1/3 mile, and then the drag starts to be a little bit tiring and I use the motor.  You probably won't pedal the Twike very far without turning on the motor, (see The Hyper-Efficient TWIKE Human-Electric Hybrid Vehicle, Treehugger for a review), and this means it's range is the battery range.  I haven't found performance figures for the TW4XP, but it was designed for the Progressive Insurance Automotive X Prize which had a contest minimum requirement of 100 mpg, or maximum energy use of 330 Watt hours per mile, and it does not have pedals. My estimate is 2 to 2.5 times the energy use of the original Twike, or 160 to 200 Wh/m.  These levels of energy use will not work well with mobile solar, or for people pedaling with limited physical capacity.

Scaling back to two wheels, the Technische Universität München did a  Mobilität neu erleben mit dem Reisefahrrad Läufer (New mobility experience with a rotor pedal bicycle) project:
Photo credit:  Unternehmer TUM GmbH
Fabric side skirts can be fitted for water protection.

Treehugger also photoshopped the front clip of a Honda Civic onto a Giant Revive Spirit electric assist bicycle:
Photo credit: Treehugger, 2005
Nice fit of the hood over the front wheel, but headroom might be a little tight.

Another version of a streamlined body on a bicycle.
Also known as "A woman needs a man like a fish needs a bicycle." (Irina Dunn)
Photo credit: The MPG of a Human, Tech News 

Fish position, Photo credit: Unknown

Since it is so hard to package a practical fairing onto a cargo bike, let's look at riding position. My upright Bakfiets is almost straight up and down, like an Oma (Dutch for Grandmother) bike.  This is very comfortable and has great vision, but is not good for aerodynamics.  Leaning forward for racing reduces frontal area, and adds the use of gravity to a good leg angle for pushing, but it is hard on the neck, arms, wrists, and back of riders who may have arthritis or injuries, and the seat height isn't good for stop signs.  Moving the seat backwards and down also reduces frontal area, lowers center of gravity, and is a comfortable natural chair posture that allows both feet to be flat on the ground at stops, with the disadvantage of not being as effective for power production up hills.  If the bike is designed with an electric assist in mind, power becomes less of an issue.
Cruiser style, Malmo, Sweden.  Photo credit: Olaf Lundgren

I've had over a dozen people tell me they could not test ride the Bakfiets because they were not able to sit on a bicycle seat.  The narrow bicycle seat necessary to fit between the thighs for a forward leaning bike leg angle would also be uncomfortable for most riders over longer distances.  However as the leg angle from crank to seat is leaned backwards the rear part of the seat can be made wider for better hip support without interfering with leg movement, with the extreme example being the sling seats used on recumbents.  I also know from motorcycle experience years ago that there are many shorter people, mostly women, who prefer the lower Honda Rebel 250/450 motorcycle seat height over a regular motorcycle seat.  RANS calls their bicycle version of this Crank Forward, other bike makers have named them Feet Forward, and there is the historical term SofaCycle.
RANS Hammertruck, Photo credit: RANS
Notice the wider rear portion of the seat, and also the
stub seat post so that a standard front shifting mechanism can be used.
If laid out well it is still possible to stand up on the pedals for hills.

In the last four bikes with the seats moved backwards, you can see a space opens up under the seat where some narrow profile electric mid drive components could fit.  It should also be possible to put a bit of the third bike's mid cargo box under the seat, so that the length could be shortened.  However if the cargo box is large it doesn't package as tightly:
Peter Gibbs, The Jobbing Gardener, with his 8 Freight cargo bike
from race bike designer Mike Burrows.  Photo credit:  8 Freight
Notice the steep head tube angle on this bike- is it for speeding up the
response of a long bike?  Another part of this design is that both the
front and rear wheels attach on only one side.

Adelaide "Ho Chi Minh" Longbike, by Ian Grayson and Bruce Steer, 1988
Photo credit unknown.  The length of this bike is similar to an Xtracycle,
(one rear chainstay, or about 15", longer), and the whole fits together very nicely.
However both the 8 Freight and this bike use standard upright leg angles,
and have either a pronounced forward lean position or full air resistance.

There are two levels of fairings that I am thinking about. The first is bolt on, and I'm starting with a windshield on the Longtail, and then getting a little more sophisticated with a better windshield and lowered seat on the mid drive third bike.  The second level is more comprehensive, fitting solar panels as permanent bodywork, or "solar panel over my head" on the fourth bike, and will offer more weather protection.  Unfortunately this will probably require more of a recumbent leg angle from crank to seat, and I'll test some of the layout on the third bike.  Some examples of bolt on devices are:

Front fairing for a Longtail, by Zzipper.  Photo credit: Thomas David Kehoe
This type of fairing should be positioned about belly height when you are in a semi
upright position, so that it diverts air away from the pocket formed by your body.
It should be as close as possible to your body, while still allowing you to 
lean forward and tuck in behind it for coasting down hills.

A nicely done canopy by Metrofiets, diverting air from the rider's belly area,
protecting hands and lower extremities from cold air, and keeping the load dry.
All corners could be smoother.  Photo credit: Unknown, probably Portland area.

Another Bakfiets canopy, on a Harry vs Larry Bullitt.  Photo credit: Unknown
A BMW K100 sport fairing style curved top.  I would guess that the box is big
because there was a specific load it was designed to carry.  A side comment-
it is good to have rounded shapes and corners not just for smoother air flow,
but also for safety.  Automakers got rid of sharp mirrors and door handles inside
and out, and on other bodywork in the 1970's, to reduce pedestrian and other
injuries during accidents.  Even a small radius helps.

The bolt on aerodynamic aids above will still allow cargo loads.  They are all leading surfaces, as I think that on a cargo bike the air flow is guaranteed to be turbulent, and a trailing edge device will have limited effectiveness.  They will offer some cold air protection, but only a little water protection.  The next step up would be a semi enclosed bodywork, halfway between a regular bike and a velomobile.  Several of the bikes on The Sun Trip during the summer of 2013 used solar panels as a canopy overhead, including several recumbents, however most were not particularly aerodynamic, and some of them probably had a poor reaction to crosswind gusts.

Lionelle Candelle with 300 watts of Enecom solar panels forming a canopy
over a Bullitt cargo bike.  He was running a 250 watt Ludo Technologie mid drive motor,
but the wind was probably stronger sometimes.  The canopy actually cracked
from flexing due to lack of bracing, and had to be welded back together
in Ukraine, but it did finish the trip to Astana.  Photo credit:  The Sun Trip

Team Declic Eco, Angélique and Guillame used a solar canopy and front fairing.
Most of the bikes on this trip were using 250 watt motors because of legal limits
for many countries, and were set up as mid drives to get around the limited power
in mountains.  This bike used a direct drive front hub, and finished about the
middle in a field of 2 dozen bikes.  Photo credit: The Sun Trip

The Velomobile of Josselin Bonmartel, with about 350 watts of solar panels that can
be tilted.  This bike didn't finish the tour, which was just as well as I think some of the
roads across the steppes would have trashed the body.  Photo credit: The Sun Trip

For comparison with the above semi enclosed bikes, the bike that covered
The Sun Trip's 7500 km the quickest and arrived in Astana, Kazakhstan first 
was Raf Van Hulle's Bilenky (or Hase Pino?) framed front cargo bike and trailer.
Notice the minimal frontal area.  Four solar panels were spread out at stops,
and then the 2 removable panels snapped over the 2 fixed panels for traveling.
I estimate these are about 125 watt panels, for a total of 250 watts moving, or 500 parked.
The front panel could be angled left to right.  Raf used a direct drive rear hub motor.
Photo credit: The Sun Trip

Performance comparisons of the Sun Trip bikes need to be done carefully because of external factors.  For example the direct drive hub motors (but not mid drive kits) could be run above the 250 watt limit if the country allowed it, as most of those motors have insulation good enough for 300 to 500 watts or more.  Then it becomes a question of the motor controller's abilities to change parameters, the battery and panel capacities, and driving strategy:  If the weather forecast calls for a cloudy period during the day, should the beginning speed be slow to save the batteries for the cloudy interval, or should it be fast while the sun is out and then revert to pedaling during the clouds?  What if the cloudy period then turns out better or worse?  It's not a straight forward comparison.

A comparison of the frontal area of my solar electric Bakfiets and an ELF
at the Strolling of the Heifers.  (The Tesla S on the left had too much frontal area
to fit in the picture.)  My Bakfiet's long term average last summer was 13.2 Wh/m
at an average speed of 14.9 mph.  Unfortunately the ELF data hasn't been recorded,
so the best guess of energy use is between 20 to 25 Wh/m at close to the same speed,
which is quite a bit closer to a bike than to the Twike's energy use.  (The Organic Transit
website lists a 14 mile range with no pedaling at 15 mph at 75 F, or 30 mile with pedaling,
for the standard 11.25 Ah x 48 Volt battery.  This works out to 38.6 to 18 Wh /m,
with your guess on the level of pedaling and road grades.)

A more enclosed bike with a solar panel canopy could reduce it's frontal area by moving the seat to the rear to lower it, and then adding another panel over the pedals like a Bilenky style cargo bike rack.  The question for me is how much lowering is possible, without becoming a recumbent and losing some of the cargo carrying ability?  I will do some mock ups to test this with the third bike.

For those of you who can't wait for me figure out the fourth bike's
dimensions, I'll leave you with this option...   Photo credit: Unknown

Monday, July 7, 2014

July 4, 2014 parade and booth

The new solar electric cargo bike Longtail was in the 4th of July parade.  I'm going to post some of the pictures, and then follow up with a few more posts of pictures taken while building it.

The basic frame is a Longtail with a battery box in the center and rack on the back.

The bike with the glassless and frameless solar panel on it.  I've attached it 
temporarily, and am designing a clip-on hinge, so that it can be used as a cover
over cargo bags, and also be removed for carrying people or large packages.

Last year I was also put in with the kids bikes, but I don't like riding with them
because they have more energy and will run me over.  I exercise town energy 
committee privilege and wait for a few other groups to go by, and then start out.
It's OK, as long as I'm in front of the horses.

A young builder thinking about making his own bike!  Photo credit: Peter Allison

A lot more fun than the School Board, and no school budget discussions either.
Photo credit:  Katie Rawson

My Hartland Energy Committee booth before the crowds arrive.  On the left is a poster about cargo bikes and data from the bakfiets last summer.  The center poster is on weatherization, highlighting the current Neighborworks HEAT Squad program and $100 household energy audits.  The right poster is about solar, announcing 3 solar workshops being held by Suncommon at the library (the building in the background), and the Vital Communities Solarize program, a group purchase bulk pricing drive for residential installations.  And of course the bike- either most important, or bait for handing out weatherization info, depending on your point of view...

The first test ride on the Longtail.  Chiho's comment was "that has a lot of power!"
I haven't kept an exact count, but the Bakfiets probably reached 100 test rides
at the Upper Valley Electric Vehicle Forum on May 15, and now I'm ready
to start loaning it out for longer trials while I test the Longtail.

I'm not going to say much more about the Longtail until I've done 10-12 rides to be sure that the numbers are consistent, other than to say the Longtail seems to be a bit faster than the Bakfiets, and also use more power.  The direct drive motor also idled along at a 4 year old's parade walking speed nicely (about 2 mph).  An experiment will have to be holding the speed equal and seeing if the energy use becomes equal.  It is also much different riding at the front, after being way at the back of the Bakfiets for the last year.  In a review of the 8 Freight cargo bike, the tester mentioned a distinct feeling that he was moving sideways when turning, and this bike is similar.  On the Bakfiets it was more like watching the front end pivot around the rear wheel.

Monday, June 23, 2014

Sunday ride data and Zen video

Yesterday I took a Sunday ride on the bakfiets, up to a regional Upper Valley/New Hampshire/Vermont Sierra Club meeting in Hanover.  It was sunny with cool air and fair weather clouds, and the meeting was from 1-5 pm, so the meeting was a great excuse for my first longer ride of this year.  I thought the trip stats from the Cycle Analyst data logger would be interesting to others:

Distance:                 40.75 miles
Elapsed time:           2 hours, 30 min, 5 sec
Average speed:        16.2 mph
Maximum speed:      42.7 mph
Volts, start:              41.6  (this is a 36 volt system)
Volts, end:               39.4
Volts, min:               35.9
Amps, min:              -0.02
Amps, max:              17.08
Energy used:           509.58 Watt hours (13.63 Amp hours)
Watt hours per mile:  12.5  (equivalent to 2640 mpg)

A few notes to help interpret the numbers:
-The Cycle Analyst measures any time the wheels are turning.
-The route was mostly two main roads (Rte 5 and Rte 10), with 6 notable hills that are about 0.6 to 0.75 mile long.  I haven't measured the grade on them like I did for my road, but they could roughly be considered "San Francisco" hills.  My speed is 12-14 mph up the hills, and the maximum speed of 42.7 mph is coasting down one of the hills.
-The CA also lists Amp hours forward (13.646), and Amp hours regen (0.0105).  This bike has a gear drive motor with a slip clutch and cannot do regen, the small amount of back current is from the collapsing magnetic fields in the motor coils when the throttle is turned off.  The longtail being built right now has a direct drive motor and can do regen, and I'm looking forward to comparing the numbers.
-I use the EPA standard of 33 kWh per gallon of gas for conversion to mpg.
-13.64 Amp hours is 68% of battery capacity (20 Ah), so the range works out to 59.8 miles, not counting the solar generation.

Solar contribution:
This is not directly measured yet, and has to be calculated.  I have some shunts to put in the solar wiring, but haven't had the time to install them and go through the process of checking the calibration and then the scaling.  However from testing I know that the plug in battery charger is about 85% efficient, and thus the 509.58 Watt hours recorded by the CA should have taken 599.5 Watt hours to recharge.  But when I plugged in the battery after the trip my Kill A Watt meter recorded only 470 Watt hours during charging.  The difference of 129.5 Watt hours would have been provided by the solar panels, which is 25.4% of propulsion energy, or 21.6% of total energy counting battery charger efficiency losses.

The regen is measured by the CA because it feeds back to the battery through the motor wiring, but the solar generation is a separate set of wires and not measured.  The solar 129.5 Watt hours would have been good for another 10.4 miles of range, but since I didn't travel the extra distance it shows up as a fuller battery at the end of the trip.

All in all it was a fun ride, traffic was very nice, the weather was great.  I've been riding only short 15 mile trips to the center of town once in a while, so the electric assist was a big help.  I wore regular street clothes for the meeting, and my legs are 99% normal after the longer ride.  I'd do it again.


Unrelated to the statistics from the trip, here is an interesting video.  Jack Kerouac (author of On the Road) wrote a letter to his first wife, Edie Parker, about 10 years after their marriage had been annulled, while he was discovering Buddhism.  Film director Sergi Castella and film maker Hector Ferreno made the letter into a short video for Dosnoventa Bikes- We were never born:

WE WERE NEVER BORN from Dosnoventa on Vimeo.

Tuesday, June 17, 2014

Bicycle safety, Round 2

I thought that my earlier blog post about Helmets and Safety would cover bike safety for the purposes of building and testing a few bikes, but safety keeps coming up while I'm out with the cargo bike talking with people, and is proving to be a major issue.  This isn't logical- we associate biking with young kids, but then feel it isn't safe for mature adults.  Safety is turning out to be a long row to hoe, so it seems like I should write down some of the things I've had conversations about.

First, a graph:
(Click on images to enlarge.)

At the beginning of April, Greg Raisman of the Portland (Oregon) Transportation Department gave a talk for Boston Health Associates about the effect of speed on the severity of accidents.  (The second speaker Barry Keppard, Manager of the Boston Metropolitan Area Planning Commission, Public Health Division, talked about the effects of lowering traffic speed, which parallels the efforts of bike advocates in NYC to reduce speed limits on side streets to 20 mph.)  Greg showed a most excellent graph (above) on Fatality Risk versus Collision Speed.  I had struggled with these statistics while writing my Helmet blog post, because I knew that an electric bike was faster, but the best data for estimating the increased risk that I could find were simple bar graphs with only two or three bars- not very good for communicating to others who are thinking about traveling faster on an electric work bike.  Greg's graph is from a presentation that P. Wramborg gave at a road safety conference in Warsaw in 2005.  Looking at the "Pedestrian or Cyclist" curve on the left, the (unprotected) human body does a really good job of surviving a crash up to about running speed (12-15 mph), and then from 20-25 mph the curve becomes a threshold, above which the risk of dying increases very quickly.  When I started this bike project a couple of years ago I had been thinking of 40 mph speeds between towns to make using a bicycle more feasible for errands, but after a year of measuring elapsed times I've realized that the average speed matters as much as top speed.  My car may top out at 50 mph for several miles of my trip to White River, but most of the trip is at slower speeds with stops, and the car's average speed is actually only 26 mph.  A consistent 20 mph on an electric bike would be significant.  I now think these are feasible design speeds for future bikes:
-50 mph- is over the top and becoming a moped
-40 mph- upper limit, since I already reach 42 mph coasting downhill on the bakfiets
-30 mph- electric motor plus strong pedaling, (note that you cannot do this with a pedelec system which turns the motor off above 20 mph.)
-25 mph- I often reach 22-25 mph with moderate pedaling on the bakfiets.
-20 mph- the federal speed limit for bicycle motor assist "when powered solely by a motor, of less than 750 watts (1 h.p.), on a paved level surface with a 170 pound rider" (HR 727 Consumer Product Safety Act, Section 1).
-5 to 15 mph- standard Oma (upright) commuter bike speed, and the speed I ride my bakfiets in closer quarters.
I now like a design goal of 30 mph for the intermittent open stretches of the trip (and downhills) to raise the average speed and increase bike use feasibility, with a 750 watt motor for my steepest hills that I can't ride up right now with 500 watts.  The usual traveling speeds should end up below the greatly increased chance of injury, and it will be legal (remember I hand these bikes off to other people).  FYI- you'll note from the other two curves in the graph that being in a car increases the speed you can survive by about 12 mph for a side impact, and another 12 mph for a head on collision, which is not a lot considering all the safety equipment in a car.

Update added on July 21, 2014:  California does not allow electric assist above 20 mph:
Item 3 of California V C Section 406 states: "Is incapable of further increasing the speed of the device when human power is used to propel the motorized bicycle faster than 20 miles per hour."

A second safety item was a great drawing by Bikeyface:
Bekka Wright of echoes what I tried to make clear in the Helmet blog post.  Helmets don't have magical powers, and there is much, much, more that is more important than a helmet in staying safe on a bike.  You don't put a helmet on inside a car and then expect to be safe if you drive badly.  People who are concerned about biking safety (and pedestrian, child, senior, handicap, and neighborhood safety too) should spend their energy on driver training, awareness, and infrastructure.  Safety is an action that all of us have to put there.

Roads have been a commons through out most of human history, and only in the last 100 years have they become subservient to the automobile.  Cars, light trucks, and buses probably reached 1 billion globally in late 2010 (, but bikes had reached 1 billion globally somewhere a bit before 2000 (  The gap has only gotten wider, as car and bike annual production was about equal up to 1965, but in the last 3 decades there have been twice as many bikes produced as cars, and the trend seems to be growing, (World Watch Earth Policy Institute, see my earlier Helmet and Safety post for a fuller discussion). Bikes by all rights should be getting more infrastructure dollars, but for most countries this has led to public policy arguments and political funding fights instead.

BIKES vs CARS TRAILER from WG Film by Fredrik Gertten. (
"This is not a war.  It's a city.  We should live together in peace."

At an International Transportation Forum in Berlin on June 6, 2011, B.K. Chaturvedi, member of India's Planning Commission told the 800 delegates: "We in India need to provide more roads and rail.  Cycling is a miniscule thing.  That's not the future."  Asian countries expressed the same sentiment for their developing economies, (
Photo credit unknown, probably in Oregon at a festival.
China is accelerating development of Electric Vehicles, but this is still bad news for resource use, congestion, and making real connections.  To me increasing the number of cars is pretty much Planet Down the Tubes material.  This is too big to be my fight, so I'm looking for what I can do here and now.

The Oregon Department of Transportation has released a good study of the effectiveness of bike lanes, Lessons from the Green Lanes: Evaluating Protected Bike Lanes in the U.S. and they find them to be very good for safety and perceived safety (i.e. convincing more people to bike).  This is a good report, and I love the graphics.

Here is a series of 4 very brief videos about changing infrastructure, speed limits, numbers, and the overall health benefits from cycling being 20 times greater than the risk from accidents and air pollution:
"The benefits of cycling outweigh the risks by 20 to 1."
From the  Cycling, Health, and Safety working group report

There isn't enough money to extend infrastructure to all the roads in Vermont and it is a slow process, so I think I have to work with the roads we have.  I do think the infrastructure that we have in urban areas does indirectly benefit rural roads, because auto drivers get reminded there are bikes on the road.  However if VT AOT could fund more bike infrastructure that would be great.

The three foot minimum passing distance rule.  Photo credit: Kent Schram
Education (and repetition, repetition, repetition of it in an engaging way) are needed for all road users about how to interact with each other.  I'm learning about riding for myself, and hope that agencies will spread information to other road users.

My last option is making bikes work better on existing roads.  I admit I am a bit biased towards the bikes I am building, because their capabilities enable me to mesh with traffic flow better than a typical sporting bike.  This can be good (easy for me), or bad (it enables a transportation system built for only cars, and it doesn't do a thing for other bikes).

Did I mention helmets?
A bicycle helmet cannot do this, but it doesn't have to either.
Bicycle speeds are much slower.  Photo credit:  unknown
Commuting on a work bicycle is not the same thing as racing on a high power motorcycle.
This is what commuter biking looks like.  Tram, pedestrians, bikes, and cars.
Photo credit:  Unknown (location probably northern Germany)
More of what bicycling looks like.  Photo credit unknown.
Bicyclists in Europe lined up at a intersection stop.  Photo credit unknown.
Bicycling Without Ages Program, Seniors on a ride, Oslo, Norway.
Dutch biking ad.  Photo credit
Oops sorry, wrong photo.  This is not commuter or work biking.
Photo credit Steven Lloyd Photography
Lane separation using just speed bumps, Germany.  Photo credit unknown.
Regional Director for Mercedes in Ukraine on Bike to Work Day.  Photo credit unknown.
Can you spot the difference between racing and commuting?
Photo credit: unknown
Children Cycling to School, Graph credit: European Cyclists Federation
Why is it that the countries that are most obsessed with bike helmets,
(USA, Canada, Australia, UK), have the least experience with biking?

Last week my friend Charis posted the question: "Does anyone have favorite stats / readings / sources about bike safety?".  A few of the replies were:
One of the most insightful replies was posted by Adonia Lugo related to her transportation equality study, Planning for Diverse Use/rs: Ethnographic Research on Bikes, Bodies, and Public Space in LA:
"Bicycling is legal on city streets in the United States.  No laws keep motorists in their cars.  This is not a situation where people's everyday practices have been disrupted by state apparatuses that govern through direct force, such as military police or an invading national power.  And yet, an estimated 33,885 people died while using streets in the United States in 2009, according to the National Highway Traffic Safety Administration (2010).  Of that number, 4,280 were pedestrians and 618 were cyclists, which means the vast majority of that estimate refers to dead motorists and their passengers.  In the same year, an estimated 2,239,000 people were injured while using surface streets and highways.  Bike advocates frame these injuries and fatalities as a design issue- with street infrastructure designed specifically for cycling in place, fewer people would drive.  Instead of taking the built environment's role for granted, I chose to consider that this might be a case of discipline, the 'internalization of standards that are then enacted through bodily compliance.' (Foucault, 1977)"

I just spent a day as part of the Strolling of the Heifers parade in Brattleboro, and the following (cargo bikes) Bicycle Petting Zoo.  I'm planning on writing a post about the event, but want to mention here that while I was talking to people about bikes during the afternoon, bicycle road safety was the third most common topic, after questions about first- the solar electric cargo bike I was standing next to, and second- the unusual concept of using a bike for work purposes.  (The timing of this post is mainly because of those conversations.)  We are a very car centered culture, and even for those who are willing to try, it is hard to see an option different than cars.  There is a fair amount of uninformed fear, and also overprotective helicopter parent syndrome. The simplest change I'd make about the safety question is to reframe it as the chance of being injured in a car or on a bike, not solely about being injured on a bike, to acknowledge that you can and often do get hurt very badly in a car.  But there are many other larger questions for me about the trade offs we make to be in a car.  There are two other negative habitual internalizations beyond Adonia's "standards that become bodily compliance".  First, we all use our childhood as a reference for the state of the world, so we do not easily see the cumulative changes that cars have done to us, our society, and our environment over a hundred years.  Second, we internalize the power of a car as our own power.  We deny the reality of our bodies, and expect super human capacity to be normal.  Our relationship with our surroundings has become abnormal.  It is part of our psyche to use tools, but it seems like it is time to question our all consuming dependancy on the auto.

After the Bicycle Petting Zoo I had to ride to the other side of Brattleboro, and the best route was through the center (1.4 miles) on downtown roads with continuous parked cars.  With the electric assist on the bakfiets I was able to travel as fast as the cars (25 mph), with the cars accelerating away at the stop lights and then I'd catch up in a couple of hundred feet.  I rode in the regular travel lanes like a motorcycle. (To some extent bikes like this make the need for bike lanes superfluous, but the catch is still taking care of all the other bikes that can't travel this fast.)  The only problem was climbing the uphill out of the center with a one foot wide shoulder before the curbing.  I stayed as far right as I could, but a small sedan behind me at the light just had to pass.  It was pitiful, as he had the accelerator floored and wasn't traveling much faster than me, and then I had to stop and wait for him to turn at the next stop sign.  He had a large error from his car centered view of the world but could not see it, and I had to deal with it.

Cars were truly amazing inventions of human creativity when I was a kid in the 1960's, and I still think some car driving is very special.  But with increasing Vehicle Miles Driven per capita, I have watched them become an appliance, a unit in traffic.  (You are not stuck in traffic, you are traffic.)  I would argue that they have moved beyond the obesity, diabetes, heart disease, pollution, asthma, sprawl and environmental degradation linked to car use, and have now become a retreat from connection with the world around us and our thoughts.  This should be enough reasons to use a car less, but most people will not be able to make a change.

What is risk?  Is the limitation of risk such as envisioned by conservative financial investors and military advisers really applicable to bicycle riding?  Is not walling off part of life a sign of decline?  I'd like to end this post with a bit of philosophy.  As Martha Nussman states about Euripedes' play Hecuba in the second half of this discussion with Bill Moyers, a life without openness, without trust, without risk, is not a human life:
Martha Nussmann, The Fragility of Goodness, interview with Bill Moyers, 1988

"This says something very important about the human condition and ethical life, that it is based on a trust in the uncertain and a willingness to be exposed; it's based on being more like a plant than a jewel, something rather fragile, but whose very particular beauty is inseparable from that fragility."  Wrapping ourselves in a 3000 pound steel cocoon and telling ourselves that we are safe is a deception.  Driving a 40 mile commute everyday at 65 mph is a distortion of reality.  The everyday actions that we take- often just to get by- are what actually creates our world.  How deeply do we wish to live?

Monday, June 9, 2014

Longtail chain stays and battery box support

With the battery box finished, I could measure how long the frame needed to be extended and how high the rack had to be.  Starting at the base of the frame the first pieces were the chain stays.
The battery box measured 17" long, 12 1/2" high, and 4 7/8" wide.  I drew a side view sketch of the outline of the box, the bottom bracket and rear axle locations, seat tube, a back footrest that I think will fit 2 five gallon buckets, and the rack on top, so that I could identify the key conflict points and decide which way to shift the layout around.  It appeared that the chainstays needed to be extended 24 3/8" to fit everything, which is almost twice as long as an Xtracycle extension kit, (but the bike would still be 1.5 feet shorter than my bakfiets).  I kept the small chainstay cross brace in front of the tire for mounting a fender, but also decided to add a stronger cross brace in front of it for the new junction of framing members.  Unfortunately this was too far back for attaching the new rear footrest, so I decided to seal off this tube to make it stronger by sandwiching it in between the chainstay extensions, instead of leaving it open for attaching accessories like on the Xtracycle.

(Click on images to enlarge)
I made a jig to hold all the chain stay extension pieces in alignment.  Starting with a 44" long scrap piece of plywood, I drew a center line and laid out the locations of the supports with a square.  Trimmed blocks (I have a pile of little pieces from other projects) at the right thickness prop the pieces up and locate them side to side and front to back, and then I put some woodworkers glue on them, pressed them in place, and left them overnight to dry.  In this jig the bottom bracket fits in the blocks on the left, a long bolt substitutes for an axle in the slots on the right blocks, and the new extension tube junction is propped up in the center.

I forgot to take a picture of the pieces at this stage, so this is an out of sequence later photo to show how the frame fit in the jig.

This is what actually came out of the jig, at this point it is tack welded together using a MIG welder, anything more would burn the jig up and reduce the accuracy.  I routinely work to 1/32" (0.030"), and often lean cuts in one direction or another that brings accuracy to 1/64" (0.015").  Tighter accuracy than that is problematic as the scales on standard carpenter's measuring tapes vary in size along the tape, so you have to use other methods. However within assemblies such as the chain stay extension above, it is easy to get to 0.005 - 0.010 simply by holding the pieces up and comparing or scribing them.  Wooden jigs also introduce an error, because wood moves with changes in temperature and humidity.  On a small jig like this for a short interval of a few days it isn't a problem, but if I were to build a series of bikes I would make a large jig where a whole frame would lay on it's side, and the jig would noticeably move.  Using a composite material such as MDF helps, but still requires some adjustments on different days.  (Or spend a lot more money and time to make a metal jig.) At any rate this jig is more accurate than the factory was, where the bottom bracket was 3/32" to the left side, the rear wheel tipped 5 degrees to the right, and the bend in the rear seat stays 1/4" different.

If you'd like to read a bit more about handwork and accuracy, David Pye wrote a couple of excellent books a few years back- "The Nature and Art of Workmanship", and "The Nature and Aesthetics of Design".  He built a semi automatic skorp to explore the interaction of humans and machines in guiding tools, and made some beautiful carved dishes to illustrate his thesis.

I lined up the template center line with a line drawn on the (level and flat) floor, and then lined up the front frame section and forks with the floor line.  This lines up the bottom, and to keep the top straight at this stage I used a level on the downtubes, (watch out for tubes of different sizes), and a string from inside the rear dropouts to the head tube.  There isn't much frame at this stage to measure, but it will save a lot of trouble later on if you get this part right.
I use a very fine string.  In another life when I was doing woodworking, Japan Woodworker was selling ink string lines that had a very fine line, (in contrast to the usual carpenter chalk line), and I started using that line with chalk.  Braided fishing line is an acceptable substitute, and for applications like this where I'm measuring and not putting down a line, I've dyed the line a bright color to make it more visible.
Both sides of the seat tube should have the same distance to the strings.  For safety I should mention here that if you cut up your old tape measures for use as high visibility rulers, YOU MUST NIP THE CORNERS OF THE PIECES!  to blunt them.  They are VERY sharp, and will eventually give you a very nasty cut.
The frame needs some triangulation to make it rigid.  Unfortunately the battery box is in the way, so I was able to put only one tube under the box to reduce vertical flexing.  I propped up the pieces and marked out a tube location with some clearance to the front edge of the battery box.  
This tube ties the seat tube and the new chain stay junction together to stop upward movement of the new chain stay extensions.  If this tube were all there was I would not be happy- I think eventually heavy loads on the cargo bike would bend the seat tube.  However the rack and a few other stays further back will share the load to help increase strength, and should make the bike stiff enough to handle decently.
Propping the bike up next to the battery box again, I measured for supports for the battery box, and cut out tabs to put on the brace tube.
Across the top of the tabs is a heavier piece of sheet metal, so that the weight of the battery doesn't deform the floor of the thinner battery box.  After welding this piece on, I was able to finally set the battery box in the frame, check clearances, and mark out holes for the mounting screws.  The two screw mounts in the frame tube are actually bottle holder mounts from when the tube was previously a down tube.  I put them to the side for possible use in mounting a chain guard, or maybe an idler sprocket if the chain droop turns out to be too large.