Archive for the ‘Bicycles’ Category

Pedal Power

Pedal-powered electrical generator. Illustration from The Human-Powered Home.

Pedal-powered electrical generator. Illustration from The Human-Powered Home.

Many people who have ever spent much time on a bike have considered the idea that the same system could be used to generate electricity. As far back as 1914, Popular Mechanics was writing articles about bikes adapted to generate power. Today, several companies offer kits that adapt or just connect to a bicycle that allow it to be used as a small scale generator. It would seem like the perfect convergence of efficiency, self-reliance, and simple solutions. Unfortunately, not so fast…Generating power by bike may not be such a great idea after all. The first issue is that humans really aren’t terribly strong. A healthy adult can put out about 100 watts of energy for a reasonable amount of time. That might drive a few light bulbs, but you’re not going to run an air conditioner or charge your new Nission Leaf with that. But if you’re going to ride to exercise anyway, why not capture that energy even if it’s just a small part of your daily usage? Well, because you may not be generating what you think you are.

As we’ve looked at before, one of the real bugbears of generating any type of energy or work is loss in conversion. Every step you take to transform or convert energy from one type to another typically has a pretty big loss. Bike powered generators are no different. First of all, the human body is not a terribly efficient converter itself. We use food to power movement. Transforming the stored chemical energy in our diet to power movement already has huge losses. Once we do start pumping our legs though, we still have to power the bike, converting muscle based movement to mechanical rotation, that rotation then has drive a generator, and then finally, we typically have to store the electricity somehow to allow for future use.

A recent article in Low Tech Magazine does some back of the envelope calculations and arrives at the conclusion that just looking at the losses that occur in the bike itself and the generator, roughly 2/3 of the energy you produce by pedalling is wasted. In looking at the energy and materials needed just to build the kit that converts your bike into a home generating station, the authors finds that you would be unlikely to ever even generate enough power to replace what was used to build the kit in the first place. Not so good. But this is not to say that there is no place for human powered work and specifically pedal power.

The article’s author goes on to explore ways to solve the massive loss built into a bike converted to generation. His first point is that your typical bike is well designed to drive you around, not to spin a generator. Custom built pedal machines designed specifically to drive a generator can remove most of the major mechanical inefficiencies in a standard bicycle. But as we’ve seen, anytime you convert energy, you have losses, so he points to one of the best improvements, take the electricity completely out of the equation.

Pedal Powered Machines work by using the pedalling force to directly drive work instead of generating electricity that is then used to perform work. Think of the foot powered sewing machine or potter’s wheel as two of the few versions of this technique that really survive today. Human powered machines go as far back as anitquity. But pedal powered machines really didn’t come into being until the 1870’s when the invention of the bicycle spurred other uses for the highly efficient foot powered design. (Ironically, it was only the arrival of the fossil fuel powered industrial age that allowed for more advanced steel manufacturing that made pedal powered machines possible.) The combination of using the most powerful muscles in the legs, with a compact design, with the ability to properly gear the movement made pedal power vastly superior to other human powered devices for most applications. The late 19th and early 20th centuries saw an explosion in pedal powered devices for home and industrial use that only died out as fossil fuels and electricity slowly became cheap and ubiquitous.

Other than a few niche and novelty attempts to bring back pedal powered machines like the Fender Blender, not much has been made of the advantages of pedal powered machines in the industrialized world in recent times. But there are those for whom the unique combination of efficiency, low-cost/simple design, and freedom from industrial energy has real advantages. Groups like Maya Pedal and others have developed pedal powered machines that are cheap, effective, and perform critical work in a developing world environment. Most of these machines are designed for basic farming tasks, water pumping, light weight industrial or manufacturing work and the like. The combination of greatly amplifying the body’s strength without being dependent on unavailable, unreliable, or unsustainable power sources make these machines ideal solutions for the tasks at hand.

So while mini devices to charge your iPod while you ride may be handy ways to harness your legs, think before you build that home generator system and instead look at making a pedal powered washing machine instead.


Who’s Faster?

The car versus bike race has been done many times. Usually in a dense urban area with the bike squeaking out a win. But here’s a new twist too good not to post:

In honor of Los Angeles’ Carmegaddon (the closure of a section of freeway for one weekend for construction), Jet Blue airlines is offering flights between Burbank and Long Beach (roughly 40 miles). LA’s Wolfpack Hustle challenged them to a race, and to Jet Blue’s credit, they took the challenge. Door to door, bike vs. jet. My money’s on the bike…

(hat tip to LA Streetsblog)

Bike Shops in Berlin

It took me a little while to find some really interesting shops in Berlin and I keep running across odd little ones by accident. Since I couldn’t find a good online (English) list of shops in the city, I thought I’d post what I’ve come across so far. The list is NOT comprehensive and tends to focus on Kreuzberg and surrounding areas. Also, if you just need a good, general new bike shop, they’re everywhere so I won’t bother to comment. But these are some of the more interesting, focused shops I’ve run in to. I will continue to update the list as I make discoveries.

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Vacuum Cleaner Advocacy

BikePortland has a recent post about a talk given by Copenhagenize’s  Mikael Colville-Andersen. He’s touring the US promoting urban cycling. He makes an interesting point about the difference in approach to cycling in Denmark. In Copenhagen he says, “Our relationship to the bicycle is much like the vacuum cleaner. We don’t have five of them that we keep polished and well-oiled, there are no vacuum cleaner enthusiasts… The bicycle and the vacuum cleaner are just tools. One of them we clean our homes with, the other we use to transport ourselves around the city.”

This is something I noticed immediately in Germany. Arriving to find cyclists everywhere, I assumed I’d find a huge, thriving ‘bike culture’. In fact, it appears to be the opposite. There is not that strong of a sub-culture of cyclists because they’ve been absorbed into the culture at large. Sub-cultures don’t tend to stay distinct when your mom, grandma, and little sister also do the same activity. In the US, most cyclists view their riding as part of their identity, an activity that defines them. At least among the middle class who don’t ride purely for financial reasons. The shared identity as cyclists binds groups that otherwise have little in common. What will happen to these sub-cultures as their advocacy slowly changes cycling from a fringe activity into just another tool.

Colville-Andersen says that this is not just an outgrowth of increased cycling, but also a key approach to take when planning cycling infrastructure. “Enthusiasts” will go out of their way to do an activity, no one else will. Infrastructure needs to be built where people are and linking the places they want to go.

Efficient Flow

TrafficThe main justification of the drop bar riding position is that it is “faster”. This of course is correct in terms of aerodynamics, power output, and the like. What it doesn’t take in to account is the environment you are riding in. For urban riding, what is the fastest? When you’re the lone biker on a busy street full of cars, speed is usually your friend. I believe it is safer to have less of a difference between your speed and that of the cars around you. Since lights are timed for fast moving cars, you are also more likely to move through intersections if you are closer to automotive speeds. The flip side of riding hard though is time spent before and after the ride. Special shoes, secure your pants leg, maybe even a full outfit change? After the ride comes the cool down period before you’re ready to reenter polite society. Like many a car I’ve seen gunning the gas, just to hit that red light, I wonder if we sometimes mistake max velocity for speed. Door to door, what really gets us there faster?

In Berlin, I’ve seen this affect amplified. Nearly everyone seems to trudge along at an easy 8-10 mph pace. Pleasant enough, but it feels painfully slow for someone used to revving up the heart rate on every ride. But I quickly notice the housewife I passed in a flurry 2 blocks back catching up to me at the next light…and then again after my normal cruising pace sends me past her once we start moving again. Why am I breathing harder than she is when we’re covering the same distance in the same time?

In this town, what seems leisurely, is actually efficient. With most people riding the same style bike, a dominant speed takes over, and trying to exceed it means you are constantly trying to find a place on the bike path to pass, zipping away only to run up to the next group cruising along. When there are enough bikes about to actually constitute “traffic”, suddenly, other factors apply. Like the impatient commuter making 20 lane changes in stop and go traffic only to find himself back behind that same truck, sometimes the fastest speed is the one that moves you smoothly and evenly with those around you.

In Los Angeles, you become so accustomed to viewing the riding environment as a threatening wilderness, full of threats to be avoided…challenges to conquer. Beyond the efficiency of moving through space as part of a steady, non-turbulent flow, what does it mean to the other parts of our routine to move in concert with those around us rather than trying to grab the most (speed or whatever else) the situation seems to allow?

That new bike (blog) smell

Hello. Long planned, but repeatedly delayed, this blog has begun. I’ll be using it to write about a variety of topics from a number of viewpoints. But a recurring theme will be bicycles, and I couldn’t think of a better way to begin than with a new bike.

HKSNew to me anyway. Few purchases are as fun as the new bike; learning the ride characteristics, figuring out the quirks…realizing what needs some work. Here is an HKS city bike. Made in Germany, sturdy, simple, and unglamorous. It will be my main means of transport while I am on an extended visit in Berlin.

It can’t rightly be called a classic. It has early Shimano Positron shifting (the first wide spread indexed shifting system) which probably dates it to around 1980. But it has all the design goals that really define what cycling in a city like Berlin is all about. The upright riding position that emphasizes comfort and visibility, simple gearing to handle moderate terrain at a reasonable speed, fenders and chain guard to make it a bike that is ridden in all weather wearing regular clothes, generator light and rack so it is transport for any time of day for most simple trips. And finally just a bit of flair. I love the just slightly rakish half chain guard.

This is the bike as “tool”. It is not ridden for its own sake, it serves as a means towards other ends. The bike as an integral part of one’s daily life rather than as a distinct activity. In many ways, that is the most obvious quality of bicycles in Berlin. While in America the bike is almost exclusively a hobby, sport, or lifestyle, here it is mainly a utilitarian object, simple effective transportation.

I hope to explore many of the issues behind and effects of this simple distinction. I’m pretty confident my new ride will help me explore the city as well. Now I just need to get my 20+ year-old drum brake to stop squealing.