Thursday, September 12, 2013

Bikes Aren't Cars - and it's a good thing

The title of this post probably rises to the highest peak of “Duh” mountain – glaringly obvious to anyone with half a brain. But as obvious as it seems, all kinds of people – cyclists and non-cyclists alike – continually seem to forget that point in a wide array of bike-related arguments.

Here’s an argument I hear when cyclists talk about the direction that bicycle design is heading. It goes something like this: Cars and even motorcycles now have computer controlled engines, anti-lock disc brakes, power steering, “fly by wire controls” and all kinds of technological advancements, and they’re better for it. Why shouldn’t bikes be the same? Why do luddites and “retrogrouches” keep insisting that bikes stay stuck in the past?

Back to the obvious. Bikes aren’t cars – or motorcycles, either. Comparing them misses the point of what makes bicycles great; turning the bicycle’s virtues into vices. Bicycles, by their very nature, are simple machines. Cars, and even motorcycles, are inherently far more complicated to begin with than bicycles, and they need to be. Much larger, much heavier. Consisting of many more systems, made up of many more individual component parts. They need far more energy to move and stop. They are capable of much higher speed, and likewise capable of much more chaos and carnage should those components or systems fail to work properly.
Modern tech helps cars -- and they need it.
image from

Consider brakes. For decades, most cars, trucks, and motorcycles used drum brakes. For a long time, these brakes were mostly cable-operated, then hydraulic. The change to hydraulics was significant when one considers the effort needed to stop a 4000 lb. car. But being more difficult to cool, drum brakes could be prone to overheating and thereby were more prone to “fade” – loss of braking power under hard use, so better cars started using disc brakes – first on the front (with drums on the rear) and then both front and rear (some less expensive cars and trucks today still use the front disc/rear drum setup). Disc brakes could be cooled better and gave improved stopping power without as much “fade.” In more recent decades, anti-lock brakes, which require delicate sensors and some pretty serious micro processing power, made it safer to stop in slippery conditions. The braking systems have become much more complicated – yet the improvements have made cars much safer and easier to control.
Modern tech makes motorcycles faster, more efficient
and maybe a little safer
image from

Now the push is to add disc and hydraulic braking to bikes. But people tend to ignore the fact that braking on bicycles is already hard to improve beyond small gains. The power needed to stop a bicycle and rider is a tiny fraction of that needed for car. With most cable-operated rim brakes today, modulation is predictable, fade is minimal, lever effort is light, and braking power is strong enough to lock up the wheel if desired. All hard to improve upon. In all but the most extreme conditions, controlled safe stopping is easy. In situations where disc brakes and hydraulics are supposed to offer better performance, the actual difference is still very small, and not without trade-offs (more on that in a future post).

Consider suspension. Cars and trucks have had some form of suspension almost from the beginning. Apart from a few holdouts (Harley “hardtails,” for instance, which continued to be produced up to 1957) most motorcycles have used full suspension at least since WWII. Imagine driving a 3–4,000 lb. car, 5–6,000 lb. truck, or even a 600 lb. motorcycle without suspension. Imagine that kind of weight slamming rigidly into a pothole, a speed bump, or some uneven railroad tracks. The mass and the speed would combine to make the force unbearable. It’s basic physics. And now, fully independent, computer-controlled suspension can adjust for uneven pavement, different surfaces, and correct for things like oversteer or understeer, making cars much safer to handle.

Is this really necessary? On a Huffy?
image from
Since the late 1980s, engineers and designers in the bicycle industry (apparently coming from motorsports backgrounds) have insisted on bringing bicycles into the “modern age” by adding suspension both front and rear. But bicycles have a small fraction of the mass of even the lightest motorcycles, to speak nothing of cars and trucks. The force of hitting a bump is considerably less. The speed is much slower, and the bicycle is more maneuverable, so it’s much easier to avoid the bumps in the first place. And good riding technique allows us to safely soak up most bumps without mechanical suspension. For downhill mountain bike racing, that suspension can be a real benefit – but think of all the people out there riding full-suspension bikes (which they've been convinced into thinking they need) on pavement, on bike paths, and on groomed trails – bobbing along on springs, dampeners, and elastomers, held together with increasingly complicated linkages. What benefit do they really get, and is it worth the added cost and complexity?

Cars and motorcycles have switched from mostly mechanical engine systems and controls to microprocessors. Mechanical carburetors have been replaced by computer-controlled fuel injectors. Mechanical point ignition systems have been replaced by computer-controlled electronics. All these changes have led to better gas mileage, cleaner emissions, and engines that are more reliable. All good things. On the other hand, while they are less likely to break down, when they DO break down, it is unlikely that anybody but a highly trained mechanic will be able to do anything about it. When it happens, our only choice is to stand at the side of the road and wait for the tow truck.

Today, bicycles are moving towards electronic shifting systems. Their tiny computer brains are able shift quickly and reliably, even under hard riding conditions. I have no doubt that they work really well – the R&D guys at Shimano have tested their Di2 thoroughly to make sure it’s completely dummy-proof. And, like all the new technologies that start at the top price range, these systems will filter (are filtering) down to even the entry-level price points (today Ultegra, soon 105, etc.).  I’d be willing to predict that the next step in electronic shifting will be to incorporate cadence and wheel speed sensors to allow the computer to shift gears automatically. When the stuff works, it works well – but when something goes wrong, fixing it on a ride will be unlikely. Wait by the side of the road or the trail and wait to be picked up by a patient spouse or a good friend with a car and some time to kill.

Cars and motorcycles are complex to begin with -- by their very nature. The added complexity of modern technology helps to keep their systems working properly, improves their efficiency, helps compensate for poor driving skills, and even helps make them safer. Bicycles are (and should be) simple and highly efficient machines. Adding technology and complexity does not make them more efficient, and it doesn't necessarily make them safer. Small gains in performance are often offset by other drawbacks. And the added cost only hurts accessibility and adds to the perception that bicycles are just fancy toys for rich people.

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