Fridge on a bike trailer

Bike Trailers vs. longtail bikes

Christiania cargo bike
Christiania cargo bike

There are many alternatives to haul cargo on bikes – a fact that was demonstrated daily on the streets of Copenhagen during the year we lived there.  By far the most popular were Christiania bikes, which were used to haul various daily goods including kids and girlfriends.  There were also quite a few bikes with extended front ends, which look a bit awkward but have the advantage of keeping your cargo in view.

With such a variety of hauling solutions, the one cargo bike I never saw in Denmark is the one I’ve focused on in this blog: the longtail bike.  One might wonder why I haven’t broadened my scope a little.

The main reason is my readership.  Although my blog is read in many countries, roughly 80% of my readers are in the United States and Canada.  Since I’m most familiar with the transportation landscape in North America, I can offer suggestions and opinions that are appropriate here.  My experiences in Denmark strengthen my conviction that transportation must be tailored to local circumstances.

There are three things that make a Christiania bike a better choice for Denmark than the U.S.: flat geography, advanced biking infrastructure, and higher expectations or education about bikes in general.

As I’ve often said, flat terrain is a huge advantage for Danish bikers.  The Christiania bike is heavy and not very aerodynamic.  I rode one once and it required some effort to push it through a stiff Danish headwind.  I’m not sure I could pedal one up a Seattle hill, even without a load.

The bike infrastructure in Copenhagen enables a diverse ecosystem of bikes.  For example, many bike lanes in Copenhagen are wide enough for one Christiania bike to pass another without impinging on car lanes.  Contrast that with my own city, where some bike lanes aren’t wide enough to accommodate a single Christiania-sized bike.

Finally, these kinds of bikes are viable because Danes use their bikes differently than Americans do.  They tend to ride relatively short distances at a relaxed pace.  They are accustomed to seeing all kinds of citizens on bikes, including many senior citizens who are more comfortable on a tricycle than walking.  Bikes of many shapes and sizes are optimized for diverse needs.  Here’s a video that illustrates what I mean. Check out the guy carrying 4 kids, a kid’s bike, and a whole bunch of other stuff on his bike:

Bike trailers

Bike trailers represent another cargo hauling strategy that I rarely saw in Denmark.  I’m guessing that’s because the added length, the extra wheels, and the location of the cargo farther behind you make a trailer difficult to maneuver in cozy urban settings.  But I’ve been getting occasional emails from readers wondering about towing a trailer with an electric bike, so perhaps it is time to tackle the subject.

Before I start, I should say that I have never used a trailer, and I’m in the precarious position of expressing opinions that aren’t based on actual experience.  I’m hoping that my trailer-towing readers (I know there are some of you out there!) will let me know if I say anything stupid.

From a price standpoint, a trailer-based cargo bike has some advantages.  If you already own a bike, you can buy a nice trailer for about $500.  If you were to add an electric motor and lithium-manganese battery for less than $1000, your outlay would be at least $800 less than the least expensive electric longtail bike I’ve described in previous blog posts.  So how do they compare on features?

The trailer gets points for flexibility.  When you’re not carrying cargo, you can enjoy a nice electric bike that’s a little more nimble than a longtail.  It will fit on the rack of a suitably-equipped bus – not something most longtails can do.

Fridge on a bike trailer
Fridge on a bike trailer

The trailer can also carry heavier or awkward loads due to its longer cargo deck and lower center of gravity.  For example, here’s a story of a guy moving a refrigerator using a bike trailer.  That’s not going to happen on a longtail!

However, if you’re thinking of using your cargo bike for more common daily chores (carrying kids and/or groceries, for example), a trailer will be overkill.  It’s not going to be as easy to pack or to ride.

Everything I’ve said so far might be obvious, so the real question is how the electric motor is going to perform with a bike trailer.  Since it’s going to provide a significant boost to your leg power, the motor will

  • Decrease your effort
  • Increase your speed
  • Increase the amount of weight you can haul
  • Increase the slope of hills you can climb

The last 3 items on that list arouse some safety concerns.  Since the wheels of the bike trailer don’t have brakes, the momentum of your cargo will add stress to your bike’s brakes without adding weight to your wheels.  This increases the chance of skidding.  As I discovered here, a skidding front wheel radically diminishes steering control.  That would be a bad situation on a normal bike, but the bike trailer adds another complication.  Unless you’re stopping in a perfectly straight line, the trailer will impart a sideways force to your bike during hard braking.  I’ve seen enough jack-knifed trucks to be sure I don’t want to see a jack-knifed cargo bike.

What does this have to do with the electric motor?  Nothing, except that the extra power and speed provided by the motor will complicate emergency stops.  A hard stop at 25 m.p.h. is qualitatively different from the same stop at 15 m.p.h.  If my experience is any guide, it’s hard to resist the temptation to open up the throttle when there are no obstacles in sight.  Unfortunately, it’s the obstacles you don’t see that lead to emergency braking situations.

My gut feeling (again without practical experience) is that bike trailers excel at transporting big loads at moderate speeds over relatively flat terrain.  An electric motor would be helpful to get the load moving without shifting through all your gears.  Your safety sense must be your guide in determining how fast you allow that motor to propel you.

I have one other concern.  There’s a reason you don’t see a trailer hitch mounted on a Toyota Prius: the car’s drivetrain isn’t designed for it.  Likewise, most bike motors weren’t designed to tow heavy trailers.  Even if they work for awhile, the extra wear and tear may not be covered by the manufacturer’s warranty.  Anyway, it’s something you might investigate before pursuing this course.

If you use a bike trailer, and especially if you’re using a motor, I’d love to hear about your experiences.