A design opportunity is emerging for a long-distance electric vehicle that weighs more than a bicycle but less than a motorcycle. Ebike hobbyists are leading the way.
Last September I made a 240-mile journey by electric bike from Ithaca NY to New York City and back. The trip was not that remarkable in itself. No records were broken; there were no physical or mental challenges that needed to be overcome. In fact, that was the point of the journey: to show that a long-distance journey by electric bike could be easy and enjoyable. Part 1 of this series compared long-distance bike and car travel in general. Part 2 described the trip itself in detail. This Part 3 describes the modified touring bike I used to make the trip. What’s surprising about my bike is not how technologically advanced it is, rather the opposite. My bike is an electrified steel frame Nishiki Cresta touring bike from 1982 with a BMC rear geared hub motor.
Long Distance Ebike Design Criteria
What would the ideal long-distance electric bike look like? First of all let’s define our terms. By long-distance I mean able to travel 100 to 200 mile a day. By electric bike I mean a bike not much heavier or faster than a (heavily loaded) muscle-powered touring bike, say weighing up to 150 pounds and capable of 100 miles at an average speed of 20mph. There are no commercially available electric bikes that meet these specs; happily, anyone moderately handy can make such a bike using off-the-shelf ebike components.
There are two design routes to achieve these specs. One route is based on raw power. The idea is to load up a longtail cargo bike with lots of batteries (say 40 or 50 pounds of batteries for a total of 2,500 watt hours) and a large powerful direct drive hub motor. Because everything is so heavy you will need a cargo bike with large tires and front suspension. Total weight (without rider, but with batteries and motor) is around 120 pounds. Efficiency is around 25 watt hours per mile. This is the kind of bike I’ve used on previous trips and this was the kind of bike recently ridden by Troy Rank on his epic 4,400 mile journey. And this is the sort of bike you’d need if you are biking in wilderness areas on dirt roads and carrying full camping gear and food.
The Lightness and Efficiency Route
For my trip to NYC I decided to follow a different design route based on lightness and efficiency. First I assumed I would be riding on paved roads in civilized areas. I deciding not to bring full camping gear and food, but to stay at hotels and eat at restaurants. I began with a lightweight but strong touring bike with narrow tires. To this I added an efficient medium-power geared hub motor and 32 pounds of batteries, for a total of 2,000 watt hours of energy. Total weight of bike, motor, and batteries was about 85 pounds. Efficiency was about 18 watt hours per mile.
There were a couple of cool side effects having a small touring bike rather than a large cargo bike. One is that I could lift the bike. A couple of times it was necessary to lift the bike up flights of stairs, and at one hotel I even took it into an elevator and up to my room! I was also thankful one time when I ran out of battery energy. I had no difficulty pedaling the last few miles to a hotel.
A traditional touring bike has another benefit over a longtail cargo bike: its drop handlebars can lower wind resistance. At 22mph, riding in a crouched position can reduce the power needed by almost half. Currently no commercially available electric bikes have drop handlebars. Perhaps this is because people who ride fast enough to require drop bars do so for exercise, not for utility, so they don’t want an electric motor. I predict more ebikes will have drop bars as more people use ebikes for long distance travel.
I didn’t do much to lower my wind resistance other than use drop handlebars. However, wind resistance is a critical design issue to resolve for long-distance ebikes. If Ebikes are going to be able to travel at 25mph or more, the wind resistance issue needs to be solved. Would fairings be worthwhile? This study showed that fairings actually increasd wind resistance in most positions. Lowering wind resistance can be counter-intuitive. This study also showed, for example, that front panniers lowered wind resistance significantly but “aero” wheels did not. Would the lower frontal area of a recumbent be worthwhile? How about a bike that can convert from an upright bike for around town to a recumbent for long straight trips? I found that to some extent, drop bars provide just this sort of city to country bike conversion: when in town I rode at lower speeds with my hands on top of the bars; on long straight country roads, and especially fast downhills, I rode in the crouched position. It would be hard to come up with a new technology that could beat the simplicity and effectiveness of drop bars.
Handling & Suspension
When I first got my 1982 Nishiki Cresta touring bike a couple of years ago, I was disappointed with its handling. As I rode it around town it just didn’t feel responsive. It was not fun to ride. However, when I finally set it up fully loaded with 50 pounds of stuff, it showed its true purpose. I found I could barrel down the hills of Pennsylvania at 40mph, hit a bump, and not waver a bit. Its handling was rock solid, but only when loaded. A long-distance ebike needs a frame geometry that provides this kind of stable handling going fast and loaded, which may necessarily be at the expense of responsiveness.
I did however miss the front suspension of my Xtracycle mountain ebike. Those bumps may not have thrown me, but they were very jarring. I think the ultimate long distance ebike would have small front shocks, such as those on adventure hybrid bikes.
Ebike throttles only fit straight handlebars, so I had to improvise a solution for my bike’s drop bars. I placed two throttles on the inside of the brake levers so that the throttles are accessible by my thumbs from both the crouched position and while riding with hands on top of the handlebars. I put throttles on both sides of my handlebars so that I could continue holding down a throttle while I shifted gears with my other hand. Future long distance ebike designers may find a more elegant solution.
Battery Mounts and Connectors
Grin Technology makes a great battery mounting plate that’s designed to work on most racks in many positions. I set up two eZee 48v10ah batteries on the sides of my front rack, and I strapped two AllCell 48v13ah batteries within my rear panniers. There is a great opportunity here for someone to develop panniers designed specifically to hold ebike batteries!
I made a wiring harness with especially thick 10 gauge wires so that it could handle lots of current. I connected each matching set up batteries in parallel so that I had in effect one 48v20ah battery in the front and one 48v26ah battery in the rear; I used one set in the morning and the other in the afternoon. One reason I connected the batteries in parallel is to decrease the load on any one battery. I’ve had single batteries become overloaded and cut out on long hills on a fully loaded bike.
My dashboard consisted of a Grin Tech Cycle Analyst to monitor my batteries and an iPhone to run navigation software. I recognized that my iPhone would be a critical safety device, so I spent the money to get an expensive waterproof iPhone cover. I also set up a Grin Tech USB voltage converter so that I could recharge my phone directly on my handlebars from my ebike batteries. One can imagine this whole dashboard menagerie merging into one device on long distance ebikes of the future.
One major drawback to my long distance ebike is the cost of batteries. My bike, motor and electronics (without batteries) cost about $1,300, which is about the same price as a high-end new touring bike (such as the Surly Long Haul Trucker). But the four batteries cost about $3,600. This is way more than most people could pay. Even I was only able to travel with this many batteries because I own an ebike rental business, and I was able to borrow a few of my company’s batteries. This cost will probably halve in the next few years as battery technology, driven by the automotive industry, continues to advance. We can also expect equivalent batteries to drop a few pounds in weight. But ideally the solution will be infrastructure. As I mentioned in my previous post, some ebike tours in Europe use a battery exchange program so that bikers can swap used batteries for fresh ones along their journey. Another development is high-speed chargers coming on the market that enable ebikers to charge up in half the time as current chargers–see for example Grin Tech’s new Cycle Satiator. These new chargers would make it possible for long distance travelers to carry fewer batteries because they could charge up during short breaks.
Our planet desperately needs alternatives to the automobile. Ebikes have proven their ability to replace cars for personal urban transportation, and even many delivery applications. But the use of ebikes for practical long distance travel remains woefully unexplored. The highway is lonely for long distance ebikers. So I encourage you, my readers, to take up the challenge. Make long distance ebike trips. Find out what works. I look forward to seeing what innovations you come up with.