This is a continuation from @[email protected] 's comment about the Cyberdrop ebike trailer, on the practicalities of bigger or heavier ebike configurations. But I’m open to discussion on the same challenges presented to e-scooters, e-longboards, or anything else under the micromobility banner, as size and weight eventually implicate practicality for all modes.

Ebikes have enabled some very creative builds, with an ever-broadening variety to meet diverse rider needs. Borrowing from the familiarity of acoustic bicycles, most of these ebikes can be accommodated in the same facilities, so not as much thought was previously needed about ebike compatibility with its surroundings. But with some of these larger, heavier, more powerful machines, this is going to quickly become a problem; we’ve already seen conflicts with other two-wheeled users and pedestrians. This strife costs goodwill with the public at large, and may invite onerous governmental regulations.

In my mind, the approach to analyzing this is to identify which ebike parameters result in reduced real-world practicality under certain scenarios. The idea here is that all parameters must come with some tradeoffs, and sometimes those become really apparent under certain circumstances. I posit this cursory list of parameters, as a starting point:

• length
• width
• weight
• height
• cargo capacity (volume)
• power
• speed
• minimum turning radii
• parking
• number of wheels
• number of riders

As for scenarios, here are a few:

• (A) Commuting into/through downtown on 2 or 4-lane roads with paved, 2-3 ft bike lanes, possibly with a curb-separated, two-way bike path adjacent to the road, 6 ft wide in total
• (B) Leisure stroll on a suburban, winding 10 ft multi-use path paralleling a creek, with 8 ft of paved surface width and 2 ft for dirt running track, adjacent to sensitive wetlands separated by rope fencing
• © Intercity jaunt orbiting around a metro area, from one suburb to another through rural/agricultural areas, via speedy, straight 2-lane country roads with intermittent 2-5 ft paved shoulders, full of tar snakes.
• (D) Adventure run up and down a hilly Forest Service road, with alternating between rough gravel pavement and dirt, searching for a camp site overlooking the valley/lake/metro. No other traffic, homes, or people for many kilometers.

With all that said, I think the single most-impactful parameter of an ebike that reduces practicality the most is length. My reasoning is that length reduces an ebike’s ability to navigate horizontal curves, and vertical curves (aka hills). In the scenarios above, something that is over 3 meters (10 ft) long would be outrageous in the city, scorned in the suburbs, unmanoeuverable on county roads, and would bottom-out in the sticks.

In scenarios C and D, it’s possible to be long and narrow, or long and tall (for ground clearance), but taxing my imagination, I can only think of two very-specific applications that would meet this: a canoe hauler, and a “glass truck” ebike to move building material vertically.

It gets worse when length is paired with some of the other parameters, like length and width (see Cyberdrop earlier) or length and height (ebike billboard?) or length and riders (rigid ebike bus?). Don’t get me wrong, these are interesting ideas, and I’d pay good money to see a length-and-weight ebike troika hauling the Space Shuttle Endeavor, but there would be too many compromises for regular use.

Moving to the next item, width is another critical parameter, because of all the width restrictions that presently exist. Older cities here in California with on-street bike lanes are lucky to have 3 ft, often narrowing to 2 ft at intersections, if they even continue through the intersection at all. The Vehicle Code here removes the requirement for cyclists to keep rightward if road conditions change, but since the width of a bicycle or ebike is not defined in law, there’s some ambiguity as to how an overly-wide ebike would navigate on-street. The situation is worse on off-street paths, where wide ebikes would essentially become rolling roadblocks, especially at curves or in narrow passages like underpasses.

As for weight, it’s not too impactful on its own but combined with speed or width, such an ebike could become a hazard to other road users or to the rider very quickly. A UPS cargo ebike operating up to 25 kph (15 mph) in scenario A is reasonable enough, but hauling a sofa in Scenario B would raise a few eyebrows and cause parents to hold their children in a place where they should feel safe from being run down.

As a closing thought before this gets too long, it’s notable that automobiles have the same set of challenges, as exemplified at the largest and heaviest of commonplace automotive endeavors: RVs. RV trailers are at the very edge of what can be operated with a normal Class C driving license in California. 10,000 lbs GVWR trailer behind a minimum 4,000 lbs GVWR tow vehicle, often attached with fifth-wheel coupler, yielding overall lengths up to 40 ft. These behemoths simply cannot be stored or driven in the city, and even in many sprawling suburbs, still look deeply out of place when parked curb-side, often brushing up against branches due to their height or width.

If ebikes or e-trailers reach a relatively-similar state of big-ness as RVs, then we’ll know we have erred. Let me know what y’all think about this topic.