Updated 2025
First, I’ll say I think that e-bikes have a place, and open up “biking” (e-motor biking) for a number of people that could not do it or enjoy it as much (or at all) on an bicycle or non-motorized adaptive bike. And of course to some their ebike is more fun than their analog rig in some or all instances. To say one IS better is a futile exercise imo. It’s not quite like saying punk is better than jazz, but “better” isn’t the way to approach this subject, and agreeing to disagree might make more sense, if the parties have sense enough to realize the subjective possibilities.
I’m not going into the positive space here, just some things that could be construed as negative by some, and should be considered when planning trails, thinking about safety, and protecting resources.
Law 2
It takes more distance to decelerate to a stop as mass increases…mv^2/2ma (law 2 f=ma), BUT more mass creates more friction on the ground, so in general light and heavy bikes will stop at the same time, the distance is independent of mass (sort of, or it is ignored anyway): d=v^2/2g(f+G) where f is the friction coefficient and G is the trail grade. Masses cancel, but still, the heavier bike will have to use more force on a trail to stop in the same distance, and will have more momentum.
Without measuring braking soil displacement on the ground, I can’t say if it’s greater with motor bikes than bicycles, but at this time I can’t see it being more for heavier bikes, but maybe I am mistaken. If there is a difference is it an “insignificant” difference? If stopping via sliding or skidding, I could certainly see e-bikes plowing more earth due to the extra mass.
Collisions
While masses might cancel with braking times, mass is everything with collisions. In 2024 e-bikes often weigh 30-50 pounds more than analog bikes. More mass means more inertia, so collisions with people or other objects are going to be more violent. An ebike has more momentum by virtue of it’s mass and will transfer more momentum to the other object (and win). E-bike to bicycle, and e-bike to pedestrian collisions will be more hurtful by virtue of mass, as well as speeds, which on average are faster on e-motor bikes. I had my bike land on me more than once, I’m not looking forward to potentially twice the mass in that scenario. Perhaps one-way trails are something to consider for e-bikes. I look forward to seeing data on e-bike injuries in the coming years.
Ruts
Another issue with e bikes is the psi on the ground, they will sink and displace more soil than lighter bicycles. There are more pounds over nearly the same contact patch. E-bikes “might” cause deeper ruts and create brake bumps faster or in places analog bikes would not. [How do we stop brake bumps to begin with? I won’t elaborate in depth here except to say slow people down before the brake bump area, and think about what goes on after or at the area in question. What’s causing the slowdown there, should we slow people down beforehand or help them get through without hard braking by addressing the trail ahead of the bumps so they flow through smoothly?]
Displacement Torque
E-bikes have more potential to cause erosion via displacement because riders essentially have nonhuman, i.e. motorized, leg power, transferring more torque, or rotational force, to the ground patch, thereby displacing more soil. In theory anyway. Is torque the elephant in the room on the e-bike displacement question? I haven’t seen studies yet, and there is a lot to unpack here. Regardless, expect increasing erosive damage as grades increase with motorized legs.
Will we have to adjust 2-way trails or climbing trail design specifically for the local soil and expected torques? Motor control systems that regulate torque vary in quality, and I assume displacement damage, but I haven’t seen any data yet. Can a possible argument against ebikes on two-way trails be pulled from the numbers here? How many analog bike climbs does one e-bike bike climb equal? We know all too well what a motorcycle can do blasting up a steep hill, an e-bike is similarly a motor bike, but I don’t expect the same damage compared to a pedal assist e-moto. How much more than a bicycle? Can acceleration and hill climbing be managed to limit tread damage via the motor controller? How much easier or likely is a e-motor bike to slip and displace soil?
Fire
Lithium batteries can, and have caught on fire, usually charging, but not exclusively. Is it a question of when, not if, an e-bike will set a treasured forest or forest and houses ablaze, especially as the numbers go up. How many dice rolls, is it Russian Roulette?
Carry a small fire blanket? A class B fire extinguisher? Lithium fires are essentially liquid fires like gasoline, don’t use water, it will spread the fire. Use foam, powder, carbon dioxide, or dirt to limit oxygen.
Use and Abuse
Trails need a break too? Will e-bikes mean an overall increase in the number of people on trails? And will people do more miles, possibly laps, on the same segments? How many more wheel passes will e-bikes bring to a resource? I don’t know that we should “cap” the numbers of passers by, but this is nonetheless an important resource consideration. Trails can be “loved to death,” especially in inclement weather…too wet or too dry amplifies the erosion of trails. Faster bikes kick up or displace more soil, especially when very dry, trail sediment blows away in the wind. Heavier bikes sink in soft soils, trails ride away spoonful/s at a time on tires, frames, clothing, and shoes (ebikes typically have more surface area and could carry a few more spoons of dirt away). I won’t get into trail closures here, but…ideal conditions that limit erosion are far and few between in some locations, regardless, the apparent differences between e-motor bikes and bicycles in resource use, wear, and damage seem significant on the surface.
Road Kill
OK, call it Trail Kill. Bikes do kill critters, they run them over. Granted it is rare, anecdotally at any rate, but how could increased speeds and/or use dynamics change this outcome?
Unexpected Sights
It will take some time for people to get familiar with high speed uphill travel…”do my eyes deceive me, are they approaching that fast?” A few encounters and I assume most people will internalize e-bikes speeds as a new norm. Sight lines might need to be extended beyond what we anticipate as adequate. In some locations or trail segments this might not be practical. Choke points, rock gardens and other means could work, but could also change the character of the segment/s in question.
Land Managers Are Kings
I don’t like idea of royalty, nor top-down arrangements and hierarchies in general. Nevertheless, call it an “appeal to authority” if you want, at the end of the day users and user groups can go back and forth as much as they like about the justifications for or against e-bikes on trails, but ultimately whether they have a place or not is not their decision. The land manager or agency in question are the Rulers. If I was the land manger in a potentially fire prone area or responsible during a Red Flag Warning spell, I would sleep better knowing that every other rider wasn’t carrying a potential blow torch and an extra 40 pounds of potential harm with them.