How Fast is Too Fast For an Electric Bike?


The line between motorcycles and e-bikes is becoming blurrier as time goes on. E-bike motors are getting smaller, batteries are getting more powerful, and manufacturers are learning how to put together cheap, effective e-bikes that can zoom around at high speeds. But where is the limit? 

Many e-bikes can reach even speeds faster than 28 MPH, however, without proper gear and riding conditions, even 15 MPH can be too fast. E-bikes are allowed to go 20 MPH with a throttle, although the limit can be 28 MPH, depending on the local regulations and whether the e-bike has pedelec mode. 

How fast is too fast? Let’s talk about speed limits, bike maintenance, and what factors might affect how and when you push your e-bike to its limits.

Speed Limits and Regulation

Unfortunately, there’s no one-size-fits-all law that governs how fast you can go on an e-bike in the United States. Instead, different states (and some cities) have their own regulations that dictate how fast your bike can go and how powerful it can be. 

That said, many states have similar laws. The most common speed limits are 20 MPH for e-bikes with a throttle, 28 MPH for e-bikes in pedal assist mode, and a maximum motor output of 750 watts.

You should not take these laws as gospel. Enough cities and states have regulations that depart from the norm that it’s worth taking the time to double-check things for your specific region. 

New York City, for example, does not allow e-bikes that go over 20 MPH in any capacity, meaning that NYC residents will need to adjust their bikes to ensure regulatory compliance.

Running afoul of the law while on a bicycle might seem unlikely, but it’s definitely a headache that you’ll want to avoid if you can. 

Cops can and will pull over bicyclists that violate traffic laws. Doing a little bit of research and possibly reprogramming your controller is a small price to pay to avoid hundreds of dollars in fines or an impounded bike.

Safety Issues and Physics

The faster you go on your bike, the more likely you are to injure yourself or someone else in the event of an accident. This might sound obvious, but don’t ride your bike faster than you can safely control it. If you feel uncomfortable or like you cannot make the bike do what you want, slow down until you feel like you’re in control.

As far as crashes are concerned, force corresponds with the square of velocity. This means that crashes get exponentially more dangerous as your speed goes up. In this respect, going 20 miles an hour is four times as dangerous as going 10 miles an hour. 

Your ability to react to obstacles also diminishes as your speed increases, while your braking distance increases at the same time.

This isn’t to say that you can’t go fast on a bike. Doing 20, 30, or 40 MPH on a bike can be very safe – under the right conditions. 

If you’re wearing a helmet, riding on well-maintained roads with good bike paths, and you’ve got plenty of visibility to see oncoming hazards, it’ll be fairly safe to ride at high speeds. When you start removing these factors, however, you’ll want to reduce your top speed to ensure that you don’t wind up injuring yourself or someone else.

Maintenance and Performance Issues

Controller Issues (What do I do if my bike goes too fast to pedal? How do I fix my bike’s super fast launch speed?)

Most modern e-bikes have programmable controllers. This doesn’t mean that you have to type advanced computer code into your bike’s display panel. Instead, it means that you can access a hidden menu that will allow you to tweak various motor parameters. 

If your bike is putting out too much power in some circumstances, you can usually find an appropriate tweak somewhere in this menu. 

Try to turn down the power on lower pedal assist modes to keep the pedals from turning too fast or prevent the bike from taking off like a rocket when you start to pedal.

Battery Issues (How does riding fast affect my bike’s battery?)

E-bike motors are happiest when you’re going fast. This means that you can pretty much go as fast as you want without having any detrimental effects on your hardware. Going slowly up a hill, however, is actually quite taxing on your motor. 

This doesn’t mean you should avoid climbing hills, but rather that you may want to consider helping your bike out with a bit of human power to avoid putting unnecessary strain on your motor and battery.

On the flip side, your battery has a big role in determining the exact top speed of your bike. A fully-charged battery at the right temperature will give you a few miles an hour of additional top speed. 

If you’re having problems getting to 28 miles an hour, try charging your battery to full immediately before your ride.

Drivetrain and Wheel Issues

E-bike motors put out a lot of power. When you combine the power output of a motor with the output of your legs, you quickly reach a level of force that regular bike parts aren’t designed for. 

This means that every part of your drivetrain will wear out more quickly. Expect to replace more chains, derailleurs, and cassettes on your e-bike.

This isn’t necessarily a function of top speed. Instead, it’s a function of how often you use how much pedal assist. Your drivetrain doesn’t really care if you’re going up a hill slowly or sprinting along on flat ground. 

Any time you’re putting out hundreds of watts of power you’ll wear out your components faster than an unassisted cyclist.

Another big thing to look at is your rear wheel. The torque of your motor can loosen your spokes fairly quickly, especially if you’ve got a heavier bike. Again, this has less to do with your top speed and more to do with your use of the motor. Be sure to check your spoke tension occasionally and tighten up your wheels as needed.

Bike Commuter Hero

When it comes to Cycling to Work, SAM IS THE MAN because he doesn't just talk the talk, but he also walks the walk - or rides the ride, to be more precise... Come, pedal with me and be a HERO!

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