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How Fast Is Too Fast for an E-bike?

by DYU cycle 03 Jul 2024

With a boost from an electric motor, they can reach higher speeds than traditional pedal bikes. This increased speed offers exciting new possibilities but also raises important questions about safety and legality.

In this blog post, we'll tackle the key question: How fast is too fast for an e-bike? We'll cover UK speed regulations, factors affecting e-bike speeds, safety considerations, and how to balance speed with battery range - so you can enjoy the advantages of e-biking responsibly.

Electric bicycles are becoming more popular in cities

UK Speed Limits and Regulations for E-bikes

In the UK, there are legally defined limits on e-bike speeds and motor power outputs. These are outlined in the Government's Electrically Assisted Pedal Cycle (EAPC) regulations:

  • Maximum power output of 250 watts
  • Maximum assisted speed of 5 mph(25 km/h)

If an e-bike exceeds these limits, it may be classified as a motorcycle, moped, or motor vehicle. This would then require vehicle tax, registration, and insurance - plus the rider needing a driving license.

Riding an e-bike that goes over the 15.5 mph assisted speed limit could result in fines or legal penalties. Police have the power to issue Fixed Penalty Notices for such offenses. The fine is currently £100, so it's crucial riders comply.

What Affects an E-bike's Actual Speed?

While those are the legal maximums, several factors influence the real-world top speed an e-bike can reach:

  • Motor Power- More powerful motors (up to 250W) enable higher speeds before the assistance cuts out at 15.5 mph.
  • Battery Capacity- Larger batteries can maintain higher speeds for longer by supplying more power to the motor.
  • Rider Weight- Heavier riders require more power from the motor to maintain the same speeds.
  • Terrain- E-bikes go faster on flat/downhill sections compared to inclines where the motor has to work harder.
  • Pedalling Input- On pedal-assist e-bikes, the rider's own pedalling contributes to the overall speed achieved.

An e-bike's top speed depends on the combination of motor power, battery capability, and rider input. But the motor system must legally cut out assisted power at 15.5 mph.

Throttle vs Pedal-Assist - Bikes with a throttle can reach the 15.5 mph cut-off without pedalling. Pedal-assist models require rider input to hit that speed.

So, while factors like motor size and battery influence maximum performance, all legally compliant e-bikes in the UK have an assisted speed limit of 15.5 mph enforced by the motor cut-off.

Safety Risks and Precautions at Higher E-bike Speeds

Even at the legal 15.5 mph assisted limit, e-bikes can reach higher speeds than many cyclists are used to. This increased velocity raises some important safety concerns:

  • Reaction Time- At higher speeds, you'll cover more ground during the time it takes to spot a hazard and begin reacting to it. For example, at 15 mph you travel around 22 feet every second.
  • Braking Distances - E-bikes require longer stopping distances than regular bikes, especially when riding faster. Brake components also wear faster at higher speeds.
  • Stability and Control- The faster you go, the more difficult it becomes to maintain control, navigate tight turns, and quickly change direction if needed. Excess speed reduces stability.
  • Visibility for Others - Pedestrians and drivers are less likely to see you approaching at higher speeds until you're very close. This increases accident risks.

To mitigate these risks, there are some key safety practices for higher-speed e-biking:

  • Wear Protective Gear - A properly fitted cycling helmet is an absolute must. Gloves, knee/elbow pads, and bright clothing also help prevent injuries.
  • Be Defensive- Ride assertively but defensively. Constantly scan ahead for potential hazards and obstructions that may require evasive maneuvering.
  • Use Front/Rear Lights- Having your lights on makes you more visible to others, even during daytime rides.
  • Control Your Speed- Use your e-bike's power delivery moderately, don't max it out everywhere. Adjust speeds for conditions and terrains.
  • Take Lessons - Consider professional e-bike training courses to master safe habits like cornering, emergency braking, and low-speed maneuvers.

The higher speeds capable with e-bikes are a major advantage but also require more responsibility from riders to properly assess risks and ride defensively. With the right precautions, you can safely enjoy that extra velocity.

How to Balance E-bike Speed and Battery Range

How fast you ride has a direct impact on your e-bike's battery range before needing to recharge. The harder the motor has to work, the quicker the battery drains.

At higher speeds, the motor draws more power from the battery to maintain that velocity and overcome wind resistance. Going 15 mph requires around twice as much battery output as 10 mph.

So, if you frequently max out the 15.5 mph assisted speed, your e-bike's battery will deplete much faster compared to riding at lower speeds of 8-12 mph.

For example, an e-bike rated for 40 miles of range at 12.5 mph may only achieve 20-25 miles of range when ridden flat-out at 15.5 mph consistently.

There are a few ways to maximize your range:

  • Use lower levels of motor assistance when possible to reduce battery drain.
  • Avoid going at the absolute top speed except when necessary.
  • Adopt an energy-efficient riding style - accelerate gradually, and maintain constant speeds.
  • Ensure your battery stays in good condition through proper charging habits.

For casual riding, you'll likely want to prioritize battery range over outright top speed. But for commutes or applications where sustained high speed is required, you may need to invest in a larger capacity battery.

Most quality e-bikes allow you to check the remaining battery charge. Pay attention to the levels and learn how your riding style impacts the range. Finding the right speed vs range balance is key.

the e-bike's battery

UK Local Authority E-bike Rules for Trails and Parks

While we've covered the national 15.5 mph speed limit for e-bikes in the UK, it's important to also be aware of any additional local rules when riding on trails, paths, and in parks managed by councils or local authorities.

Many public spaces have their own policies that e-bike riders must follow, such as:

  • Lower Speed Limits- Some trails may have a 10 mph or 12 mph maximum speed imposed, lower than the national limit.
  • Helmet Requirements- Helmets may be mandatory for e-bikes, even if not required on roads.
  • Access Restrictions- Certain trails or areas could prohibit e-bike access entirely for environmental/safety reasons.

You'll typically find these local rules posted on signs at trail entrances and in park guidance. But it's always best to check online guidance or contact the local council if you're unsure about e-bike policies for a specific area.

When permitted on shared-use trails, ride at an appropriate low speed and yield to pedestrians and traditional cyclists. Don't assume you can automatically ride at the maximum assisted speed in those settings.

Local authorities implement tailored e-bike rules to balance access and keep trails safe for all users. Make sure you understand and follow all regulations for whichever parks and trails you'll be riding.

By avoiding the overlap with national regulations, this revised section now focuses specifically on local-level rules that e-bike riders need to be aware of. Let me know if this helps differentiate the content better.

Be a Responsible E-Bike Rider

Ultimately, an e-bike is a vehicle that requires responsible use, similar to a car or motorcycle. Riding too fast puts you and others in danger.

As an e-bike rider, you have a responsibility to:

  • Obey Traffic Laws- Don't consider your e-bike as a regular bicycle. Obey the same traffic laws as other vehicles when riding on roads.
  • Give Way to Pedestrians- Be cautious around pedestrians, especially children and pets. They may not hear you approaching at higher speeds.
  • Never Ride Under the Influence- Alcohol and drugs negatively impact reaction times. Don't take the risk of riding while impaired.
  • Use Proper Lighting- Have front and rear lights on at all times, day and night, to increase visibility.
  • Wear Safety Gear - A properly fitted helmet should be worn every ride, with no exceptions. Bright/reflective clothing also helps drivers see you.
  • Ride Predictably- Don't weave between lanes or make erratic motions. Use hand signals for turns. Follow the rules consistently.
  • Adjust for Conditions- Rain and wind impact braking ability and stability. Reduce speed in poor conditions.

The key is making safe, responsible decisions as a rider - not just riding as fast as possible. Find the right balance of speed and control.

E-bikes are increasing in capabilities every year. But with that increased power comes increased responsibility to command that power responsibly for your safety and those around you.

Become a law-abiding e-bike owner
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