Class 3 e-bikes are the 28 mph machines. In the three-class system used by many U.S. states, the motor may keep helping only while you pedal, and that help has to cut off at 28 mph. A throttle is a different limit. If the bike has one, it usually has to quit by 20 mph or the machine may no longer count as an e-bike.
Federal product law is narrower than that street number. Under 15 U.S.C. § 2085, a low-speed electric bicycle needs fully operable pedals, a motor of no more than 750 watts, and a motor-only speed under 20 mph on level ground with a 170-pound rider. States then decide where you can ride, whether 28 mph pedal assist still counts as a bicycle, and whether paths are off limits.
So how fast can you go legally on the road outside your door? It depends on the class label, the throttle behavior, and the pavement in front of you.
Federal product rules and state road rules
The 750-watt cap and the 20 mph motor-only test are product rules. They govern how a bike is built and sold. They do not hand you a right to ride 28 mph on every street.
The National Park Service e-bike regulation adopted a three-class definition for park units in 2020. Superintendents can allow e-bikes where ordinary bikes already go. That park rule still uses the 28 mph Class 3 figure. Trail type still matters.
Thing is, your city can be stricter than both. State vehicle codes control licensing, bike-lane access, and whether a 28 mph pedal-assist bike is even a bicycle. Local ordinances then add path bans, helmet rules, and age cutoffs. A bike that is legal to sell under federal product rules can still be a moped on a given road.
Do not treat a manufacturer sticker as a nationwide permit. It is a starting point.
What qualifies as a Class 3 e-bike
A Class 3 bike is still a bicycle with working pedals. The motor is supposed to stay at or under 750 watts. Assistance is pedal-assist. It is not a free throttle to 28 mph.
Most states that use classes also want a visible Class 3 label on the frame. Many also want a speedometer. Strip the label or unlock the controller and you may have left the e-bike category.
| Class | How the motor helps | Typical cutoff |
|---|---|---|
| Class 1 | Pedal-assist only | 20 mph |
| Class 2 | Throttle and/or pedal-assist | 20 mph |
| Class 3 | Pedal-assist only | 28 mph |
Power over 750 watts, missing pedals, or motor help past those cutoffs is how bikes get reclassified. Reclassification is what triggers licensing, registration, and insurance in a lot of states.
Throttle limits versus 28 mph pedal assist
Class 3 speed is a pedal-assist number. You have to turn the cranks. The motor then adds power until 28 mph, then it drops out and you are on your own legs.
Throttle to 28 is the trap. Federal low-speed e-bike rules look at motor-only speed under 20 mph. Plenty of state codes follow that split: Class 2 can have a throttle to 20, Class 3 can go to 28 only with pedaling. Hold a throttle open past 20 and the bike can be treated as a moped. That can mean a plate, a license, and an insurance card.
Check the manual for your exact model. Some bikes sold as Class 3 still have a throttle that dies at 20, and that is the usual design because it keeps the motor-only speed inside the federal test. If a listing brags about throttle to 28, treat that as a warning, not a perk.
If you have ever bought a bike that ships in a 20 mph mode and then a shop cable or an app switch flips it to 28, you already know how messy this gets, because the same frame can be an e-bike on Monday and a moped on Tuesday depending on how the controller is set and whether your state even has a Class 3 box to put it in.
Downhill coasting past 28 is not the same thing. Gravity is not motor assist. The legal problem starts when the motor is still pulling after the cutoff.
States that do not treat Class 3 as a bicycle
Many states copied the three-class model and kept Class 3 at 28 mph pedal assist. A smaller group never created that category. Independent roundups of state statutes still put Kentucky, Massachusetts, Montana, North Carolina, Pennsylvania, and South Carolina in that group, along with Washington, D.C. Massachusetts may allow Class 1 and Class 2 while leaving a 28 mph bike outside the bicycle definition.
In those places a 28 mph pedal-assist bike can be regulated as a moped or motorcycle. You might need a plate. You might need a motorcycle endorsement. Do not assume the class sticker on the downtube travels with you across a state line.
California is the opposite pattern. It uses the three classes, keeps the 750-watt ceiling, and treats Class 3 as pedal-assist to 28 mph. Riders generally need to be 16 or older and wear a helmet. Local path rules still stack on top of that.
New York is a reminder not to flatten the map. It does not simply copy the 28 mph figure for every street, and city rules can sit on top of the state class. Read the state code and the city page separately.
Search the DMV or vehicle-code page for the place you will ride. Search the city too, not just the state page. Forum summaries go stale fast.
Path, trail, and park restrictions
Class 3 is a road tool. Shared-use paths and rail-trails often ban it because 28 mph is a lot of closing speed next to walkers. Many states allow Class 3 on streets and on-street bike lanes, then keep it off multi-use paths unless a local agency says otherwise.
Turns out the extra 8 mph over a Class 2 bike mostly helps on arterials, not on greenways. Traffic, lights, and junctions still set your average. A Class 3 that keeps you with cars on a stroad can be the wrong bike for a packed visitor path.
National Park Service e-bike policy lets superintendents allow e-bikes where traditional bikes are allowed. A Class 3 that is legal on an entrance road may still be barred from a trail. Ask the park you are entering. Do not copy a rule from a different unit.
Watch the signs on local paths. Posted path speeds are often 10 or 15 mph even when the motor can do 28. Breaking a path limit is a ticket problem. It is not the same as blowing the class cutoff, but you can still be fined.
Rider compliance checklist
- Confirm the bike itself: motor at or under 750 watts, pedal assist that stops at 28 mph, throttle that stops at 20 mph if there is one, and a Class 3 label on the frame.
- Open your state DMV site or vehicle code and search for electric bicycle or Class 3, not a retailer blog.
- Read the city or county rules for the streets and paths you actually use, including age and helmet rules.
- Ride a short test on flat ground and watch when assist dies. A GPS app on a downhill is not a lab, but a motor still pulling hard at 30 mph is a real problem.
- If you changed the controller, removed the label, or bought an "unlocked" mode, treat the bike as unclassified until the manufacturer or a qualified shop puts it back inside the class.
Keep the owner's manual. Police and rental desks both ask for it.
Class 3 bikes in rentals and fleets
Rental operators get hit twice. The bike has to stay inside the class, and the rider has to stay on legal pavement.
Label every frame. Put the class where staff and police can see it. If your rental software can geofence assist, use it in path-only zones. Train the desk to say Class 3 is for streets, not the river trail.
Match insurance to the speed. A policy written for 20 mph Class 2 fleets may not like 28 mph operations. Write down wattage, cutoff speeds, and the states you actually operate in. That file is what you want after a claim, not a screenshot of a product page.
to be honest, a 28 mph fleet is a poor fit for mixed pedestrian paths even when the statute never mentions the trail. Speed plus tourists is how complaints start.
FAQ
What happens if pedal assist keeps going past 28 mph?
The bike may no longer qualify as a Class 3 e-bike. States can treat it as a moped or motor vehicle, which can mean registration, a license, insurance, and fines.
Do all states follow a 28 mph Class 3 cap?
No. Many use that number as a baseline. Some never created Class 3. Others add lower path speeds, age floors, or city-only rules. Verify locally.
Can I use throttle at 28 mph and stay an e-bike?
Usually no. Throttle is typically capped at 20 mph so the bike still fits federal motor-only rules and state class definitions. Throttle to 28 is how bikes get recoded as mopeds.
Are helmets or a minimum age required at Class 3 speeds?
It varies. Several states, including California, expect Class 3 riders to be at least 16 and to wear a helmet. Your city may add more. Check the ordinance, not the box the bike came in.
Pull up the DMV or vehicle-code page for the state you will ride in, then read one local path or street rule for the route you use most. Do that before the next trip, not after a stop.