Electric and Gas Assist Motors


Richard asked:

I own an electric bike and want to also add a gas powered motor. Would I still be protected under electric bike laws? And what restrictions concerning cc size, top speed, and bhp would I be looking at?


See the posts under Motorized Bicycles in the tag cloud.

Electric assist bikes are legal if they meet the statutory definition of bicycle.

Gas engine assist bikes are not legal on the highway.

If you have both and are only using the electric assist motor, it would seem to be legal, since you are only carrying an object as you would a package strapped to the bike.  But as you will see from the posts, the answer is not clear.  Before doing that, I would check with the local police.

Actual use of the gas-assist motor on a bicycle for power on the highway is clearly not legal.

10 Comments on “Electric and Gas Assist Motors

  1. I see these things on the on a fairly regular basis, not on a daily basis, but a fairly regular basis. And I’ve always wondered about them. I even see them every now and then on The Pinellas Trail.

    Sadly I even see scooters with a license plate on The Trail. I usually tell them that they don’t belong on The Trail and to get off of The Trail. After we pass each other I’ll stop and call the non-emergency police number to report them.

    One such rider tried to explain it as he was looking out for his safety, obviously forgetting that he is now endangering the safety of all those who are using The Trail. He also further tried to explain it by saying that plenty of police have seen him on The Trail and never said anything to him.

    One would think that the fact that:

    A) there are signs all along The Trail that make it clear that motorized vehicles aren’t allowed.
    B) that his scooter has a license plate, and he needs a license to drive it, as well as presumably he needs insurance

    That he isn’t allowed on The Trail while driving his scooter. If one were pushing a motorized scooter, would they then be allowed on the various trails that prohibit motorized vehicles? Also, if those has powered “bicycles” aren’t allowed on the road, where besides private property are they allowed?

  2. ” …. where besides private property are they allowed?”

    Nowhere. That is the subject of the post on gas-assist bicycles.

  3. I saw in another forum where it was suggested instead of using a gas motor ,that you use a gas generator to provide electrical power to re-charge a battery which powers an electric motor. Is this still a questionable area? Also are there any actual vehicles on the road like this? Any links to more info would be appreciated. Richard L.

  4. If that battery powered bicycle meets the statutory definition of “bicycle” it would be legal since it would be an electric assist motor that is actually powering the bike. A gas generator could be used to charge the battery if it can be done safely. You will have to research dealers for the bike you need. Easier to just plug the charger in a wall socket though.

    • That was my thinking too…..
      Gas powered generators are typically 30lbs. or more, large and square, and would not fit on a bicycle anyways..
      My suggestion would to just buy a larger battery or supplement the one you already have….
      My e-bike has a large (48v 30Ah) battery and given a top continuous speed of 20mph, I get somewhere in the neighborhood of 70+ miles out of a single charge.
      That’s 3 and a half hours constant riding…. At that point (and even WAYYY before that-like 30 miles into it), you’ll need to give your nether regions a break, anyways.

      Until they change the verbiage in the statutes, electric powered motors are the only allowable non-human power source and only up to 20mph.

      I’ve ridden on one of my friend’s gas bikes and even his 25cc motor (tiniest you can buy) goes above 20mph (top speed I got out of it was 24mph) so even IF they allowed gas motors, there’s no real way to cut the speed down to 20 anyways.

  5. I’ve seen that before….
    It’s not quiet by an stretch of the imagination…
    I’ve heard it ride before. Very loud.
    It works well..
    It’s legal..
    BUT… Its more expensive then if he just got a bigger battery.. (In both equipment costs and “refill” costs..)

    Ultimately, that generator cost $900 and the “Marine Charger” another $150…
    (and don’t forget about the cost of fabricating the setup for the connections and setup)

    For less than that price, he could have bought a 36v 50Ah battery (about $800), gotten 100 miles per charge and be able to go 20mph. His current setup only allows 16mph.. (FYI, you can get 130 miles out of a 36v 50ah battery at 16mph..)

    If you’ve ever ridden an electric bike more than 35 miles in one “sitting” (like I have), you NEED a break for at least 30 min.

  6. Thanks for the advice Geo and E-biker. I am new to E-biking and thinking of buying a trike, possibly recumbent, and then as I save money basically building my own E-bike with appropriate batteries. Any advice for a beginner?

  7. The only (relevant) suggestion(s) I have, is sticking with a 24v system or if you’re going to go with a 36v system, make sure you purchase a Cycle Analyst, as maximum allowed speed for an electric bicycle is 20mph (unassisted-Motor Power alone).
    24v system will net you from 16-18mph top speed and with a 36v/cycle analyst, you can put a “speed limiting” function into place…
    If you wish to know more, ask Geo to send you my email address and we’ll go from there…

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