Legal implicatons of riding dual drive gas electric motorized bike

[Wolfshoes]

By accident I may have stumbled upon a more practical way of dealing with electric power on a motorbike. Having done this and studying different ways of electric drive, it appears there may be a way of adding electric drive to a gas motorbike as a way of giving it the performance characteristics of a "shift kit". This may add about 20-22 lbs to a typical single speed bike and provide superior uphill and in the wind performance while also providing a quiet urban mode while still having the range of a gas bike. I have not yet pulled the trigger on the decision to buy the components, estimated at this point to be about $600 and be a relatively easy install compared to a shift kit. Confidence is high what the performance would be like. The wild card is the uncertainty of a legal challenge of riding such a bike in the 20-30 mph range. In a worst case scenario, it may not be above reproach in legal analysis after an accident. If the legal risk is too great, it may be prudent not the make the build in the first place, even if the performance would be good. In looking at the forum history of postings, I do not see where such a bike has been attempted in the past.

 

[Steve Best]

I am looking at the same thing.
My plan is to use electric around town and anywhere I might offend someone.
On open roads I would use the gas engine to make speed and distance and charge the battery.

I am doing this already without a problem, but on 2 different bikes.
I use electric up to 20mph in town and even "bike only" paths.
I use gas up to 35-40mph in rural and inter-community areas.
No problems so far. Now to marry the two...

 

[Frankenstein]

Same considerations here, while the bike sits on the chopping block I can't help but wonder how practical it would be to equip that nice big front tire with an electric hub, and then also wondered how technical the loophole really is. By definition in my state such a bike would be both classified as an electric bike (with rights to all things purely bicycle related) and as a moped, which is considered a motor vehicle.

At which point does the line get drawn between the two. I would have to assume that because it is both (now) federally defined and defined by state law as an electric bike and defined as a moped only in state legislature then it must be an electric bike regardless of the gasoline motor, even if under power by it, at a 2 to 1 vote...

Neither one states the bike must be under power solely by electric means, it simply states that being equipped with the system is enough to define it as such, and that's in both federal and state level code.

I would say that if you exceeded the federal guidelines regarding speeds then you've automatically opted out of the federal protection and so if caught red handed you'd be subject purely to state law.. At that point it's downhill, but if you can manage to play it smart then you could ride around a bike staying under the federally decided speed limit while under gas power and you'd have all the protection of an electric bike, legally speaking.

As for practice I couldn't even begin to guess how well it would all go.

 

[KCvale]

not yet pulled the trigger on the decision to buy the components, estimated at this point to be about $600 and be a relatively easy install compared to a shift kit.

Don't be so sure, once you get into batteries and wiring it's a whole different world.

 

[5-7HEAVEN]

"This may add about 20-22 lbs to a typical single speed bike."

You were right; my gas engine added about 22lbs. to my other bike.

My 72vdc electric motor, controller and lead batteries added 80lbs. to my 45lb. bike.

I also thought of building a hybrid.

I just didn't want to deal with a bike that weighed 145lbs.

FWIW, my present mb weighs 70lbs.

 

[KCvale]

My 72vdc electric motor, controller and lead batteries added 80lbs. to my 45lb. bike

Running LA batteries on an E-bike is tough, thats why most people including me run LI batteries.

 

[Steve Best]

Running LA batteries on an E-bike is tough, thats why most people including me run LI batteries.

Plus with a gas motor on board, there is much less need for electric range.
You only need enough battery for around town, probably no more than 10 miles max.

Gas motor including tank = 20 lbs
3 x 12v 8ah batteries = 8 lbs
250w geared hub motor = 6 lbs
Controller and all wiring = 1 lb

About 35 bs total, less than my present 12 ah SLA batteries weigh...

 

[5-7HEAVEN]

Plus with a gas motor on board, there is much less need for electric range.
You only need enough battery for around town, probably no more than 10 miles max.

Gas motor including tank = 20 lbs
3 x 12v 8ah batteries = 8 lbs
250w geared hub motor = 6 lbs
Controller and all wiring = 1 lb

About 35 bs total, less than my present 12 ah SLA batteries weigh...

So I guess that "3 x 12v 8ah 'non-leaded' batteries" helps break the OP's $600 budget.

 

[KCvale]

You only need enough electric power to get you going fast enough to start your gas engine hehe ;-}

 

[5-7HEAVEN]

You only need enough electric power to get you going fast enough to start your gas engine hehe ;-}

Yeah, you're right.

How much electricity would you need, and how much would it weigh and cost?

You've built e-bikes, so you've got the knowledge, KC.