Safe, street-legal 45 mph e-bicycle possible?

[JohnT818]

I have a lot of projects I'm considering, and I'm trying to figure out what makes sense and what doesn't. I don't know much about bicycles, and I was hoping people here could help me out. I'd like to build a safe, street-legal, electric bicycle capable of 45 mph. Is this reasonable or would it make more sense to covert a motorcycle? The two things I'm most concerned about are the brakes and tires. And, I'm not worried about what I can get away with. I want my bike to comply.

First, the tires. To be street legal here in California, I think I'd have to register a vehicle capable of 45 mph as a motorcycle. As a motorcycle, I think I'd have to have DOT approved tires on it. I doubt there are DOT approved tires available for bicycle wheels. Am I right? Do I have options? Moped wheels and tires? Is it doable? Would they be safe at 45? I don't mind searching an appropriate donor if necessary. I don't weld, but I don't mind learning or having someone else to it for me. Any suggestions?

Now, about brakes. If I convert to moped wheels, I assume there's some way to incorporate moped brakes, too, right? Would that be difficult? If DOT tires can be mounted on bicycle wheels, what would everyone suggest as a brake system sufficient for a 45 mph ebike? I've heard about disc brake conversions but don't know anything about them. Maybe someone can point me to a web page or something.

Also, do I need to get special bearings to handle sustained high speeds? And would both front and rear suspension be a good idea? Any advice on drive systems would be appreciated, too, but there seems to be a lot more info available on that topic.

Oh, and I realize there are other regs I'll need to comply with, lighting for example.

 

[Drunkskunk]

a 20 inch bicycle tire and a 16" motorcycle rim are only a millimeter off in size, so you can mount 16" motorcycle tires to 20" bike rims.
High end disk brakes are capable of stopping a bike coming down the side of a mountain at greater than 45mph. But Bicycle disk brake pads wear out in 1000-2000 miles of pedal speeds, so expect them to need replacing often.
Full suspension is almost mandatory at speeds above 35mph, as even the impact of small bumps at that velocity can kick the wheels up off the pavement.

Plenty have done it. Making it safe is the challenge. Mostly whats needed to make it safe is enough experience to see where the line is, and and to know how far you can push each part of the bike past that line before it fails.

 

[amberwolf]

The only problem I see with it is "street-legal". In California a bicycle can't go faster than 20MPH or it isn't a bicycle anymore. That's true in many places in the USA, including here in AZ.

If you want to do faster than that, you might want to find the recent thread about California ebike laws, which has some links to the motor vehicle code there, and might help you figure out exactly what kind of vehicle you have to start from.

I suspect that for registration reasons, it'll be easier to start with an existing motorcycle frame with VIN, even if you chop it up and keep the parts with the VIN on your custom build.

 

[dogman dan]

I agree that street legal is going to be the problem. You will have to create a vin number to register it, so look into that before you sink money. I think starting out with a street legal motorcycle or scooter frame and converting it is the way to go. That way everything is built for 50 mph, and it already has a vin number.

A 45 mph dirt bicycle for off road is another story altogether, or could be ridden on the street at ebike legal speeds untill you have the road to yourself, when you could hammer the throttle and fly.

 

[AussieJester]

If you want a solid frame built get in touch with Travis from Iron Spade Cycles he builds
heavy duty frames capable of those speeds safely... You can get hold of him on
http://www.ratrodbikes.com/forum/...his nick is (IronSpadeCycles)hes in Port Alto/Austin/Houston TX (sorry no idea how close that is to California?)
Theres a couple of threads on going on Ratrods with his builds if you want too see his work.

Best of luck

KiM

 

[IronSpadeCycles]

Alright well Kim clued me in to your build idea and I have a few questions for you to sort of clarify your intentions. This is Travis with Iron Spade Cycles, I've been a custom motorcycle and bicycle builder since 1996. Although I specialize in building high-end custom bobber's and choppers from Norton, Triumph and older HD's I have been know to build complete one of a kind concept bikes as well. You name it, and I can probably build it. Alright enough about me.

I have a few suggestions for you but first we need to see what is your budget? I know it always comes down to money, but lets face it nothing in life is free. Most of the new off the showroom floor E-Motorcycles I've seen are priced around $10K. I think we need to stop calling your project an "Electric Bicycle" and just call it what it will become, a lightweight E-Motorcycle. I think that with the right components This bike could be built into a safe, street legal, capable of 45mph and still be stylish for somewhere in the area of $6000. That would save you a bit of cash and if you didn't mind an open ended time line you could very easily finance it over the course of the build.

I guess the biggest hurdle your face with is deciding what your ultimate goal really is. Like I said before, I can build anything, but you have to decided what its really for. Are you simply trying to get around the city streets in you town with an average of say 10 mile commute? Or are you planning on using this as your primary fair weather transportation and need more range, power and overall top speed? Are you heart set on Electric versus Gasoline?

I think wheels and brakes are the easiest problems to solve. Light weight, motorcycle alloy rims can be had as well as light weight small motorcycle tires DOT speed rated for 70mph. I own a mill and a lathe and have made several one off hubs for both motorcycles and bicycles so that really is the least of the problem. The frame and suspension are also rather easy to tackle, and I totally agree that it must be full suspension! We can build you something that looks like a real motorcycle, like a slimmed down super motard, or we can build it to look like an electric bicycle on steroids. I could even design and build it to look like a 1930's Thor or HD.

The real limiting factors and the most influential on overall price will be the power source. Just to give you a ball park, if it cost $1500 to do a sustained top speed of 20mph, its going to cost you over $6000 to do a sustained top speed of 45mph. About 4 times as much to go twice as fast. The golden rule, and everyone here will tell you the same thing, Speed Cost Money, its just a matter of how fast do you want to go. As speed rises cost go up exponentially. The other factor is range. Just remember this, higher speed= lower range for a given system. If you design a system for 40mph top speed but you only ride it at 25-30mph most all the time your range will be good, but if you dog it all the time your range will suffer, a lot! You can increase battery size and capacity for greater range but you are ultimately adding more weight which will put more load on the motor, draw more current and ultimately slow you down more. Sure you will gain speed and range but the amount will not be exponential. Twice the battery does not mean twice the range.

Now the upfront cost will be greater, but if we design a system for a real time top speed of say 55mph, knowing your intention is to only ride it on city streets where the average top speed will be 35mph you bike will have good range and overall performance. Just because you can go to legal highway speeds doesn't mean you should travel on the highway. I've got a buddy in Denver CO who recently finished building his Honda Rukus scooter to do over 70mph. It has cost him almost $9000 so far.

I guess this really does come down to your budget, what your intentions are, and how much skill and effort you want to put into a project like this. I could do a complete build for X amount of dollars or I could make components such as wheels, frame, suspension and bodywork and you could assemble the components yourself. If you would like you can email me off site, or we can communicate on here.

I guess you now have to do some pondering to do. Talk more soon. Later Travis

 

[johnrobholmes]

It is possible, but you will need a VIN for california. Maybe you could start with a Moped frame?

 

[IronSpadeCycles]

Here are the requirements for CA to register a homemade vehicle. Since your planning an E-Vehicle, the SMOG check won't be applicable. It looks rather simple to do! Don't waste your time with a moped frame, its not needed.

http://www.dmv.ca.gov/vr/spcnsreg.htm

Later Travis

 

[johnrobholmes]

Depends on how it gets built, and who is putting the time in. It may be worth the OP's time to start with a title, but it depends on how custom he wants to get.


You will likely have big troubles getting a VIN on something that looks like a bicycle, especially if it has an ID on it from a bicycle manufacturer. I know in ILL they refuse to title mopeds with bicycle frames.

 

[JohnT818]

Thanks for the info, guys. I really should've thought of the VIN! I'm somewhat familiar with SPCNS regs for cars. I'll have to look into what I'd need to do for a bike. Don't know if using a bicycle frame would be a problem, but I hear converting dirt bike frames to street use can be a problem in California. By the way, I'm in Los Angeles County. KiM, from me to Houston is about 1500 miles (2400 km)!

Yes, Travis, you're right. I should think of it as a light weight e-motorcycle, but for some reason, I feel better thinking of it as a fast bicycle than a slow motorcycle. I guess I should just get over it. I'd like to keep it closer to bicycle weight than motorcycle though.

Thanks for the offer to build it. I'll keep that in mind, but I'm hoping to do it myself and learn from the process, although I might want to job out some of the work. If I come up with a plan and want to get into more detailed pricing, I'll contact you directly.

In the meantime, let me answer a few of your questions. I'm only interested in electric. I have an ICE Ninja 250 already. Actually, 2 of them if you include my wife's, which she never rides anymore. I might convert one, but I'd like something smaller and lighter. My commute is under 4.5 miles each way, so I'm not very concerned with range. I could just go with a 20 mph e-bicycle, but I'm more comfortable flowing with traffic than trying to keep out of it's way, even though there are bike lanes on most of my route. Most of the streets I use are straight and pretty level and 2 or 3 lanes in each direction. Speed limits are mostly 40 mph, with traffic flowing around 45 or 50. I'd like to mostly go 40 with the ability to up it to 45 if I feel I'm slowing people down.

As far as configuration goes, I'm not sure. I like the look of streetfighters, which are kind of like naked, stripped down sportbikes. Lately, I've been really intrigued by recumbent lowracer bicycles. If I went that way, I'd definitely go longer and higher than most. Maybe between a lowracer and a CLWB recumbent.

I haven't thought too much about budget, but I figure roughly $3500 or so for EV parts (batteries, BMS, motor, controller, DC-DC converter, charger), plus a few hundred for brakes and lighting. $6k for a custom build sounds pretty reasonable to me. I don't want to spend that much, but it doesn't sound bad considering I'm probably over $4k just for parts.

Alternatively, I'm thinking about doing a reverse trike, but it would be bigger and heavier, need more motor and batteries, and cost a lot more, but that's a whole 'nother thread!

 

[AussieJester]

My current build is probably pretty close to the specs your after, should come in tad under 45-50kilograms (100-110 pound) when complete so heavier than your 'normal' bike but a hell of alot stronger. Might get a few ideas from it possibly link to worklogs in my sig..

Best of luck

KiM

p.s so your about as far away from Travis as Perth (where i live) to Adelaide ... half way across the country

 

[liveforphysics]

IMO, the single greatest thing about an E-bike, is the "Bike" part.

As a guy who has 3 street legal motorcycles, I recognize the unique qualities a bike can have over a motorcycle.

Bike path legal
Bike rack legal
Bike lane legal
Legally not called a motor-vehicle
No inspections
No insurance
No registration


Also, getting pulled over for speeding on a bicycle would be a minor traffic ticket.

Getting caught swapping VIN numbers around is a federal offense. Its one of those major things you're really going to wish you didn't get caught doing.


My downhill E-bike can do 64mph (gearing limited), and holds over 45mph going up hills. The brake disks turn neat colors, and the pads do wear, but they are cheap and easy to change, and they always still function.

It is squirly doing 60+mph on a downhill bike, but 45mph isn't that bad.

You only need to go as fast as you want, when you want. Just because you're got speed, doesn't mean you can't ride like another E-bike when you want to take things easy.

 

[IronSpadeCycles]

To some extent, advice is always free. I primarily build motorcycles and cruiser bicycles for a living and all my work tends to be one of a kind customs. That being said my bicycles range from around $2000 to over $6000 depending on materials used and extent of overall finish. IE carbon, titanium, alloys, exotic finishes, etc... Motorcycles start at about $10K and average about $25K. I've been an accomplished welder and fabricator for the better part of the last 15 years.

You stated early on that you knew little about welding and fabrication but would be willing to learn. My suggestion, learn to weld by making a table or a piece of art, not something you could die on if your weld failed and sent you into oncoming traffic. I did say about $6K for a complete bike before knowing exactly what you had in mind for the power source. Just to give a better idea, a one off custom light motorcycle chassis will cost more into the $3500-$5000 range if it is entirely built by someone other than yourself. The biggest problem I see with your plan is you want something that either doesn't exist or can't be made for the money you want to spend. Sweat equity goes a long way towards lowering the overall cost. $6K is with a lot of sweat equity! If you had a few years of mechanical experience in fabrication then I'd say jump right in and start building. I'm 41 and I learned to weld when I was 16. I didn't trust my welds to save my life until I had at least a couple of years of practice.

You know what your up against with the local DMV. Forget using a bicycle frame for any sustained speed over 35mph, especially in LA traffic! Its a death wish at best. I know I lived in OC for 2 years and rode a motorcycle 25 miles to work everyday. If your really on a budget and can compromise with your design, I'd suggest looking on Craigslist or locating your local parts yard and find a decent condition late model rolling chassis from a small cc motorcycle for several hundred and just do a conversion. That way you can sink the majority of your budget into high end lithium batteries and high powered motors. It might not be want you really want, but it will save you a ton of cash on the front end. Your still going to need to learn to weld and fabricate a lot of parts, but you won't necessarily need to worry about your welds failing on the frame or the suspension. Do you have a proper garage to build in with really understanding neighbors? I can almost garrantee someone will call the cops if your using a grinder every evening for several hours.

You said you want to cruise at 40mph with a peak of 45mph, that can't be done on a bicycle chassis, not safely anyway. Also you want it to be light weight, well without the highest grade of Lithium batteries (IE most expensive) that won't be possible either. Your also going to need a range of at least 15 miles at 40+mph. I'd figure about 125 lbs for a used light weight motorcycle chassis and another 60-75lbs for the motor, batteries and controller. Trust me a 200lbs motorcycle with about 6-10HP will feel a lot lighter than your Ninja 250. It won't be like a heavy 90-100lbs bicycle but it will track a lot better in traffic as well as handle bumps in the road. It's always going to be a compromise unless you can spend the time and money to build it with the lightest components, and the best power source. For about $10K you could have exactly what you want; light weight at about 140lbs, high power and a fair amount of range. Also rapid recharge depending on you power source, 110v vs 230v. But then again you could buy a showroom model for that.

Alright well I think you know whats up. Good luck and I hope it all goes as you want it to.

Later Travis

 

[liveforphysics]

I'm moving on to my 100mph bike project.

I'm willing to sell my 64mph bike.

$2,500 for everything but the battery setup. $3,500 with the battery setup/charger enclosure. Total bike weight is currently in the 75lbs area with the current controller setup.

Chargers at full tilt are able to do 2,200w (if you've got them plugged into separate breakers on 110VAC, or if you have a 220VAC connection).

I might make a for-sale thread. If I don't find a buyer quickly, I'm trading to a guy for a badass CNC machine setup, which will help me to get my 100mph project bike done with a lot less effort on my part.


IronSpade's advise about not learning to weld on something that is critical to not fail is very good advise! My dad (professional metal welder/fabricator) started me welding when I was in 2nd grade, and I still learn new techniques and tricks 20 years down the road.

 

[johnrobholmes]

I should think of it as a light weight e-motorcycle, but for some reason, I feel better thinking of it as a fast bicycle than a slow motorcycle. I guess I should just get over it. I'd like to keep it closer to bicycle weight than motorcycle though.

It is just semantics. Realistically (and legally), you want a light motorcycle. Conceptually and parts-wise, it will be closer to an e-bike/ Moped to hit your target weight.



My current project is basically what you want. 45mph top speed, under 30 kilos, and DOT tires. http://www.holmeshobbies.com/blog/?page_id=20 If I gear it for 30mph on the streets then I don't need registration. Unfortunately Cali is stricter and you will need to plate it. 15mph limit for "scooters", 20mph limit for "ebikes", and 30 mph limit for "mopeds" which need plates/ vin (one time charge). Above this you are technically a motorcycle by law.

 

[IronSpadeCycles]

Holmes, that's really cool but have you cornered the market on Santa Cruz mtn bikes? If some Joe was to take your lead, he'd spend $3000 just on the bicycle. You say the tires are DOT, what kind are they? And a huge suggestion on your frame clamp. Never use nuts as weld-on threaded inserts, they are too weak to take any stress loads and after welding they distort and work harden and become potential failure points. Check out "Bung King" for threaded bungs http://www.bungking.com/osc/index.php?cPath=15&osCsid=73319535e351998088b9411b49cf4ef5

They should have what you need to make that frame clamp bullet proof.

Later Travis

 

[johnrobholmes]

Lol, cornered the market? I just have a few of them here. Thanks for the tips on the bungs, I will certainly go that route. The mount won't work as I expected so I am redoing it anyway.

I am using Shinko 244 tires (motorcycle) and michelin gazelles (moped) on 17" motorcycle rims.

 

[mrzed]

I'm generally in agreement with Travis there.

IMO, more than 30MPH/50KPH cruising speed on anything bike is asking for trouble. Full suspension helps, but good strong full suspension bikes are almost universally designed for pointing downhill offroad. Road riding is a different set of handling dynamics. Oddly, road motorcycles are designed for these conditions and speed.

The advantage of an eBike is that it is a bike. Pushing the speed envelope gets you an unlicensed, illegal, likely unsafe (though this is clearly all relative) electric motorcycle.

If it was me, I'd be saving my pennies for a professional custom fab job, or looking for a 125cc sportbike donor. I figure these are the best conversion candidates, as they are built for speed, lightweight and good brakes and better safety at speed than scooters.

 

[amberwolf]

As a guy who has 3 street legal motorcycles, I recognize the unique qualities a bike can have over a motorcycle.

Bike path legal
Bike rack legal
Bike lane legal
Legally not called a motor-vehicle
No inspections
No insurance
No registration

You forgot the ability to pedal home when your experimental badass motor/battery/controller explodes.

 

[IronSpadeCycles]

Not to sound too overly cynical but...

Look here's the deal, and well, the unfortunate part of the BIG government that we're getting more and more every day.(Thank you Obama ) Ever since the early 20's inventing young types have been putting surplus chainsaws and old lawnmower engines on bicycles for fun and to help them get around their communities. There were no laws governing motorized bicycles until the early 80's. Then up until the mid 90's any kid that could pedal a bike could ride a moped all over town, without a license or registration, but that has also come to an end. In my small coastal community everyone drives golf karts around the neighborhood even though the closest golf course is over 40 miles away. Everyone in this town is breaking the law, daily as none of them are licensed vehicles and kids as young as 6 are seen driving them all the time.

In most states, if your over 16, riding a less than 50cc scooter such as a Vespa or Honda Ruckus doesn't require a license but even that's being rectified as it becomes even more popular. Mark my words, if enough people start building and riding homemade electric bicycles no matter the top speeds, BIG government is going to see that as a lost revenue source. Before you know it all kind of laws and requirement will be set by people who've never even ridden a bicycle let alone a street driven E-bike, telling you what you can and can't get away with. Some politician is going to see one go by and think, "now why does that guy get to ride on our city streets without paying his hard earned tax dollars for the privilege?" What's next you have to be a licensed driver to ride a bicycle?

The minute BIG government gets involved you might as well start looking for a new hobby like underwater basket weaving, I don't thing there are any laws governing that yet... Yet.

Later Travis

 

[IronSpadeCycles]

Sorry John for running off with your thread, I kind of forgot where I was. I'll play nice, I promise.

Later Travis

 

[AussieJester]

I'm generally in agreement with Travis there.

IMO, more than 30MPH/50KPH cruising speed on anything bike is asking for trouble.

I have to agree here, granted high end mountain bikes like John and Luke are using are damn
solid frames and structural failure is not a concern here, what is IMO is frame geometry and length, these bikes were design for downhill use by experienced downhill riders in bumpy OFF ROAD conditions where top speed might touch 45-50mph but not be constant at that speed like e-bikes, they lack the length and head geometry for continued high speed stability, Luke even admits his bike gets twitchy at speed, but he has been riding high powered motorcycles for many many years so has experience to deal with this but for the average Joe building a mountain bike up slapping huge power on it and taking off down the street i think its begging for trouble, im amazed someone hasn't been written off already because of! You can put all the best components on it make it bomb proof but it still aint going to help the handling of it at speed.../my 2 cents.

KiM

 

[johnrobholmes]

Regarding handling of downhill bicycles on road, the front setup can be changed widely to suit handling for XXX situation. Shorter forks, longer forks, huge stem selection, and plenty of drop/rise bars to choose from. Rake and trail can be tweaked with fork selection and tire size.


IMO, it isn't the steering geometry that makes a DH bike handle twitchy at speed. They are normally set up with a relatively high mechanical trail (but maybe not enough for 50mph speeds?). It is the relatively light weight and typical handlebar positioning that can cause twitchyness. Decreasing stem length or even turning bar/stem around drag style can really help the high speed handling, of course compromising other handling characteristics.

 

[AussieJester]

The length is the major issue John, they are half a wheel too short for any form of stability at speed they are required to be nimble and responsive for their designed application ie. doging trees downhill LoL... hence the short wheelbase ..ride a bike thats a 300-500mm longer wheelbase at speed then compare it too your mountain bike and you will see the difference the extra length makes

Kim

 

[johnrobholmes]

Very good point there, WB is a good bit shorter than bigger bikes. I would like to ride a longer WB light bike and see how high speed handling gets affected.



What I would like is a "tank" I can squeeze with my legs. I rode a Dutch moped on sunday and it had a really nice feel to it. Super solid around 45mph, you could steer with your hips.