Use motorcycle parts or bicycle?

[Desertprep]

I am fascinated by many of the people who are posting on this forum. Most are trying to "push the envelope" in one way or another. Most recently I have been reading about transmissions and gearing - how to get more speed or range out of a given motor/battery combo. Most of the posts that I have read are trying to push a lot of power through bike gearing systems - IG hubs, Nuvinci, etc. Many people have discovered that these things fail when put under the kind of stress that the rider wants out of them. I know that the bike parts are an easy choice because they are usually light weight and were designed to be bolted onto a bike or into a wheel. Motorcycle parts are probably heavier and maybe a little more specialized than bike parts. Still, has anyone done any calculations - especially re: transmissions - as to how much power a bicycle tranny can handle and when to call it quits and look for a lightweight motorcycle part?

 

[stanz]

Are you trying to build an eBike or a motorcycle?

For an eBike I don't see why you would need a transmission. You can't legally go faster than 20mph anyway. I guess if you were trying to use a 250W motor a transmission might be a good idea. The bike stuff should be able to handle that since that's close to what human power equates to.

For a motorcycle, it's been done both ways. Even Tesla Motors started out using a transmission until they built a better motor.

 

[wheelbender6]

Motorcycle parts a generally much heavier. Stick to higher quality bicycle parts for durability and low weight.

 

[Desertprep]

Motorcycle parts a generally much heavier. Stick to higher quality bicycle parts for durability and low weight.

I guess what I am trying to do is somewhere between a motorcycle and a bicycle but some of the motorcycle parts are a little tempting - especially the motors

 

[stanz]

I guess what I am trying to do is somewhere between a motorcycle and a bicycle but some of the motorcycle parts are a little tempting - especially the motors

Where are you located? Like I said earlier here in the USA we're limited to 20 MPH on an eBike, 25 MPH on a moped, anything else is considered a motorcycle.

 

[CVillalobos]

I wanted to build an emotorcycle before I compromised for an ebike. Here are my reasons:

Here in Idaho the laws are vague for motorized bicycles. A moped is allowed to go 30mph and a motorized bicycle could be considered a moped. So I've been riding my ebike at 30mph.

As for emotorcycle vs. ebike. You will have to title, register, and buy insurance for a motorcycle. And if most of your riding is around town than you probably can't legally go much faster than 30mph anyway. These next statements are in the legal gray area: Because of the stealth factor of an ebike you can get away with riding on sidewalks and "green belts", places a gas powered bicycle would be too conspicuous. Here in Idaho bicycles can cruise through stop signs and stop and go with stop lights and an ebike looks a lot like a regular bike.

For around town, an ebike is cheaper to build and maintain and does as much and goes more places than emotorcycle can. If I ever do build an emotorcycle it will have to be able to use the freeway system and have enough capacity for 80+ mile rides.

 

[stanz]

Boy, you've got it easy in Idaho. If you build an eMotorcycle in Ma the easiest way is to convert a gas motorcycle to electric. You must have the title for it or you can stop right there.

If you are building one from scratch you need receipts for ALL the parts and you can't use anything not rated for highway use. Then you need to get it inspected, I'm not sure who would be qualified to inspect a newly constructed eMotorcycle around here.

So, basically, we all ride eBikes or convert motorcycles with titles. That's one of the reasons I decided to go eBike, too much red tape.

I actually have an old bike in the shed in case I decide to take the plunge someday. (Yeah, it's got a title.)

 

[CVillalobos]

Boy, you've got it easy in Idaho. If you build an eMotorcycle in Ma the easiest way is to convert a gas motorcycle to electric. You must have the title for it or you can stop right there.

Maybe I misspoke; here in Idaho you would likely need a titled chassis for an emotorcycle also. I just never got that far once I added up the expenses for a performance that would only be slightly better than an ebike.

So, basically, we all ride eBikes or convert motorcycles with titles. That's one of the reasons I decided to go eBike, too much red tape..)

I guess we are thinking the same way on this subject.

I actually have an old bike in the shed in case I decide to take the plunge someday. (Yeah, it's got a title.)

I'm in the same situation. I have an old RZ350 rolling chassis that is ripe for conversion. For myself, I think an ecar conversion would be more practical now.

 

[spinningmagnets]

For an eBike I don't see why you would need a transmission

Whether you are building an Ebike with low-power, mid-power, or high-power, a transmission is a big benefit whether your concern is performance or range. A battery pack will wear out no matter what type you have, but a well designed system with an appropriate trans will last decades (if you don't mind the initial extra hassle and cost).

A transmission will provide more range from the same battery, or the same range from a smaller battery.

The lower overall amp-draw also means that a medium C-rate battery is no longer stressed, as it would be on hard acceleration from a standstill with a 9C on an uphill. Even if your commute is very short, if you have a 9C, you are recommended to buy the 15aH LiFePO4 size at a minimum due to the batteries C-rate. (for 25C LiPo or better you need only buy the actual miles you want, but some builders would rather have a transmission + LiFePO4, than LiPo).

A transmission can also mean that a job can be accomplished with a smaller motor without as many motor-heat worries (just an option...)

The common and affordable 20A controller in a basic kit is barely adequate, and is often the first upgrade. With a transmission, much better performance can be had with only 20A.

For all these reasons I am preparing to use a $100 3-speed IGH as a trans for a 500W motor, wish me luck...

 

[John in CR]

Penyou,

You're in China, so you should have access to the lighter weight moto parts for very cheap. 10-20lb of additional weight means little for street riding, and if the roads are bad, then moto parts will hold up better. Plus you can put a lot more faith in the tires, shocks, brakes, etc with the real payoff in lower maintenance.

That said, if you can source quality bike shocks and suspension forks before they get some name brand label stuck on and shipped across the ocean to be marked up 10X the fair cost, then go that route.

Much depends on how you want to use your bike, because basic dependable transportation at moderate speeds is one thing. If roads are bad, then suspension is of huge importance. If you want to blast around zipping in and around traffic, ie point A to B faster than anything including motos, then keeping the bike light and nimble with properly placed battery weight is more important. If it's for off road riding and pushing the envelope, then everything is important.

Regarding transmissions, I've decided to go a bit different route, since the bike stuff can't handle the torque of an electric motor at the power I want and the dependability that I demand. A 2 speed tranny like Thud has built is an option, but giving up the silence and dependability of a hubbie is a sticking point. Instead, for about the same weight and space I can simply add a second motor for assist if I want to accelerate harder or climb a hill too steep for a hub motor alone. Then when not in use the helper motor just freewheels. This route seems to give me the best of all worlds, regen braking, silent operation, low gearing on demand for take-off and hills, and now I even get parallel drives so it would require 2 drive failures to get stuck as long as my battery has juice.

 

[Ariane]

Penyou,

Instead, for about the same weight and space I can simply add a second motor for assist if I want to accelerate harder or climb a hill too steep for a hub motor alone. Then when not in use the helper motor just freewheels. This route seems to give me the best of all worlds, regen braking, silent operation, low gearing on demand for take-off and hills, and now I even get parallel drives so it would require 2 drive failures to get stuck as long as my battery has juice.

Hi John,

I'm curious to see this set up did you have some pictures or post about it ?

Good day!
Black Arrow

 

[John in CR]

Penyou,

Instead, for about the same weight and space I can simply add a second motor for assist if I want to accelerate harder or climb a hill too steep for a hub motor alone. Then when not in use the helper motor just freewheels. This route seems to give me the best of all worlds, regen braking, silent operation, low gearing on demand for take-off and hills, and now I even get parallel drives so it would require 2 drive failures to get stuck as long as my battery has juice.

Hi John,

I'm curious to see this set up did you have some pictures or post about it ?

Good day!
Black Arrow

I'm ready to test a motor out of a geared hubbie to see how far I can push it with some proper ventilation. If I can get 2kw out of it (I think I can get 3-4kw), then it seems like the perfect candidate for a helper motor. My son and I are early in the construction of my coast to coast bike, and we're keeping our options open with a longer than typical swingarm. There's a 1650m climb in the middle of the route, and I can't put a small enough tire on the hubbie to haul the extra 60kg of batteries we want to carry up that kind of climb at the 25mph it has to maintain and sections of 11% grade.

A few pounds of helper motor has more appeal to me than taking the big hub out of the wheel and gearing it for a max speed of 50-50kph. That's because we're trying to schedule for a time of good tail winds, and given the opportunity of good wind presents we want the flexibility to push it up to 70 or 80kph on the flats.

 

[Ariane]

Hi John,

Once again you read my mind, I'm now using a 9C 2805 on the Black Arrow and so far I love this motor, but I need more torque (Off road) and the motor heat quickly at high speed, then a mid drive set up (with a MAC motor) with my 2805 can be a great idea for my next power full ebike, thank's for the clue.

I'm curious to see how it works for you, good day!
Black Arrow

 

[John in CR]

I was eyeing that 2805 too for a pair of them in 20" wheels for a blasting 2wd. Just over $400 for a pair from ebikes.ca seems like a good price. High speed...the pair are much more powerful than an X5...and almost double the surface area for double the cooling potential...plus 2wd...seems like the potential for a great trail rider as long as you're not going for air.

 

[Ariane]

I was eyeing that 2805 too for a pair of them in 20" wheels for a blasting 2wd. Just over $400 for a pair from ebikes.ca seems like a good price. High speed...the pair are much more powerful than an X5...and almost double the surface area for double the cooling potential...plus 2wd...seems like the potential for a great trail rider as long as you're not going for air.

Hum.... interesting and you just need (2) 18 Mosfets controllers for them :wink: go ahead I want to see this ebike in action

Good day!
Black Arrow

 

[Desertprep]

Penyou,

Regarding transmissions, I've decided to go a bit different route, since the bike stuff can't handle the torque of an electric motor at the power I want and the dependability that I demand. A 2 speed tranny like Thud has built is an option, but giving up the silence and dependability of a hubbie is a sticking point. Instead, for about the same weight and space I can simply add a second motor for assist if I want to accelerate harder or climb a hill too steep for a hub motor alone. Then when not in use the helper motor just freewheels. This route seems to give me the best of all worlds, regen braking, silent operation, low gearing on demand for take-off and hills, and now I even get parallel drives so it would require 2 drive failures to get stuck as long as my battery has juice.

You also have read my mind. I am considering 2 motors as well. The first, to put on the front wheel (500-700 watts) - the new bike I am looking at has a fork that looks strong enough to handle the stress. I want to have a chain drive in the rear because of the reduced weight of the whole system and higher speeds available. I am thinking of using a front geared hub, set up for quick acceleration. I wish I could find a motor/controller that would not only do reverse but also have a "crawl" speed, i.e. can move along at 3-4 mph to navigate over objects or through crowds. When I finish with my "land cruiser" it is going to weigh more than 150 pounds w/o rider and slow speed motoring would be very helpful. I have seen some transmissions here being sold for electric 3 wheel bikes - usually bikes used to haul stuff - but they do weigh in at more than 20 pounds - that one is either a 4 speed or 5 speed. The problem for that is not only weight but also where to stick the thing! The transmissions that I have seen for motor scooters only seem to be 12 pounds or so and are a little bit more streamlined