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DIY plans for a motor in the crank area conversion

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DIY plans for a motor in the crank area conversion

Old 10-24-07, 08:22 AM
  #1  
pengyou
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DIY plans for a motor in the crank area conversion

I have seen a couple of ebikes - commercially made - that put the motor in the same area with the crank. Has anyone seen any diy plans to use this approach to convert a pedal bike?
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Old 10-24-07, 11:21 AM
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Do you mean a motor in or stuck perpendicular to the bottom bracket between the cranks or one that is right next to the cranks driving the chain?
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Old 10-24-07, 11:46 AM
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Hmmm that is a good question. I have read some articles on motorcycle design and one of the principles I read was that weight should be kept as low as possible and preferably evenly balanced between the wheels, with some adjustments based on handling requirements. I was thinking if the motor could be placed in the crank AREA it would meet both of these requirements and even be lower than the hub motor. that is the reason for my question. To answer your question - that is what my question was Which one, if any, of your two options is feasible? Which one would be the easiest to pull off? Are there more than these two options?
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Old 10-24-07, 12:58 PM
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There is the cyclone kit which mounts under and behind the bottom bracket although if you do it their way you have to replace the cranks with a single gear freewheel crank.
I have seen another kit (not sure if it made it to sale though) that has the motor in front of the cranks and looks like it attaches to a IFS crank so you still have your 2-3 gears up front and it drives another gear a little outboard of that.

The one that goes perpendicular into the Bottom bracket uses some planetary gears I think I'm not sure if it was a kit or just a finished bike. Those are the ones I have seen I'm sure there could be more.

Are you planning on racing the bike? I mean at normal bicycle speeds as long as you don't have a 10lb+ motor + batteries on a rear rack there shouldn't be any problem for regular bicycle use. Even thsoe with high mounted stuff are only an issue when getting on/off a bicycle. Motorcycles are a little different since many of weigh 10times what a bicycle weighs and more often then not weigh more then the rider so weight probably matters a bit more.
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Old 10-24-07, 03:04 PM
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These guys are between versions at the moment but their new system sounds awesome.
https://www.elationebikes.com.au/category1_1.htm
This one shows lots of pretty pictures and sells the required bits to diy.
https://www.users.bigpond.com/solarbbq/cheapdiybike.htm

Sample
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Old 10-24-07, 06:49 PM
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Way cool! Thanks for the link! No, I don't plan to do any racing but I tend to carry a lot of weight on a bike. With my present ebike the 35 pound battery sits on the front tube. I have found that control is actually easier if someone is sitting on the back which tells me that there is a serious balance problem.
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Old 10-24-07, 10:52 PM
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BB drive is the only way to go for IMO for steep loaded hills because you still get the higher speeds on the flats as wel as crawl up anything with the right gearing.
Cg. wise my experience says the lower you can put all the weight the better and preferably not at the ends.
The above also makes handling the bike when off it easier, but the bike improves when riding as well at low and high speeds.
Been there done that with the higher mounted batteries etc. never again.
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Old 10-29-07, 03:54 PM
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I'm using a bionx right now, but, of course, I still want something lighter and faster.

The hub motors limit you on the flats and downhills. The electromagnetic resisitance effects are stronger at the higher speeds. I've tried hand cranking a bionx wheel vs a regular wheel which the bike elevated and I had a hard time making the bionx wheel go faster than 25mph.

Because the bionx wheel is in the back, you can feel the imbalance between the front and rear (esp when I even had the batter on the rear rack once).

I believe a BB drive will allow you to go faster on the flats at the same power output. And for the downhills, not only will you go faster because of the absence of any electromagnetic resistance (there was a name for this but I can't remember it now), but you will really get the benefit of coasting down with a heavier bicycle.

So I'm just waiting for someone to build the perfect BB drive system. The stuff at elationebikes look great. If they have a nice controller like Bionx, I might consider it for my next e-bike.
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Old 10-29-07, 07:47 PM
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Originally Posted by adamtki View Post
So I'm just waiting for someone to build the perfect BB drive system.
Panasonic has been building one for several years. Smooth, lightweight - couple to whatever rear gears you wish. Sadly, nobody is offering any here in USA anymore.
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Old 10-30-07, 01:08 AM
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GreenSpeed are also playing with a version with pedal torque control but at the moment it is not finalized and the brochure in their number 10 newsletter shows a single ring.
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Old 10-30-07, 07:03 AM
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What is BB drive?
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Old 10-30-07, 02:15 PM
  #12  
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BB is bottom bracket, a few types shown here:
https://www.parktool.com/repair/byreg...ageField2.y=13

BB drive transmits the motor's power through this, so as to use the bike's gears.
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Old 10-31-07, 01:37 AM
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Originally Posted by BroadwayJoe View Post
Panasonic has been building one for several years. Smooth, lightweight - couple to whatever rear gears you wish. Sadly, nobody is offering any here in USA anymore.
Sounds interesting. Do you have a link or a picture? thanks.
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Old 10-31-07, 08:46 AM
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Here's a link to the Japanese site - https://www.panabyc.co.jp/

There used to be a link to OEM description of the drive unit which Giant Lite used for a couple years. One of our regulars rides one of those with an XtraCycle frame mod.

I regularly ride a Japanese market Panasonic with this unit and while it's not gonna impress the "motorcycle" crowd - assist only - it's smooth, quiet, lightweight, efficient and very dependable.

I think the downfall for it here in the USA is the fact that it's pedal assist only. Most USA riders just wanna push/twist a throttle and head off down the road at 35mph. Trouble is, that's a big risk with frame, tires, wheels, brakes, etc. that were never designed to be used in that way.
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Old 11-01-07, 06:37 AM
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Being an old guy, we're just looking for a way to extend our range ...we like pedaling...and a way to take those short trips (12 mi) without starting up ye olde fuel burner ...Thinking Green/Exercise...15mph would be plenty of speed for me...I just want a simple system that wouldn't break the bank ... We bought a 300Watt scooter motor with built in controller and thumb throttle ...just need a way to hook it up...??? In the crank area seems perfect , but we don't have a clue about those freewheeling pedals/bottom bracket... More info for Dummies , Please...!!!!
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Old 11-05-07, 05:26 PM
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Somebody posted a picture of a mountain bike with a (probably) worm drive connecting the can motor to the BB. That may be what the earlier poster was thinking of. I like the lowering and centralizing of mass too and while it wouldn't be cheap, the ideal setup to my way of thinking would use the space just in front of the downtube for the battery pack. That would pretty much limit things to NiMh or LiPo. The motor location used by the Stokemonkey just behind the BB and driving the crank through a chainwheeel on the left side of the BB (just like a tandem does) is way cool. SM seems kind of pricey though, no Pedelec or Cruise Control and what a waste of a hub motor. Some re-engineering of the idea to use a can or pancake motor might save some weight. Still, the low end hub motor systems are pretty cheap, if the SM cost half of what it does I would say go for it as is and call it good. Even with the need to buy an Xtracycle frame ($200). It's really sad that we have to be scrounging around in forums like this for ideas but more than that, for fabrication possibilities. I have all the ideas but don't have the tool skills, paying for a one off project could cost more (much more) than a really nice used car or motorcycle. That's just wrong. There should be plenty of market for the kinds of things we talk about here.

H
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Old 11-07-07, 03:33 PM
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The bike in my sig is a BB drive built by Yamaha.



Tech stuff:



The two motors drive the crank.

Wait a minute. Does this mean I could finally have my e-Unicorn with the Elationbike BB kit?
Maybe I could start building something like this:



That by the way was the working prototype for the Yamaha Racer-01 in my sig.
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Old 11-08-07, 10:19 AM
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Originally Posted by Zeuser View Post
That keirin pacer motorbike is indeed really swell, I love it's steampunk aura. But being built out of a track bike, bb drive seems kinda pointless except to make it look badass, cause being fixXxed there's no variable gearing to be had. Ha!

Last edited by JeanCoutu; 11-08-07 at 02:43 PM.
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Old 11-08-07, 02:47 PM
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I would used a 7 to 9 speed casette back there for sure. But if I could somehow make it look like the blue bike or, if I have the money, the Black and orange one, I would not only have the BB drive bike I've always wanted but I would also have one sweet looking bike that even the pedal purists would lust over.

Kickass!
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Old 11-08-07, 05:20 PM
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Well, I gotta say I prefer the looks of the red bike, the other variations seem kinda gaudy. Some kinda plastic shell thing and brakes on a track bike, wtf? In the ABC subforum there's a thread about steam powered bikes, I've described a variation of this one that would make it look damned good IMO.

https://www.bikeforums.net/alt-bike-culture/358572-steam-powered-bike.html


I'd think that a hubmotor in a disk wheel would make for a better pacer. For example it could be made to look something like Ioannas Tamouridis' Look:



Maybe not the best application for a BB drive.
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Old 11-08-07, 05:36 PM
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Just to clear one thing up: I don't want a pacer. I want a streetable eBike that looks like the Racer-01. So a 7 to 9 gear casette in the back and all of the battery, controller and motor components hidden away in a sexy plastic shell that looks as radical as the Racer-01.
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Old 11-08-07, 11:21 PM
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come spring i could build the shell for the bike from carbon fiber or fiber glass easley. would you build the shell on the frame or make wood forms and make the shell and bolt it on?

i can even make the form with Thick aluninum window screen and epoxy over it.



does anyone have a good supplier for the bb drive? close to canada?

Last edited by karma; 11-08-07 at 11:34 PM.
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Old 11-09-07, 02:59 AM
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The best suppliers I know of in Canada are heavily geared towards hub motors, they don't really carry bb drives. In fact, BionX and Crystalyte are pretty much the only ones you can walk into a store and buy personally from what i've seen. You probably wouldn't be facing too much shipping to bring one in from outside the country though.
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Old 11-09-07, 11:23 AM
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Just a thought I wanted to throw out here about a bb drive unit: I have read people talking about how much harder it is to pedal without electric assist because you have the resistance from the motor. So, what if a person were to hook up some sort of freewheel system to the sprocket attached to the motor so that, when you are pedaling when the motor is off/out of juice, it doesn't actually spin the motor, making pedaling easier?

Just a thought.
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Old 11-09-07, 12:07 PM
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Many BB systems use freewheeling cranks
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