My non hub build

[flyinmonkie]

Cargo,

I like the idea of up to an 90 or even 100 tooth sprocket, but I'd have to fit a small drive sprocket to a freewheel for the motor. Or convert the rear cluster and secondary drive sprocket to the kart sprockets. Hum... maybe something to think about. Might make pedaling a challenge though.

 

[cargo]

.

 

[deecanio]

Hi fm,

it could be worth looking into what cargo mentioned and use kart sprockets for the reduction from the motor to the crank,
that way you could run a 219 chain from the motor to the crank then have standard gearing from there.
how many teeth do you have on the non motor front chainring and what gearing do you have at the back?


Cheers,


D

 

[etard]

Nice build, for a monkey! :lol: :wink:

Is it possible to reverse the spring on that tensioner, it would seem a better idea to have as much interaction between sprocket and chain as possible. So what speeds were you seeing with your test run? Maybe cheaper/easier than the Kart chain and sprockets would be to get a internally geared rear hub, or a lower KV motor.

 

[Bobocop]

Nice work so far.
since you would rather have bike parts instead of the kart sprockets as cargo suggested, what if you go with a 9 tooth at the motor and a 56 tooth at crank (biggest i could find for bikes), wouldn't that make a bit of a difference ?
do you really need a freewheel at the motor ?

 

[MitchJi]

Hi FM,

http://www.rcgroups.com/forums/showthread.php?t=963893&pp=31

On a side note: DO NOT link the motor to the crank with a bicycle chain. It WILL BREAK. Ask me how I know Use a motorcycle chain. A 520 size will work well. The bicycles main drive system can be left alone as there is less stress on that side.

Originally Posted by mjsas
I have used bicycle chain with motors up to a 2,000 watts. With smaller motors they work well but with something like a starter motor they do break. A starter motor can pull apart a link with pure torque. Also do not use master links as they are weak, I use a chain breaker and reconnect the links. Even the high strength, mountain bicycle chains will break.

Mjsas is correct. This is exactly what I meant by not using the bicycle chain for the motor side. Remember that this design might be for 800 Watts running, but peak power and peak torque will be much higher than running. I snapped a bicycle chain using a series wound winch motor on pure torque at only 12 volts just as mjsas has with a starter motor. I also agree to buy a chain breaker tool and not use a master link.

The reason this happens on the low torque side is because of the gearing. While it is true there was more torque at the wheel than the motor shaft, it was achieved by gearing. Thus at the wheel 1 lb-ft of torque could be generated with ~4 lbs tension on the chain, however on the motor side the pinion was very small and even though the motor only put out a few ft-lbs, the tiny gear converted this nearly a hundred lbs tension and overstressed the chain. Now add to that the high rpm of the motor and you have a recipe for failure.

 

[Bobocop]

Good info, maybe this is why i have never seen these motors on sale with bike chain sprockets (unless its a geared motor)

 

[flyinmonkie]

Bobocop,

I thought about the smaller sprockets for the motor, but you can't get much smaller than a 15 tooth on a freewheel and even then you need a smaller thread than most freewheels. Also, the smaller the drive sprocket the less efficient. I have seen several posts here where people have used smaller sprockets and had problems with the chain jumping because there is not enough contact between the chain and the sprocket. As for the freewheel on the motor, I think a necessity if you are going to pedal with out the motor running. Otherwise you have to drive the motor as well as the bike. Could get quit hard if you use a high power motor.

Mitch,

Great info. I've though of running motorcycle chain and sprockets on the whole thing for strength, but I don't know that it would shift on the back end with a derailleur. lol Also, I haven't seen to many sprockets any bigger than you can get for a bicycle, unless they are custom made. I may not have looked hard enough though. May be a possibility for the motor to the crank. I am running a 600w currie scooter motor, so not the power you guys are looking at running. this is my concept test bed, so I have gone somewhat simple in the workings of the drive system and want to see what I can get out of a low voltage lower watt motor through gearing. I'm not overly worried about breaking a chain and a person can generate around 500w for short bursts form what I am told. Could be way off with that too though. If I break chains I'll change the system.

I am sort of thinking a belt for the variety of pulley sizes and to quiet it down a little. It was slightly lowder than a standard bike with drive noise. Some of which may be the resonance of my diamond plate cowling. Of course I have to get a pulley attached to a freewheel or oneway bearing on the motor. It is all about tweaking the gearing now to see what it can and can't do. I am thinking about using large chainrings on the back for the motor and keep some standard smaller ones to pedal if the batteries die. All in the air at them moment. Will be interesting to see how it turns out though. I am looking forward to it myself lol.

Oh, by the way, the motor problem was a sheer pin and will be fixed by the new year. So I'll have it all back together soon and be starting to try different gearing combinations soon.

Thanks for all the ideas and help. I'll get some pics of it all together again once it is all back together. It looks a little like a 2 wheeled tank. I am trying to keep up with the RC stuff as I am very interested in that. After I sort out the gearing and put this system on a chopper bike, a downhill RC set up may be next.

FM

 

[flyinmonkie]

Well, the bile is all back together again. I know I said I'd have pics, but they aren't here yet. My partner's new house is built and has a nice new garage, so she has let me turn one corner into a bike shop. She's pretty good, I'll keep her around a little longer :lol:

Anyway, The bike is back together and slightly regeared. It is a little better, but still can't really start from a dead stop on it's own. When it gets up to speed, it is probably runs about as fast as I could pedal. I haven't put the GPS on it yet. Amazingly it never draws more than 20amps and the motor only gets warm to the touch, even after 10 min of riding at WOT. I am powering it with 2 20ah sla's and have the basic controller that came with the currie scooter motor. It is a 40 amp controller.

I guess I am still struggling with how to gear it. Here are the current specs:

24 volt motor 2600 rpm
16t drive sprocket
46t driven sprocket (at crank)

22t driven sprocket (at crank)
34t driven sprocket (at rear hub)

That is the current set up for first gear.

I would like to keep the rear hub running on bike chain and able to have at least 3 gears. At the motor and crank, I don't have a lot of room between the motor and first stage driven sprocket. I have though about using a belt to drive the first stage as it is a little loud. I am also thinking about adapting large chainrings from a crank to fit the rear hub to get larger gears on the back. I am open to ideas and input. I will have pics up this coming weekend and try to work on a video. It is fun to ride though, and I can't wait to get the gearing sorted.

FM

 

[GGoodrum]

FWIW, I've had zero problems using bicycle chain with my Cyclone 1000W setup, and it hits 2600W peaks (55A with a 16s a123-based pack...). It also has a ridiculously small 6T motor sprocket, driving a 44T sprocket on the crank. It is noiser than all get out, but the chain is holding up fine, after a 100 miles, or so.

 

[vanilla ice]

2600 rpm
16t drive sprocket
46t driven sprocket (at crank)

Thatd be 900rpm at the cranks, isnt it? Thats no load? Whats the useable rpm range? Go belt or 219 chain.

 

[flyinmonkie]

GGoodrum

That's great to hear about bike chain holding p to your 1000W cyclone. 6t drive sprocket? It doesn't skip being that small? I'd love to get down to about 10, but you can't get a freewheel that small and I want a freewheel on the motor.

Vanilla Ice,

Yup, you've got it right, no load rpm. It steps down a again from the crank to the rear hub if you are in the lower gears. It actually gets moving with a little push or a couple of pedals. It takes a while to get up to a reasonable speed, but it does get there. It doesn't have enough torque at the moment to get to a decent speed though.

I have thought about 219 chain and a belt, but I think I am going to try a 2 stage reduction from the motor to the rear wheel and not drive the crank. At least I'll start with that and see how it goes. I'm expecting it to be noisy.

FM

 

[flyinmonkie]

Well, I promised pics, so here they are. I went and picked my bike up tonight to try to sort out my gearing in my head. Always easier for me if I can look at what I have to work with.

 

[recumpence]

FWIW, I've had zero problems using bicycle chain with my Cyclone 1000W setup, and it hits 2600W peaks (55A with a 16s a123-based pack...). It also has a ridiculously small 6T motor sprocket, driving a 44T sprocket on the crank. It is noiser than all get out, but the chain is holding up fine, after a 100 miles, or so.

Heck, I've pulled 7kw though my BMX chain without problems. There are absolutely no worries with bike chains, at least BMX chains. :wink:

Matt

 

[northernmike]

Not all bicycle chains are created equal, though. I've come to trust SRAM chains in my roadbiking experience. You do get what you pay for.

 

[flyinmonkie]

It's been awhile since I've done much with my bike. Work has been busy, yadda yadda yadda.... Anyway, i am losing some interest as it has become further and further from my vision. I have some partially fabricated pieces to add a standard bike hub which will add a second gear reduction, and unfortunately and another chain. I really should push on to test the concept with this bike, but it is requiring more fabrication than I am sure I want to put in if I am just going to tear it apart and transplant everything. In saying that, I am looking at a chopper bike with much more room on it to add gear reductions and batteries. Something tells me I want to go to a 1000w motor for that though. I would love to go the RC route, but it is just a little pricey at the moment for me. Maybe with a DH bike in the near future.

Anyway, we will see how I feel this weekend and if I sort the hub for reduction for test 2. I have been planning the chopper bike almost since I started this bike and am very excited about my ideas for the drive system. No matter what, the chopper is a go in the next few weeks. My goal is to have a working bike to commute on before it gets what they call cold here in New Zealand.

FM

 

[flyinmonkie]

It was a big weekend on the bike front for me. For those that ages, ages ago now, after a test with the GPS, I got up to 30k/hr with my single stage reduction set up. It took forever to get there and any hill or head wind slowed me down considerably. I also had almost no acceleration, especially from a dead stop. Made big intersections interesting. Especially since the pedals had to be in granny gear for the motor to work at all.

So enough of history. I figured I was so close, I would sort out my gearing and see if I was on the right track. I added another stage of reduction using a rear bike hub with a cassette freewheel. This allows me to swap sprockets easily. Anyway, it hangs off the bottom of the down tube like ear flaps on Elmer Fudd's hat. Very ugly, but a huge improvement. It isn't a perfect setup and I can tension the chain from the hub to the crank as tight as it should be, but with gentile throttle movements it works well. I now have some reasonable acceleration, similar to a standard pedal bike, but in 1st gear I hit 25k/hr in about 400 meters. I haven't had a chance to give it a good run yet, so I don't know top speed. I did hit 30 k/hr though. It isn't too much louder than it was before, but I wouldn't say it is quiet. I get a lot of resonance in the large empty metal box. I guess I could stuff some foam in for sound dampening. I'll get some pics up soon and try for a vid. I'm beyond tight for space, so I think this is as far as I'm going to go with this bike.

I picked up a chopper bike on Friday for a good price and have been preoccupied with how to set that one up. I have a good idea in my head and have decided to swap the motor and batteries to it now that I have worked out the gearing. Quite a bit more room to play with in the frame so should be an easier set up from there. I also a have a bit of a trick for the drive set up, but I'll keep that under my hat till I see if it has possibilities. Won't be long. :lol:

FM

 

[flyinmonkie]

Here are the pics I promised. I did a long test ride tonight, and I'm slightly unimpressed with the performance. Could be the 600w motor or the SLA's not giving enough umph. Anyway, It ran well thought loud. Acceleration was better, but nothing to get excited about at all. It topped out at 30K/hr no matter what gear I was in so I am thinking that is all I'll get out of the motor and battery combo. I never drew more 30 amps the whole time and have been expecting to draw up to 40 as that is what the controller can handle. Anyway, I'm going to tear it all down and move everything to the chopper bike where there is more room to set everything up. So anyway, onto the pics. I'll start another thread for the chopper bike when I start it. I've taken this bike as far as I want.

 

[etard]

Before you completely give up on that bike and tear it apart maybe you should look into some cheap Lipo rc batteries, or get the Bosch 36 volt tool batteries (thats what I am getting). You are gonna need better batteries for the chopper anyway, might as well test them on this bike to see if you can't get some decent speed and acceleration. I can't wait to see what you comeup with for your chopper, that diamond plate will look more at home there.

 

[flyinmonkie]

Cheers etard,

Thanks for that. Yeah the chopper should be pretty sweet and look like everything is supposed to be there. Well, cheap and lipo's don't fit in the same sentence here in NZ, or I would have used them to start with. I'm not sure if it is the batteries or the wiring that is limiting the current to my motor. I have a rather long run to the ammeter and the wire might be a bit thin for than run. I may wire up the chopper with out the ammeter or wire it closer tot he batteries to try it out first.

I'm going to tear apart my current bike tonight. My mind is made up. It isn't really the lack of top speed that has inspired the change of bikes, it's the lack of space. To get the gear reduction down to what I need, I need more room than I have on the current bike. It'll make a good single speed commuter, or ebike number 3 with lipo's and a different drive set up.

So it's full speed ahead on the chopper this weekend. I'll start a new thread on it next week and will know if the first hurdle, the biggest, is jumpable. Tune in to to check it out.

 

[bzhwindtalker]

your aluminum box look realy nice (i whish my bike to be as clean) :lol:
how mutch does your caseing weigth?

 

[flyinmonkie]

Thanks, it looks better from a distance. The next one will be far better. I don't know how much it weighs as I've never weighed it. It isn't very heavy when the batteries are not in it. It also wasn't totally closed in. But was nice.