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deacon · #1 (**permalink**) 07-30-2009, 07:01 AM

Who would have thunk it. When I built my very first power bike it was an Ebike. I had my neighbor weld a drive onto a scooter motor and hooked it to the rear of an old huffy. It wasn't fast and the range wasn't much but it worked. Then I got caught up in a BETTER idea.

Yesterday, I decided that since I have learned so much I wanted to do it again. Just as simple as before but with an improved knowledge (I hope) of what works best. I have one pusher bike that runs really well. I need to retest it, since I over powered the controller, to make sure it still works.

Then I am going to build a direct friction drive. Pushers and gasoline motors are complicated. A friction drive is simple and I think I want to simplify things this time. I am still looking for that bike to ride to the store for a loaf of bread and a jar of peanut butter.

deacon · #2 (**permalink**) 07-31-2009, 03:54 PM

I got the motor onto a bike frame I had but I lost the front brakes. I had to mount it on the front. I got to ride it this afternoon and it looks to be fast for an ebike. I don't have decent brakes so i only rode it up and down the drive. I am going to take it off the 26" bike and put it on a 20" one. That is after a trip to the thrift store to buy it. The mountain bike I have just won't do. I will probably go with a kids bike so I can mount the drive over the rear wheel.

Since this uses a scooter wheel to turn the bike wheel, it will run on a knobby tire but I'm hoping I can find a not so knobby one laying about.

deacon · #3 (**permalink**) 08-01-2009, 02:20 PM

strange looking beast.

I had a blowout on my first ride. I got about 3/4 miles down the test track and it went pop. Scared me a bit.

deacon · #4 (**permalink**) 08-01-2009, 03:44 PM

I should be able to compare my last two bikes since I used exactly the same motor on both. However I can't. Here is why. When I used the stock scooter wheel and sprocket as a pusher wheel the results were close to those of the this friction drive with the stock scooter wheel and sprocket. I find that it has a lot to do with modifications and I haven't started to modify this friction drive yet.

The pusher mods were, a smaller sprocket welded to a 16" bike coaster wheel. That was the most efficient performance wise. I pretty much cut the size of the sprocket in half, then added 25% more wheel radius.

Looks like I need to do something like that to the friction drive. It is going to be hard since the wheel is pretty much max now. I think I will look around to see what I can find to be modified.

deacon · #5 (**permalink**) 08-03-2009, 10:18 AM

I got the bike set up better thank before. It still has a stock motor and a stock scooter wheel set up as a friction drive and it works pretty well now. About like an average ride. top speed is about ten miles an hour I would guess. Minimum equipment. I have no controller but the power consumption seems about the same as with one.

I have a larger sprocket on the way. I was going to make a new drive wheel with it but I might just put it on the motor and use it that way. I haven't made a final decision yet. I might just experiment.

deacon · #6 (**permalink**) 08-03-2009, 12:17 PM

I took the bike and trailer out on a real world ride to the park. It worked very well. It is slow but that's okay. I'm not really out in traffic with it on that run. I'm toying with the idea of making a friction drive from the fast pusher I have.

I'll be giving that some thought while I wait for the sprocket, which I will use on the home made drive wheel. That is if I go that route.

The evaluation of the 350 watt motor with no controller on a friction drive using the rear scooter wheel as a drive is that it has lots of torgue. It is slow but it climbs small hills at almost the same speed as it runs on the flat. It probably is doing 10 to 12 mph which is better than I could do on a pedal bike. It will also help me start from a dead stop without blowing a fuse. It does have some good points.

The worst thing is that I put it one a bike with no suspension at all. It is one rough riding sob for sure. The twenty inch sissy frame is really too light weight I think and the pedal gear ration is all very low gear.It probably could use a larger front chain ring. I might take a look at that. I'm pretty sure I have one laying about.

deacon · #7 (**permalink**) 08-04-2009, 07:18 PM

I rode the friction drive to the park today. I built it primarily for that purpose. An easy to ride inexpensive more or less disposable bike. It is low powered and slow compared to my 500 watt pusher bike, but it is a pleasant ride. The bike does not require that I maintain a high speed at all. As a matter of fact it will just skip over the wheel when I start or when if I get too slow going uphill. I can pedal at a very moderate rate to prevent it skipping. So yes I am slow but I don't mind at all. By the way this bike has great torque. It also has better range just because it is so slow that it will coast for a long way before I have to kick the power back on when it is going on the flat.

I have started to build my own drive wheel. If I am successful, I might just put it on the fast pusher so that I don't have to mess up this one. What in effect I am building is a mini pusher that ride on top of the bikes wheel. It is a little different but not much. The one I have now is no different at all. By the what

motorbiker · #8 (**permalink**) 08-05-2009, 02:13 AM

Hi, friction drive trips me out. If the bicycle tire is made smaller and the roller stays the same the bicycle tire will turn faster but the bike will go the same speed because the smaller tire has to spin faster to make the bike go the same speed as the larger size tire ? Right ?

How many teeth are on the sprockets and what are the real time tire sizes ?

What size roller would need to be on the motor shaft if the roller on the motor shaft was right on the tire ?

With my weed wacker 33cc motor it needs to be about 7/8" diameter for me. Thanks

deacon · #9 (**permalink**) 08-05-2009, 07:11 AM

Bike tire size is immaterial. If you turn the tire one inch the bike moves one inch no matter what size the tire on the bike. Its all about the drive wheel and the motor. I usually use a direct drive on my friction setup but not this time. This time I am using the scooter motor as it was on the scooter. I just moved the whole setup to the top of the bike wheel.

This one has an 11tooth sprocket on the motor. Then it has a 44tooth sprocket on a 8 inch scooter wheel. It will push the bike along faster than I could pedal it uphill. What it really does is to make it possible for me to climb a moderate sized incline as if I was pedaling on a flat.

The pusher motor does better because it is a bigger drive wheel and a stronger motor. This set up is the smallest thing I have at the moment.

I am currently trying to assemble a DIY drive wheel. It is a six inch lawn mower wheel on a 3/8" axle. It will have an 18 tooth sprocket in the drive and an 11tooth sprocket on the motor. It will turn the wheel faster but the wheel has a smaller diameter. It should change the overall speed of the bike, but it most likely will reduce the torque. For that reason I have to try it before I get married to it. I love the torque of the bike the way it is now.

deacon · #10 (**permalink**) 08-06-2009, 06:10 PM

On the diy drive wheel setup. My bearings came. I had to mount them to the drive wheel frame since I couldn't mount them to the wheel. Unlike a bike the axle is going to turn along with the wheel.

Holding the bearing against the frame is the trick it seems. I drilled a hole in the frame just a little larger then the 1/2 inch inside ring of the bearing. The bearing bore is 3/8 so I am using a 3/8 all thread rod as an axle.

I have attached a lawn mower 6" wheel to the axle with nuts and lock washers. I have an 18 tooth 1 5/8" sprocket coming. I will attach it with nuts and lock washers as well. If that won't hold then I'll just weld it.

I drilled out a couple of 5/16 nuts and ground off the corners to make spacers for the inside of the bearings. I drilled a hole in a piece of wood I had which is the same size as the bearing thickness. I used a 5/8 cut washer at the rear of the bearing a keep it from moving. A standard 3/8 nut will turn inside the washer so it is a good fit.

I think this thing will work but I don't know for sure. I'll let you know in the next day or so.

If this one works out okay I might just build another one for my smaller bike. I like the engine on it which is also friction now. I am scraping out all my pusher motors. They were fun and worked very well but it's time to try something new. The friction drives are the something new, even though I have worked with them before. I have not worked with them this way. Before I used direct drives attached to the motor.