why I love friction drive

While taking my newly renovated bike trailer for a test run, I found that the spokes on my 24" coaster rear wheel were broken or loose. I decided after some research to replace it with a geared 24" rear wheel. I spent a couple of hours. Mounting it, setting the chain to the highest possible gear. the rigging a brake bracket because the bike's mounting area is used by the bumble bee mount. I rode the bike just now. Except for the one extra control it seems to work the same as before.

Always something to do with this bike, but it is never really very hard to do.
 
so a couple of days ago I noticed the junky wheel I had on my new build had spoke falling out then I noticed none ot them were tight. So I switched it for a five speed wheel I had. Today I was riding it down the road and the free wheel stopped doing it's thing, and the pedals began trying to beat me to death. I'm running out of junky wheels. I had to go up to a 26" wheel which is a little tall for me. I can manage but it isn't my favorite size.
 
It's raining today but it didn't start until after I made a quick test ride. I got the tire on the 26" wheel changed and the gears set a little lower then took off. The bike is great even with the big wheel. It is a one speed since I took the derailleur off but it is the right one speed. It catches the pedal just as the bike slow down on the hill. I can pedal then to keep it up to speed or wait until it is really slow and just hit the pedals a few times to make it up the hills so far.

Sense i couldn't ride I made a harp for the motor. I put two L shelf supports together to make an upside down U type things. One side i bolted to the motor frame. with the U over the tire I put a spring on the other side to make my tension for the roller on the wheel. Since the roller is directly attached to the motor the tension on the off side keeps the motor level, more or less. On the motor side I still have the scissor hinge that I pull with a cable to left the roller off the wheel to make a clutch of sorts. It should be a nice addition and also take some of the weight off the drive shaft.
 
Hey Deacon, I have used modified holesaw blades on my angle head weedeater driven build. DSC_1352.JPG
First I grind off the teeth. then saw off thr top, just below the setscrew hole. Then I chuck it in the lathe and face up the cut and drill it to my spindle size. They have a weld seam and two slots that help with traction.
 
Thats a heck of an idea... Im working on a handle bar drive now. I can turn an axle bolt backward and it will center the the hole for a but to go to the motor. but it isn't quite as large in diameter as I would like so I sliced a larger diameter tube tonight and drove the handlebar into it. I'm not sure what the diameter is or how it will work but I plan to test it and if it works okay,. I'm going to weld it where I slicked the larger tube. Not sure that made much sense but it looks pretty cool right now.
 
I took the bike with all the recent changes to the mall today. I was one of the big tests and it passed with flying colors. It is controlable and it will climb a nasty hill with only minor pedal help. I expect that it would climb it without the help but at a speed that would make the traffic behind me tear their hair. I have to be in the left lane of a two lane each direction road. I have to be in that lane to make a left turn at the top of the hill. Still it did it climb just fine. I think it has a little less toque than the ebike but not so much that it isn't a good ride.
 
In the spirit of not being very smart to build friction drive,. I have been using my new bike with only a front brake. I am running a mountain bike wheel on the back and had no place to hook the break caliper after I used the cross brace to hold the motor. So for several days now I have been riding with just a front brake and it is quite adequate to stop the bike. But I always do the "what if" thing until I am sick of it myself.

To make a long story as short as possible, I figured a way to mount the caliper on the seat down tube holder. Just a strong L bracket and a pipe band type clamp and its working just fine. Looks a little strange and i haven't actually ridden it yet but it looks like it's going to work fine.
 
At the risk of boring heck out of everyone, I would like to mention that I took the Ebike out today. I managed to get the battery packs straight, so I took it to the mall about two miles round trip. I have made that trip several time with the ebike and then several with the gasoline bike, so today I got to compare them one pretty much after the other since I rode the gas bike yesterday.

We have pretty much decided that the gas bike is about 35 to 40 cc. It is running the same size roller as the kits have I think. Just over and inch and knurled a little. The ebike is about 900 watts at 36v. I pulled 6 12 ah batteries in the trailer today.

The bikes pull very much the same with a slight edge going to the ebike for torque. If I were going to the shopping center or the mall for a food or cola run, I would opt for the ebike. No gas to buy and it would pull the hills just a little better. Not a lot mind you just a little better. With the trailer and a double stack milk carton, I can get a pretty good amount of groceries in it.\

If I'm just going out to fool around, I think I like the gasoline bike better. I don't have to take a trailer so it is lighter. I can refuel it if necessary, even though on a full tank I can probably go about the same range as the ebike on a full charge with its heavy batteries. It would take several hours to refill the batteries but only a couple of minutes to refill the gasoline tank. So I found it interesting. If there were some way to do it I would like to build the original plan a mix of gas friction on the rear and electric friction on the front. It is just too much juggling but it can be done.
 
I got myself a Tecumseh 3.5 hp motor from a snow thrower yesterday. I spend the day working on taking stuff off it. It came with a centrifugal clutch I didn't want so I pulled it. I never could figure out how to get the nut off the drive shaft since it had a hole in the center of it. I drilled and tapped it. then I bolted a piece of pipe on it. Now I'm going to see what it will do once I get the mount finished. It's a heavy mother to be hanging on the side of my bike. I hope I can keep it together. It might just pull me down.
 
I was getting the test bike ready to test the engine, and found that i have butchered it too much to be useful as a test platform. I went to the thrift store to pick up another test bike and found that they have sold out all their bikes. I guess a warm weekend get people thinking bike.

I will just have to put this project off a week or so..
 
It looks like all the bike tests I made over the last couple of years paid off. I managed to get the 3.5 Tecumseh mounted without too much trouble. Not only that I rebuilt a used bike to put it on. I got a 15speed mountain bike at the junk store, then switched the 26" rear wheel for a 20" coaster brake wheel. I was surprised that it would work with only minor changes. I had to remove the chain guide and derailleur, but otherwise the coaster wheel seems to work fine.

For now I left the 26" front wheel in place because the front brakes work so well. I have no idea what the balance will be like when that big ole motor starts to spin. I am exhausted so I left the project almost finished. I need to rig the lift clutch, the spring tension and a throttle. I should probably do as much welding as I think will help before I put gas in so that I check to see if it will start. After all this work if it doesn't start I am going be one unhappy camper.
 
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I finished the new bike today. I have never run a motor this big on a bike. It is approx 80cc 3.5 hp. I am running it as a friction drive with a about an 1.5" drive wheel which is smooth. I'm not sure what to expect. If anybody run a big friction drive motor I would sure like to have an idea before I take off on it.
 
I believe that is the common thought yes. I have never seen the two head to head so I really can't say it is fact or not. Most of the complains I hear are about tire wear. But the power transfer is something I hear a lot of.

I do know that today I put the 80cc motor to my first riding test. I threw two drive wheels off and did not get a complete test but I did find one thing for real. If the motor is running, even at barely above idle, it will pull me forward. I was shocked the first time i had to move my feet to keep the bike from running away on me.

When i had the china kit the bike would choke, if I dropped the clutch while it was standing still. I had the big motor so I honestly can't say which is better. To me its all about the ease of building and upkeep. I threw chains through wheels and had all kinds of other problems. A friction drive is easy to build and simple to maintain.

And cheap. I paid forty bucks for this three hp motor and it runs great. Of course I still have to have someone else weld the drive on but my neighbor is going to do it tomorrow, The drive wheel is a bit of seat post from an old project. The throttle is the front gear shifter. So I can build a lot of these bikes for what a chain drive kit costs. I dont have to worry about sprocket being lined up chain slack any of that stuff.

Probably not a good answer to your question but it's all I really know for sure.

My clutch is a piece of brake cable or a couple of metal rods. Other than the motor that's about it. My more or less 40 cc does all the speed i want but it is weak on the hills, this new one is not going to be weak on the hills but I haven't been able to test it for speed yet. I doubt that it will be much better. I'm expecting it to only do about twenty mpg maybe 25 but I expect it to climb any hill faster than I can pedal.
 
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You can build this with very little skill. 3.5 hp direct friction drive and it hums also a little too big for the DMV but I'm not talking. It also wasn't very expensive. The motor was forty bucks and the drive wheel is a pipe nipple from the hardware store. Throttle was the gear shift lever. Since I switched out the rear wheel for a small coaster wheel I had the rear brake lever became the lift clutch control.
 
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Isnt it constantly going up hill with the big wheel in the front? LOL! Looks great, should be a real power house! I have a Honda OHV engine laying around, when I get through with the Lifan/Cranny, was thinking of an inframe friction drive. Would just turn the engine around backwards so the bike will go in the right direction, the add a belt driven roller with a spring idler for tension, auto clutch of course. Should be about as trouble free as a normal configuration with the advantage of the lower center of gravity.
 
It is truly weird riding for sure. I haven't been able to get much testing done today. Weather was so nice I cut the grass. The the recoil starter failed. Had to go for gas mama had the car and gone so I rode the ebike. Its still be best for traffic. Just turn throttle and there is power. I have to redo the clutch. That after supper.
 
Let me tell you what I think about friction drive. All of the engines I have tried seem to have about the same number of revolutions. So the speed on the flat is pretty much the same for all of them. The hills is where the difference is to be found. Yes even the 3.5 hp slows down on the hills but not any where near as much as the 40? cc bumble bee. The 3.5hp seems to have more testosterone than the smaller motors. It just feels tougher, though it probably isn't. I wanted to try it for the hill climbing ability but otherwise it is a lot of the same things. The smaller motor is adequate on the flats it's just the hills that it fall short. I can never pedal this bike, It is just that powerful. It also starts without the bike having to be pedaled though I do try to do that too.

I made a couple of rookie mistakes but all's well that ends well, I suppose. I have two bikes with that lift clutch and I know now for a fact you want to use a men's model bike. The sissy bike isn't set up for it as well. Also don't waste your time with cables get fence stretcher bars to use for linkage.
 
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