Build of 3 Speed Friction Drive

[Poupoudoum]

If you ever come to bordeaux, I will give you a bottle
Here the weather is great, it's sunny and warm (17 degrees C), perfect time to ride!

 

[Ludwig II]

What engine are you using? Ancient or modern? Mobylette or Immobilette?

 

[Poupoudoum]

Mostly chainsaws, it's easy to find, it's strong an reliable, and it's powerfull.

Here is my website:
http://ciclotron.forever.free.fr/pages.php?menu=28&i=chainsaw-bike-mini-chopper-bobber-homemade

 

[rawly old]

Don't know about Britain or Bordeaux, But I'm considering building an ark here.
I live in a rain forest, but this year it is truly absurd. I'm working on a way to
put pontoons on the bike.

 

[happycheapskate]

That's really cool. I was attracted to this thread for the idea of a 3 speed friction drive. I have thought of sometime trying to convert a Dax Friction Drive to a 3 speed, by bolting on struts to contain the 3 speed hub (used as roller also), and using a chain drive between the original driveshaft and the hub. I'm trying to find the thread where someone said it was done before, by shaving off the flanges on a SA 3 speed, and adding various traction material (bonded rubber/urethane or grit).

Are you still using the bike with the wooden rollers and skate wheel?

 

[Lee_K]

I got the bike done to the point where I could take a few short test rides last fall, and it worked well. It has been in my basement all winter and I still have more work before I take it out for some long rides. I am currently working on a fiberglass gas tank to fit available space.

The wooden driven pulleys have flat OD's, I have a similar wood pulley on my other bike with 1000 miles and no wear. The engine pulley has grooves and is aluminum, the other drive pulley is wood with grooves, I will have to see how that holds up.

If you try something like this, think about engine rotation direction. The S/A input has to be on the left side and I wanted to center the engine so I needed the jackshaft to get the correct rotation direction for left side input to the hub. Some 2 cycle engines rotate CW and would not need the jackshaft.

After I get some miles on it I will take the hub apart and post my opinion about it's capability for this job. I expect there might be a wear problem on the 4 pins that the planet gears ride on. The gears should be plenty strong enough, but it will be running at much high speeds than originally intended.

This is progressing slowly, but this summer I will have test results.

 

[happycheapskate]

Yes, the hub would be running at much higher speeds, so that could be a problem. I guess it depends on how much you use the bike if it will be a serious issue or just the inconvenience of replacing the hub later when it slips or wear is detectable. I'm guessing you could get a couple years of frequent use out of one, if the parts inside are steel, and you adjust the bearing cones when necessary. If you use the best high-temp grease like Lucas or something, it should do ok, and maybe it's possible (for someone with wood tools) to add a wooden wheel to the hub similar to your skateboard wheel. That should knock down wear some, and take care of the traction issue (untreated hub shell as roller would be slick).

I planned on using a threaded freewheel adapter and BMX freewheel to go from the dax driveshaft to the 3 speed hub.

On the other hand, if law allows, you could just get a stronger engine and go with the 1.5 roller.

 

[Lee_K]

If you try this, keep in mind that the middle gear just locks up the hub and it all rotates together, so no wear on internal components. The high and low gears use the internal gears to speed up or slow down the output. So if you select the drive ratios and roller diameter so most of your riding is in the middle gear, then this could last a long time.