Friction Drive Encounters Oil

Nehmo · Apr 1, 2013

Water is bad enough for a friction drive. In my case, the engine revs up every time I cross a wet spot (not a puddle, just a wet spot). But an even worse problem is oil on the pavement. I'm working ways to deal with it. I suppose just washing the tire & roller in detergent?
In the end, if oily pavement is unavoidable, a FD isn't practical.

Norman · Apr 2, 2013

I wonder if adding a sand hopper over the drive wheel would help? Sort of like the railroad engines use? encounter a wet spot( that sounds sort of nasty don't it) hit the sand hopper lever.
I'm just B..S..ing ya.

Nehmo · Apr 2, 2013

Norman said:
I wonder if adding a sand hopper over the drive wheel would help? Sort of like the railroad engines use? encounter a wet spot( that sounds sort of nasty don't it) hit the sand hopper lever.
I'm just B..S..ing ya.

I, personally, was thinking more along the lines of a laser incineration beam aimed on the pavement directly in front of the tire.
You would need, at least at this point, manual triggering of the beam. And, of course, the beam should be amiable in any forward direction (for defensive purposes).

2door · Apr 2, 2013

Thermo-nuclear heat would work better than a laser. You'd get a broader area of clean pavement.

Seriously, how much force are you using to set the roller to the tire? They need to be snug. Don't worry about compressing the tire a little. It won't hurt anything.

Tom

Nehmo · Apr 3, 2013

2door said:
Thermo-nuclear heat would work better than a laser. You'd get a broader area of clean pavement.

Seriously, how much force are you using to set the roller to the tire? They need to be snug. Don't worry about compressing the tire a little. It won't hurt anything.

My friction drive is a wooden roller 3.5" diameter pressed to the tire by the weight of the 79cc engine.

But since I began writing this post, I moved my gas tank to the front of the bike. The pic above is it. (It's a shot at a distance & cropped.)
This will reduce the weight even more, but I'm thinking on using a spring arrangement rather than what I have.

wheelbender6 · Apr 3, 2013

You could keep some rubbing alcohol and a clean rag in your tool kit to degrease the tire and roller. I don't know if cutting some shallow cross grooves in the wooden roller with a dremel or rasp may help.
I have found the pavement where the big trucks wait for traffic lights to stay pretty oily.

2door · Apr 3, 2013

Nehmo said:
My friction drive is a wooden roller 3.5" diameter pressed to the tire by the weight of the 79cc engine.

But since I began writing this post, I moved my gas tank to the front of the bike. The pic above is it. (It's a shot at a distance & cropped.)
This will reduce the weight even more, but I'm thinking on using a spring arrangement rather than what I have.

I believe you're going to have to apply more weight/force to the tire than you are doing.
Engine weight alone won't do it. We did some experimentation and came up with somewhere between 30 to 40 lbs to provide enough friction for wet streets. Do you have a way to adjust the roller position relative to the tire?
Also are your tires smooth or knobby?

Tom

Nehmo · Apr 3, 2013

2door said:
I believe you're going to have to apply more weight/force to the tire than you are doing.
Engine weight alone won't do it. We did some experimentation and came up with somewhere between 30 to 40 lbs to provide enough friction for wet streets. Do you have a way to adjust the roller position relative to the tire?
Also are your tires smooth or knobby?

Tom

I can't easily change the position of the roller.
I'm using 29" tires, which are difficult to get cheap. I use the knobby ones that WalMart retails.
This pic is before I moved the gas tank

I believe a partial solution is to use a larger roller (and gear down to compensate).
And another improvement would be to use spring tension to press the roller against the tire. I'm considering a clutch (my clutch consists of lifting and lowering the roller & engine) that's stable in either completely engaged or completely disengaged. I could toggle from one to the other. I really don't use the gradual engagement that is used in a conventional car.
Finally, I must concede a friction drive is simply inferior to a chain or belt.

Velodrome · Apr 4, 2013

How many miles on your roller? Is it worn smooth ?

andrewflores17 · Apr 4, 2013

friction drive has one universal thing going for it simplicity i dont own one nor plan to but the less things that are involved is always a plus .

what about lead weights or even the guts of a battery (dont get a acid burn) if you cant add a spring you can add weight and lead weighs the most idk just spitballing ideas here . cvlt1

Nehmo · Apr 4, 2013

wheelbender6 said:
You could keep some rubbing alcohol and a clean rag in your tool kit to degrease the tire and roller. ....

Does alcohol clean grease? I was going to try motor ether
(also called starting fluid). I'll report back on this one.

It seems once the roller & tire get coated with a layer of oil, it's really hard to remove it. I need something I can carry and use without major trouble.

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Friction Drive Encounters Oil

Nehmo

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