2.4 HP Friction Drive
- Thread starter CoconutFriction
- Start date
levsmith
Member
looks good
looks nice. do you have any pictures of the friction part?
looks nice. do you have any pictures of the friction part?
S
SirJakesus
Guest
That thing looks darn cool! Are you sure you're only pulling 2.4hp with an 81cc? I get 2.2 from my 43cc. Just sounds low is all. Nice ride.
s_beaudry
Member
Very nice ride....
That has to be the biggest friction drive engine I have seen on this site!
That has to be the biggest friction drive engine I have seen on this site!
L
Large Filipino
Guest
That friction wheel looks like a rim with the tire taken out.
That's awesome for you have more rolling surface that should equal less tire wear.
What's up with all that down there?
We need more pics dude!
What's this sprocket?
And man if that doesn't look like a B&S 3.5 hp engine.
And you plated it!
Bravo!!
That's awesome for you have more rolling surface that should equal less tire wear.
What's up with all that down there?
We need more pics dude!
What's this sprocket?
And man if that doesn't look like a B&S 3.5 hp engine.
And you plated it!
Bravo!!
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Happy Valley
Active Member
Large Filipino;150393 What's up with all that down there? We need more pics dude! What's this sprocket? [/QUOTE said:
CoconutFriction
New Member
I'll post some more pictures soon, dealing with the whole hurricane/tropical storm fay thing today, that'll keep the ride in the garage for a few days. I have a centrifugal clutch chain driving a sprocket I welded on to a trailer tire rim. There's so much stuff down there, because I tried several different ways to make this work. I first tried a chain driven system, but had so much problems with the chain hopping off and mounting the sprocket to the spokes, etc, I got rid of that. So there was a lot of welding and cutting going on until I found a system that works, and this set up works awesome. The engine does look big, but the specs list it as a 2.4/81cc
Mountainman
Active Member
Nice looking MB - yes - I am still new - that engine looks big !! My little Subaru 35cc seems to be a lot smaller - would like some of that power you are talking about - but for now - staying under the Ca 2.0 hp law - legal issue.. Happy Riding from - Mountainman
CoconutFriction
New Member
More Pics, New Rack System, Check it out!
I've been working on a rack system that fits any bike and is adjustable in all directions. The same rack with the friction drive system will be for an electric drive, 49cc or 81cc 4 cycle. The 81cc is mounted on it and works awesome. A couple hundred flawless miles so far. Any yes, it's a 2.4 hp 81cc engine on the bike.
I've been working on a rack system that fits any bike and is adjustable in all directions. The same rack with the friction drive system will be for an electric drive, 49cc or 81cc 4 cycle. The 81cc is mounted on it and works awesome. A couple hundred flawless miles so far. Any yes, it's a 2.4 hp 81cc engine on the bike.
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loquin
Well-Known Member
The only thing I would be concerned about is the concave roller. Yes, it gives you more surface contact with the tire. But, since the diameter of the rim is greater than the diameter of the center of the face, the linear speed (the speed which the roller is trying to push the bike) of the rim is correspondingly higher than the linear speed of the center of the face.
In one revolution of the roller, the rim, with its larger diameter, moves farther than the center of the roller. But, the rubber of the tire cannot move farther on it's edge than at the center of the tire face. So, you have relative motion, and increased friction, resulting in more tire wear than if you use a flat faced roller.
With a flat faced roller, the tire, being flexible, can conform to this shape, so you will not experience the surface wear you will get with a concave roller.
Ref the attached diagram.
Lets assume that you have a 5 inch larger diameter (D1), and a 4 inch smaller diameter (D2), with 1500 RPM rotational velocity. The rim speeds of the two circles would be:
D1 = 1500 * 5 * 3.14 * 60 / (12 * 5280) = 22.3 MPH
D2 = 1500 * 4 * 3.14 * 60 / (12 * 5280) = 17.8 MPH
So, the crown of the tire is being pushed almost 5 miles per hour faster than the 'corner' of the tire. That is a situation which will lead to poor tire wear, and increased opportunity for tire blowouts on long runs
There's a reason why all the friction drive makers run with 'flat' rollers, and it's not because it's easier to make. (although, coincidently, that IS a plus...)
In one revolution of the roller, the rim, with its larger diameter, moves farther than the center of the roller. But, the rubber of the tire cannot move farther on it's edge than at the center of the tire face. So, you have relative motion, and increased friction, resulting in more tire wear than if you use a flat faced roller.
With a flat faced roller, the tire, being flexible, can conform to this shape, so you will not experience the surface wear you will get with a concave roller.
Ref the attached diagram.
Lets assume that you have a 5 inch larger diameter (D1), and a 4 inch smaller diameter (D2), with 1500 RPM rotational velocity. The rim speeds of the two circles would be:
D1 = 1500 * 5 * 3.14 * 60 / (12 * 5280) = 22.3 MPH
D2 = 1500 * 4 * 3.14 * 60 / (12 * 5280) = 17.8 MPH
So, the crown of the tire is being pushed almost 5 miles per hour faster than the 'corner' of the tire. That is a situation which will lead to poor tire wear, and increased opportunity for tire blowouts on long runs
There's a reason why all the friction drive makers run with 'flat' rollers, and it's not because it's easier to make. (although, coincidently, that IS a plus...)
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