have question about engine

[beastmode986]

well i can get a lawn mower 3.5 hp for 20$ and im wondering if i bought a used cheap bike and mounted the engine so the vertical shaft was rubbing against the side of the tire would this configuration work? i havent seen a friction drive using a vert shaft before so i was just wonder and is the engine to weak????

 

[CAPTAINCAVEMAN]

interesting idea but I think you will have a lot of trouble with slipping but I have never seen anything like that

 

[rcarteraz07]

I don't see how this would work. If you do manage to make it work post a video please. Best of luck!

 

[Jake.B]

I thought about this before. Side walls
Of tires are the weekest point with no grip. It would slip and wear tremendously. I wouldent try it unless it can be done cheap.

 

[landuse]

I have read about this idea over at www.motoredbikes.com, and everyone who has tried it has failed. Loke Jake.B says, the sides are the weekens point, and you cant get a good grip

Give it try though, you might figure it out

 

[kmy]

Make an adapter/drive system that drive BOTH sides of the tire. It might work. Some cheap gears from Hardware store might do it.

 

[Doc Sprocket]

You can give it a go, and I do wish you good luck- but I can't see it being worth the effort. Not enough grip on the sidewall, and too much scrub.

 

[beastmode986]

just had an idea what if i extend the shaft a bit and put a sprocket or gear or something that will catch the spokes and make the wheels rotate that way?

 

[sexyvicta]

you would just rip the spokes off lol

 

[landuse]

you would just rip the spokes off lol

X 2. Would be a waste of a good wheel

 

[OzFab]

Did you forget about the bit in between the tyre & the spokes? If you put a rubber pulley on the shaft to contact the rim it may work.

I'm surprised no one has picked up on the fact that a 3.5 B&S would weigh more than most bicycles & having it mounted above the wheel would create sever imbalance issues

 

[jman231994]

The main problem with side mounting a friction drive system is that the diameter of the wheel is not consistent over the length of the roller, ie at the end closest to the engine it might be 20" but at the other end of the roller its 18", so even if you get enough friction between them for it to work you will still tear up tyres

 

[fowler]

Also bike bearing have no ability to take side load

So if u get enough grip u will just pop the bearing in no time

 

[jman231994]

Unless you have a free spinning roller on the other side of the wheel to balance the force.

 

[Doc Sprocket]

...Which may be true, but still does not address the horrible sidewall scrubbing that you were describing. Furthermore, if the opposing roller is applying enough force to properly counteract the drive roller's sideload, that will add yet more friction and drag.

 

[r_chez_08]

Did you forget about the bit in between the tyre & the spokes? If you put a rubber pulley on the shaft to contact the rim it may work

I think this would be the best idea, especially if you could mount a free running pulley on the other side to clamp the wheel in the middle. I dunno where you could get the little wheels from though.
Edit:
http://www.mcmaster.com/#rubber-wheels/=hpq9y0

 

[Doc Sprocket]

My only concern about an arrangement like that is friction vs slip. To get the rubber wheel to get a good grab on that rim, the rim must remain clean and dry. I would think a fair bit of pressure would need to be applied in order to achieve a decent grip. That's where you'd get some friction losses.

On the other hand, this IS a friction drive right? Give it a go! I'd like to see a proof-of-concept build here. By putting the engine on a pivot that can swivel in and out, you could accomplish clutching.

 

[r_chez_08]

You could have a few trampoline springs to tension the motor, then get the motor to be pulled by a brake lever with one or multiple pivots to 'gear it down' so the rubber wheel has a tiny gap of a few mm when the lever is pulled.
That could work quite well. After all brkae pads work on the same surface, right?