I saw this concept all wheel drive Motorcycle and was wondering if anyone has done this for a bicycle? if it can even be done. I know it wouldnt really be practical or serve a purpose but I think it would be cool
Has anyone tried this? Can it be done? PIC
- Thread starter skillsthebarber
- Start date
Help Support Rat Rod Bikes Bicycle Forum:
My guess it drives the front wheel though a CV joint (the sprocket is hooked to a small drive axle, not the wheel itself) and utilizes in-hub steering of some sort. The main drawback I can see is that the chain would have to be positioned way to the outside of the bike for tire clearance when turning. A more useful (though still mechanically inefficient) drive system might be to replicate the 2wd Rokon Trainbreaker... maybe on a fat-tired mountainbike with really low gears for use in sand/snow.
There was a cable-driven attempt at a 2wd MTB is the '80s or '90s, IIRC.
There was a cable-driven attempt at a 2wd MTB is the '80s or '90s, IIRC.
I think it could be done. Not much advantage though on a bicycle.
If I had to build a two-wheel bicycle, I think I would get a pair of small hydro pumps and use one as a motor to drive the front wheel off the rear. You could hook up the lines with bypass valves to allow the front to freewheel faster than the rear, but that would prevent the front from ever turning slower than the rear.
That was named the "Legacy 2WD" bike(s). I never owned one, but test-rode one at a LBS in some mud puddles in the rear parking lot.
It had three problems that I recall:
1) it definitely worked, but you had to be in such slippery conditions that the rear tire's traction alone couldn't keep you moving forward. You could c-r-a-w-l through deep mud puddles, and as long as you kept pedaling, you never got stuck.
2) there were durability concerns. The plastic gears were exposed and the drive "shaft" was a weedwacker-style cord (maybe thicker than a weedwacker, but the same idea). THose types of cables aren't capable of withstanding a lot of torque, but that's how they were used here.
3) the bikes themselves weren't very good. Legacy had to charge $400 for a MTB that (without the 2WD setup) would have cost <$200 at Wal-Mart.
If I had to build a two-wheel bicycle, I think I would get a pair of small hydro pumps and use one as a motor to drive the front wheel off the rear. You could hook up the lines with bypass valves to allow the front to freewheel faster than the rear, but that would prevent the front from ever turning slower than the rear.
gowjobs said:
That was named the "Legacy 2WD" bike(s). I never owned one, but test-rode one at a LBS in some mud puddles in the rear parking lot.
It had three problems that I recall:
1) it definitely worked, but you had to be in such slippery conditions that the rear tire's traction alone couldn't keep you moving forward. You could c-r-a-w-l through deep mud puddles, and as long as you kept pedaling, you never got stuck.
2) there were durability concerns. The plastic gears were exposed and the drive "shaft" was a weedwacker-style cord (maybe thicker than a weedwacker, but the same idea). THose types of cables aren't capable of withstanding a lot of torque, but that's how they were used here.
3) the bikes themselves weren't very good. Legacy had to charge $400 for a MTB that (without the 2WD setup) would have cost <$200 at Wal-Mart.
I thought you might like to see some photos of a bike I first in the early 80's. I dug the parts out of storage late last year and put it back together. It now has a new seat and pedals. I couldn't find the original back wheel I had used. The bike is rideable in front wheel drive and two wheel drive with a longer chain run to the back wheel. It is about 20 pounds heavier than it was. I built this bike just to see if it would work, and it does.
One of my test pilots (youngest daughter)
thats freakin cool!! :shock:
that is one cool machine. It got me wondering, could you run a double sprocket like this with the inside sprocket running a chain to the rear and the outside sprocket running a chain to the top/front
Yes that would work. I had originally just ran a long chain from the rear wheel up around the top sprocket and down under the crank sprocket and back to the rear wheel. It clears the frame. If I can find the chain I'll put it back on and take more pictures.skillsthebarber said:that is one cool machine. It got me wondering, could you run a double sprocket like this with the inside sprocket running a chain to the rear and the outside sprocket running a chain to the top/front
gowjobs said:
Here's the newer version from Christini, seem to have it down a lot better now using metal bevel gears, better pics of the drive here
http://www.christinibicycles.com/tech-about.php
A guy in North Dakota made an all wheel drive bike using a cable to drive a worm gear on the front wheel.
Here's one example of a nearly-suitable hydraulic motor-
http://www.surpluscenter.com/item.asp?i ... =hydraulic
It's 2+ inches diameter and 4.5 inches long. 6 lbs each, but could be lighter if made from aluminum and pared down (all the parts made thinner overall) since it's way overbuilt for this use.
This is fairly-easy since the only power connection is rubber hydraulic lines, which you can run anywhere and bend as you need to without losing much power.
-----
Another way I have heard of is to drive an electric motor off the back wheel, as a generator to drive another electric motor on the front wheel.
This is probably the easiest way to do it of all,,,,,, but it's expensive ($300+ per hub-motor) and the one person I know of who tried it said that the motor/generator didn't make much electricity at very low speeds, which was exactly when you'd want the 2WD effect to work.
It might be possible to rewind the "generator" to work better for this, but I dunno how those things are built inside..... ? I haven't ever played with e-bikes at all.
http://www.surpluscenter.com/item.asp?i ... =hydraulic
It's 2+ inches diameter and 4.5 inches long. 6 lbs each, but could be lighter if made from aluminum and pared down (all the parts made thinner overall) since it's way overbuilt for this use.
This is fairly-easy since the only power connection is rubber hydraulic lines, which you can run anywhere and bend as you need to without losing much power.
-----
Another way I have heard of is to drive an electric motor off the back wheel, as a generator to drive another electric motor on the front wheel.
This is probably the easiest way to do it of all,,,,,, but it's expensive ($300+ per hub-motor) and the one person I know of who tried it said that the motor/generator didn't make much electricity at very low speeds, which was exactly when you'd want the 2WD effect to work.
It might be possible to rewind the "generator" to work better for this, but I dunno how those things are built inside..... ? I haven't ever played with e-bikes at all.
Yea but not all the time. Only when the front-wheel-drive is the only thing that's keeping you going.JoKeR63 said:
Losing 25% of your power sounds bad, but if you can still get through some deep mud or up a muddy hill that you otherwise wouldn't have, it would still be a neat thing to have.
When you were rolling on regular ground I doubt if it would add much effort at all (other than the weight) since the motor and the generator would both be spinning at the same RPM anyway. The front motor wouldn't be any load on the rear-generator.
It would still be heavy and expensive tho'.
I like the hydraulics idea much better.
DougC said:
Although the numbers are are debatable (eddy currents, that sort of thing), I agree that hydralics are better.
I wanted to use hydralics for a power assist recumbent idea I've been kicking around for years. I just haven't seen the product availability I need yet. And it ain't gonna' be cheap!
