Motorized Bikes

EvilDustBooger · Post by **EvilDustBooger** » Fri Apr 25, 2008 2:35 pm

I would like to know if anyone has had any experience with motorizing a Bicycle.
I am interested in installing a 50 to 80cc 2-stroke version on a hybrid mountain bike.
Not really for the playa, but as a cost / gas saving device for short trips around town.
I understand you can get 150 - 200 MPG with some models
I`d appreciate any info about recommended models, benefits, dangers, modifications, etc...

thanks
EDB

Captain Goddammit · Post by **Captain Goddammit** » Fri Apr 25, 2008 8:11 pm

I motorized my bike for Burning Man '01. I don't have a lot of real info for you since I only rode it that week, but here's what I remember.
Mileage seemed great, I had a little canteen for a gas tank, and it ran practically forever on it.
It was a little old weedeater motor, I don't remember the displacement. It didn't have enough power to go up a hill, and just barely sustained itself on level ground. It did take most of the work out of riding, though. I could cruise forever on it.
It was driving the front wheel, which was great. Since the pedals drove the rear wheel, it was an all-wheel-drive bike and made it though soft playa when I couldn't get through on pedal power alone.
It was really cool, and I'd have kept it around if I ever used a bike for anything.

I'd say get as much motor as you can, power is in short supply and gas isn't an issue in this small of a quantity.

Dustdevil · Post by **Dustdevil** » Fri Apr 25, 2008 8:41 pm

I have no personal experience, but this one really looks nice.

http://www.revopower.com/the_wheel-gallery.html

stargeezer · Post by **stargeezer** » Fri Apr 25, 2008 9:51 pm

OK, I have not thought this all the way through, just an idea that may be worth investigating!!!

What would happen if you widened the front forks and then replaced the normal front wheel with a rear one that still had the multi-speed sprocket on it? Mount the engine just under the handlebars and connect it to the wheel with a normal bicycle chain, shifter, and derailer. This would give you lots of gear variation for the hills, and when the engine was not running, the front wheel would just freewheel, just like the rear one does when you are coasting.

I may have to play with this one, both with a small gas engine, and a small electric one.

gyre · Post by **gyre** » Fri Apr 25, 2008 10:11 pm

You could drive the rear.
Seems to work best using an internal gearset like the SRAM.
Some 3 speeds are tough too.

Dustdevil · Post by **Dustdevil** » Fri Apr 25, 2008 10:14 pm

Taking into consideration the engine speeds, you would need a gear reduction unit. The sprockets are relatively small on the hubs to which you are refering. It could possibly work with an electric motor but they also spin at a relatively high rpm. There are small engines that attach to the forks and use a rubber drive wheel that rubs on the front tire. If you look at the size between the tire and a small rubber wheel turning it, you will find a reduction of close to 14:1. A derailure is reasonably reliable at the low speeds at which a cyclist pedals, but for the higher speeds of an engine it would most likely become problematic. With enough thought you can make almost anything work, but it seems like there must be a company that has already done the engineering for you.

gyre · Post by **gyre** » Fri Apr 25, 2008 10:23 pm

I have been mostly looking at geared electric bikes.
Everyone who has done one has avoided the derailleur for strength problems and the gears are designed for chains to come off.

I can't recall if the one I like best had a larger gear on the hub, but it had the motor mounted high enough that it could run anything needed at that end.
I think SRAM has a large number of ratios which is another advantage.
I can't find the website with the one I'm most impressed with, or I'd post it.
It was custom made but the design allowed great freedom in choosing parts like the motor.

EvilDustBooger · Post by **EvilDustBooger** » Sat Apr 26, 2008 11:55 am

Captain Goddammit wrote:It was a little old weedeater motor,.. It didn't have enough power to go up a hill, and just barely sustained itself on level ground. It did take most of the work out of riding, though. I could cruise forever on it.
It was driving the front wheel, which was great. Since the pedals drove the rear wheel, it was an all-wheel-drive bike .

I'd say get as much motor as you can, power is in short supply and gas isn't an issue in this small of a quantity.

This sounds fantastic for the Playa. I rode around in BRC a few years ago
on an electric version of one of those front wheel drive types that had a simple lever that would put a drive wheel against the front tire. It was pretty nice on the flatness out there, but still bogged down abit in the trafficky powder ponds around the Esplanade and such.
What I`ve been looking at is some models that require mounting a sprocket on the back wheel opposite of your existing sprocket. The engines go up to 80cc and it requires drilling/mounting, etc...
...even has a gas tank similar to a motorcycle.
My challenge is going to be adapting kits made for 26" wheels and standard frames to a hybrid diamondback maravista styled bike.
The tires are just a bit wider than ordinary street tires which shouldn`t be a problem , but they are 28"ers and the bike frame is pretty thick in all the wrong places. I`m pretty handy in the shop, so I should be able to handle making some adaptations, but...
...I love this bike. And don`t want to jack it up with a system that is faulty or isn`t going to last very long. It`s important to me to have a sturdy "manual" function too because I take some pretty serious treks sometimes and I need/want the extra performance 28' tires and serious gears afford me. Should I save the worry, alter my dreams, settle for less,...maybe try this on another bike instead?
If I could just find a powerful enough, reliable enough front wheel unit I might just go for front wheel drive...
decisions, decisions.

Thanks to everyone for the excellent input.

EvilDustBooger · Post by **EvilDustBooger** » Sat Apr 26, 2008 12:03 pm

Dustdevil wrote:I have no personal experience, but this one really looks nice.

http://www.revopower.com/the_wheel-gallery.html

Very cool.
I wonder if it`s clunky at higher speeds or it affects the manueverability.
Looks very "Jetsony"

gyre · Post by **gyre** » Sat Apr 26, 2008 12:32 pm

I think it is better to have a dedicated bike for powered use.
You need more strength and weight.
I am thinking of using a manufactured electric and upgrading it.
There are some very powerful hubmotors out there if you go that way.
Some people use a low speed one at one end and a high speed at the other.
I want gears myself.

Here are a few types I've been looking at.
Beware the cheapos.
They can be very noisy even if they run.
Tidalforce is supposed to be great, if you can find one.

http://www.cyclone-usa.com/

http://cleverchimp.com/products/stokemonkey/

There is a similar australian design that seems very good.
Heinzmann makes great hubmotors.

Some forums-

http://www.bikeforums.net/forumdisplay.php?f=258

http://tech.groups.yahoo.com/group/power-assist/

http://endless-sphere.com/forums/index.php

http://www.pedelecs.co.uk/forum/

http://visforvoltage.org/

Some electrics
http://www.cyclingforums.com/

Mostly motors
http://www.fieldlines.com/comments/2004 ... 918/600/21

EvilDustBooger · Post by **EvilDustBooger** » Sat Apr 26, 2008 1:11 pm

Thanks for the links gyre.

Lots to look at.

I like the looks of that 500watt cyclone, but I also like the idea of
the simplicity of just gasing up somewhere and not having to lug/charge
the batteries.

...but the possibilities seem to be endless.

gyre · Post by **gyre** » Sat Apr 26, 2008 1:29 pm

Try an electric before you make up your mind.
There is something magical about whizzing along so quietly, especially at burning man.
You actually need bells for pedestrians.
They are more expensive to get into, but can be cheaper long term.
Lithium and the new advanced lithium batteries are available now and nimh is being dumped cheap sometimes.
Matched packs work much better, cost more upfront.

I have to get something I can use real world or I can't justify it.
The higher gas gets, the more cost effective though.
And I don't believe in electric cars, but a 70 pound bike can work.

There can be a theft advantage with the more subtle designs too, as they are hard to spot as powered.

Elorrum · Post by **Elorrum** » Sat Apr 26, 2008 7:18 pm

I found some interesting gas engine kits too, but that engine in the wheel is something else. I wonder how they could balance it so well, Is it gimballed within the wheel always staying upright? or spinning? or if the truing of the wheel would be a problem. still very cool, and the look of it is stealthier than a mini motor mounted like a small motor cycle, those can lead to official sorts of inquiries and delays.

anyway... I love the name of this one: The Skyhawk Stage !! Whopper Stopper at bicycle engines.com It's a 4 stroke kit, and maybe wouldn't have as high a whine? whopper stopper mounts inside the frame. bikemotor.com has various types, frictions drives, and rear rack mount chain drives.

I started with a simple plan. ha ha ha ha ha ! Now I have comepletely lost focus. darn the internet!!!!!

I like the quiet of the electric, but the charging issues get expensive fast. I'm thinking electric for home and gas for he playa.

Captain Goddammit · Post by **Captain Goddammit** » Sat Apr 26, 2008 7:43 pm

The front-drive setup, using a small wheel pressing directly on the tire tread, eliminates all sorts of issues, particularly gearing. It works great!
A small motorized wheel against the 26 or 28 inch bike tire provides the high amount of gear reduction you need.
There are, or at least once were, bolt-on motor setups like that, requiring zero drilling or modifications to the bike.
I'd definitely find one of those or make another if I was gonna motorize another bike.
The way to go is have a lever to lift it from contact from the tire to clutch it, or press it to the tire to engage. It's better than driving the rear wheel (or front wheel) with a chain/sprocket/freewheel; the motor becomes self-starting. You just get on and start pedaling, and it fires up and takes off! Anytime you want, in motion, you can clutch or unclutch. If you were to use a freewheel setup, you'd have to start the engine some other way.

By the way, for Burning Man motorized bicycles fall under Mutant Vehicle rules and licensing requirements... which really sucks... and I was chased after and told I could not ride mine back in '01.
It was faster and more maneuverable than DMV gold carts... uh... not that that mattered, of course...

gyre · Post by **gyre** » Sat Apr 26, 2008 8:56 pm

At the other end of subtle and silent, a friend of mine built this turbine scooter.
I have a good still photo if someone can tell me how to move it to this site.

i could have bought a larger turbine cheaper, used, but
since i really didn't have any experience with turbines, i bought a
new unit from Wren. it has autostart which checks the
glow plug, lights it, then runs the starter and feeds in propane-butane
gas til the thermocouple shows 100 C rise. it then starts to
feed in jet-a fuel til the revs hit 32,000.
then it runs it up to my idle rpm, about 80,000 rpm.
the gas runs thru a turbine which turns a max of 65,000 and
then into a gear reduction to give an output shaft max of
11,600 rpm and i timing belt reduce it 2:1 from there.

i built a small motorcycle from tubing, powered by electric. (road legal)
after a couple of years i changed it over to a Wren turboprop engine power.
model aircraft type, about 8 hp.
makes a lotta noise and draws a crowd at bike week, daytona.
n1 is 160,000 rpm, n2 is 65,000 max. output shaft is 11,800.
look at wren, the MW-54 turboprop engine.