ATV tire Bike Build (Mid Drive Hub Motor)

Working on a prototype for my company. Its an ATV tired ebike. We have been building small, FAST, electric vehicles for 2 years now, but this will be the first 2 wheeled. Defiantly new to the bike world, but well experienced with Motorcycles, ATV's and the small Electric Vehicles. We have a full shop with several CNC machines, Mill, Lathe, plasma, etc.

This bike will be similar to a Motocross bike (Suzuki, Yamaha, Honda, etc) but use ATV tires and an electric motor (And still have pedals, although mostly for legal compliance as a bicycle). Im starting the prototype using a 1000 Watt Hub motor, mounted just behind the seat, but we have a decent budget for this project so will probably try a few different motors till we have the power and reliability we would like.

Here is my start in autocad. Still a lot of this drawing isnt the way it will be, and a few items arent to scale, but its the basic idea.

Any input is appreciated.



--John

Got the forks, so Ill be machining the triple trees on the CNC this coming week. Have them all drawn up.

--John

John in CRs minimonster would suit this perfectly....

http://endless-sphere.com/forums/viewtopic.php?f=31&t=40859

Jay

ejay: That motor looks cool, possibly ill try it. First try will be this motor: http://www.conhismotor.com/ProductShow.asp?id=97

Theres another guy on here, with a big thread and it seemed to work well..

Ive had good results on our other small vehicles using 1000 watt unite motors. Can't kill the things. Been running 2 on a 3 wheel scooter type vehicle we make, 93 amps max shown in CA, and the things dont even get that hot. On another one of our machines that runs one motor, we have beat it to the point of 190 degrees F, and still the thing runs fine. But im ready to journey into brushless Territory.

Anyone care to chime in on hub motor like the one above vs the superkids BMS 1500 watt motor? So much smaller would be a lot easier to use. But im guessing heat buildup on the small BMS would be way worse than the hub motor.

--John

That hub motor has 2 speeds and when stripped down, it's not as big as you may think. Easy on controllers, also. I'm going to run mine on 74V Nominal. John has it in that redesigned swingarm, and HE is a heavy devil, running the mountains of Costa Rica.

Nice Harold....

Really, I could care less about the bike going over 25 MPH. I need torque, and torque, and more torque. Since it will be ridden off road, in the mountains, there are a lot of short steep climbs that require massive torque. Ill leave going 50MPH to the road bike guys -). 50MPH on a bike with ATV tires isnt somthing that would be that fun...

Cut some test cuts of the tripple trees on the CNC tonight....cut them out of wood to test fit (Love doing this, wood is cheap!). They fit perfect, but are a bit massive, so im going to build some more pockets into them....

--John

So basicly you're wanting to build a bile like a Hanebrink style? Sounds awesome.
The motor choice sounds fine. ultimatly, it all comes down to gearing.

I wouldn't run the motor power down to the cranks, because then you'll end up relying on bike chain, which isn't going to be up to your task. Raise the pivot to the motor and center it's axle inside the pivot with the torque arm on the swingarm. That allows a cushy suspension without the motor affecting the suspension at all avoiding the related issues that all motorcycles and mountain bikes share, including yours as drawn. Then run the token pedal chain up to the motor, with a freewheel there.

The Mini-Monster would be especially well suited to this application, partly because it's difficulty implementing it on a bike, and that's the extra width, which helps you due to the wide tire. With a good strong chain, then you don't have to fool with a rear brake at the wheel, and can just use the motor's drum brake. The other reason is the 2 speed. Running 74V nominal you simply gear to 25mph in high using an easy 2:1 to 3:1 chain reduction depending on your wheel size. Then in low, which is a switch in the windings to half the rpm/volt, you'll be able to crawl up the really steep stuff and retain good efficiency. With my 250lb on a 100lb bike and geared to a high speed of 50mph, I can climb 25% in low without issue, albeit on the street. Imagine what you can do with it geared down to half that top speed in high. It's a tremendous advantage over other motors, and the next best thing to a multi-speed transmission, which would be the ideal for your needs, but weight, efficiency loss, and wide torque band of electric motors make them largely unnecessary if you size your motor right.

Whatever motor you go with I can't wait to see your bike. I've been wanting to do a fat tire offroad bike for a while, though I'll probably take the easy route and go with a Mini-Monster in each wheel and smaller tires than yours.

John

http://www.instructables.com/id/Modified-childrens-bicycle/

This should have such a model.

Drunkskunk said:

So basicly you're wanting to build a bige like a Hanebrink style? Sounds awesome.
The motor choice sounds fine. ultimatly, it all comes down to gearing.

Click to expand...

Bike? what bike... let me look a bit more... nope... dont see no bike

Joe

Humm, not really. Quite different actually. I will not have a tube frame, turf tires, or a drive like the hanabrink. Cool bike, but im building more of a MX looking bike...

--John

John cr, can you PM me your number so I can give you a call to discuss?

Thanks

--John

Started the forks...

Im torn between 2 drive options:

1. Put a dual sprocket on the motor (Ill cut a little sprocket adapter and weld it to the motor)...one to pedal chain ring, one to rear wheel. The only freewheel will be on the pedal chain ring, none on the motor. The advantage of this setup is I can use the derailer and gears....but will the derailer and bicycle chain hold up to the kind of power im wanting (enough so that you can go up ANY hill off road...the wheel will spin or you will flip before you run out of power)

2. Have the motor drive a single sprocket on the left side of the rear wheel, and on the right side just use a standard bicycle setup. No freehweels necessary except the one built into the rear freewheel sprockets. Using this method i could use 8mm or stronger chain on the left (motor) side.

Really, what im wondering is whats the limit of the derailer and bike chain?

--John

Got the Forks done.....I machined the tripple trees using a rigid router with an aluminum bit mounted to my CNC table. Took around 10 hours EACH!








Im keeping all the pics here, so bookmark if you want to keep track: http://www.johnhasmorefun.com/misc/bike/

--John

Hey mate

greatly appreciate seeing this build process from scratch,, and awesome what a well equipped 'shop can do.

Joe

The front end is looking badass. That's looking like the kind of bike I need to build, ie one that makes a Hanebrink look like a kids toy.

Yea guys, its going to be sweet. And as for the shop....once you go CNC with one machine, kiss your bank account goodbye -). You want EVERY machine in the shop to be CNC. Love it -)

We are known for making unique, but "cool" little vehicles. Im all for the function before looks, but we always make sure the looks are going to get smiles and wows rather than laughs. Im sure after 6 months of fabrication, testing, and such we will have a sell-able product to offer to the market. Our big saying is, our machines don't break. Period. I mean that. If I can break it, back into R & D it goes. People spend big $ on their machines, and expect reliability. Thats what im going for on the bike. You can tell by the tripple tree, its going to be WAY overbuilt!

Can't wait till i have it to the point i can start testing motors....

--John

I get the hill climb bike idea , and the use of a ATV type wheel / tyre for the rear..
..but Why do you need such a Hduty front wheel ? ..
....Im imagining a trials type bike !

hillhater: To balance it....its the look we are going for. If I did a small wheel in the front it would look like a dragster....cool, but not what we want on this machine.

Funny you call the wheel heavy duty, actually its the most thin wheel made for atvs! I would *never* use this on a actual ATV...bend way to easy. But on the bike, its more than enough!

--John

Finished the right side of the rear hub tonight. Came out perfect (Although I was thinking i could have done a bolt connection to the wheel plate rather than have to tig weld it). Oh well.

Check it out:

[youtube]Kfzx8VYjVHA[/youtube]

Heres where im at now. Going to cut the frame on the CNC tommorow out of plywood for seeing how everything lines up and feels. One nice thing about my CNC plasma / router table is that its 4' x 4', so i have the ability to cut the whole frame side in one piece.



--John

Finished machining the rear hubs tonight. Took almost 50 hours of work to get them done, but they came out sweet. Ill get some pics up once I tig weld them up...

Hate to say it, since its a bad word here, but going to go with lead acid for now....six 22ah sealed batteries that we use in most of our machines. Want to go headway or turningy but the price (headway) and the fire risk (Turnigy) is forcing me to go lead acid. This is just the prototype, we will swap the lead for somthing different when time permits.

The thing should FLY. This golden motor sounds amazing on the bench.

Need to have it done, and painted before the end of the month, so ill pretty much be working on it 10 hours a day for the next few weeks. Its starting to look sick (even with the mock-up plywood frame). One more cut of wood for the frame and im going to cut the steel frame, which should only take about 3 minutes on the CNC. Ironicly, the frame and the big parts should go fast....just took me a while to machine the rear hub parts since they were so complicated!

--John

Mockup6....going with this. Got it all working out, so time to cut out of steel.

Nooooooooooooooooooooooooooooooooooooooooo... Not Lead Acid

Awesome work still, mate, a pleasure to watch it all unfold.

Joe