Project General Lee - RC Powered BMX bike

[Metallover]

I've wanted a motorized vehicle for the longest time now. After failing with gokarts and other things, I think I'll try my hand at an e-bike with some experience up my sleeve. The bike I've chosen is my old DK general lee 20" bmx bike. It needs a rear wheel because the old hub lost a bearing. The crank lost a bearing too, so I replaced it with a better crank. I hope the front bearing hold up, that's all that's left. :lol:

My other hobbies are RC cars and Spud guns. I have lots of experience with brushless stuff, LiPos, Propane and PVC.

I'm using a HXT 250kv 63-54 outrunner with a Hobbyking SS Series 85-95A ESC aka suppo 100a. I'll be running 24v 10ah SLA for testing then I'll probably go for a 9s 10ah LiPo pack once I get a new controller.

I'll be using the ex-crank location for the jackshaft. I don't plan to have pedal assist at the moment. I've got all the gears I need. One reduction will be about 5:1 and it's the old gears from an electric scooter; The second reduction is ~3:1 and it'll be the old freewheel going to the old crank sprocket. That will give me a total reduction of about 15:1, which should get me about 32mph on 33.3v and 22mph on 24v. I hope to get 1500-2000w from my system.

Here are some pictures

the bike in it's current state-

The motor and Controller

some of the gears and my jackshaft needing a lathe

And here is my to-do list
-buy a rear hub and spokes and assemble rear wheel (already have everything else)
-design and make motor mount, battery trays, throttle assembly (servo tester)
-attach gears to jackshaft
-attach sprocket to rear wheel
-Get a chain for jackshaft/wheel connection (old one's trashed)
-attatch footpegs
~possibly add disc brake to front to make bike more dangerous

here are my questions-
Do you think it'll work?
Range estimates on 10ah 33.3v lipo?

 

[recumpence]

Will it work? Well, it CAN work with what you have. It all depends how well you fabricate the remaining items.

Range? I would say a solid 10 miles of not pushed too hard, maybe 15 miles if you are careful.

I am looking forward to what you come up with.

Matt

 

[spinningmagnets]

As long as you're buying a new rear hub to lace up. I recommend paying a few bucks more and getting a disc brake hub. I'm not saying you should put a disc on the left, but it will come in handy later. Having those threaded holes on the left creates many options for the future. Especially if you're interested in RC builds...

 

[Metallover]

Awesome. I need to get a 3/4" jackshaft 6" long. Where is the best place to get a rod like that?

Also, this forum seems to be based in the UK? I'm from the US, and I'm guessing everyone uses metric measurements here.. The shaft in metric measurements is 19.05mm and is about 150cm long.


I'll look into that hub too... I need one with 48 total spokes, the "spoke mounts" around 2 inches apart and 3" in diameter, and the rear "fork" is 4 1/4" apart. I need a 1/2" shaft too, which I already have. Where's a good place to get a hub? Online or bike shop?

 

[spinningmagnets]

Here's a Kart supplier link, they have 3/4" shafts, etc, It'll get you started, but look a while before you buy.

http://endless-sphere.com/forums/viewtopic.php?f=10&t=9695&start=30#p168210

You might want to look at Muds build?

http://endless-sphere.com/forums/viewtopic.php?f=28&t=9838

And here's the resources thread, (found as a stickie, permanently at the top of Non-hub index)

http://endless-sphere.com/forums/viewtopic.php?f=28&t=7192

Endless-sphere is run my "Knightmb" and is a website hosting company that is based in Tennessee (USA), he likes E-bikes and when the old Visforvoltage site went down, he hosted a new site that has become the biggest and best. There are posters from every continent.

http://endless-sphere.com/

 

[12p3phPMDC]

I like it.

I've thought about using the crank as a jackshaft for a
recumbent using the back half of a bmx or mountain bike
swing arm suspension assembly.

As far as the footpegs go, are you planning on putting them
where the crank used to be supported by a brazed/welded on
footpeg mount? or just footpegs in the rear?

A three speed rear hub wheel assembly would give you
a .75 to 1 gearing in first, 1:1 second, 1.33 to 1 in third.

With the high power high torque builds, gearing doesn't seem as important.
But with a lower power drive, That reduction could be nice.
You would get a 20mph 30mph 40 mph setup.
If you did a shimano inter3, you could have rear disc brake mount as well.

 

[swbluto]

Also, this forum seems to be based in the UK? I'm from the US, and I'm guessing everyone uses metric measurements here.. The shaft in metric measurements is 19.05mm and is about 150cm long.

:lol:

What we have here is superior people and superior people use superior unit systems.

Just joking, but a lot of the RC motor stuff from hobby city seems to be in metric and there are people from everywhere in the world here, so metric tends to be a more "universal language" than the imperial system (w/ inches and feet, oh my!) and it tends to be more readily understandable by everyone. Having said that, though, I'd guess that U.S. citizens make up approximately 2/3rds-3/4ths of the active member population

 

[Metallover]

I am not going back and fourth about keeping the pedals and adding a drive system instead of using the crank case for the jackshaft.

I'll probably go find an old 20" wheel to complete the bike. I don't need anything fancy... This will be a somewhat-redneck build so who cares. :wink: I plan on welding on the footpegs, although I don't have a welder. I guess I'll have to weld with a friend. Or I could also try brazing, I'll have to research that though..

And thanks for the explination on metric/standard.

I hope to get some progress made before the end of the week.. 8) I hope. :|

 

[Metallover]

I got some news on my bearings for my jackshaft. They're not 3/4", but they're 20mm. crap. Not sure if I'll find a 20mm shaft or think up a different setup.

 

[Miles]

20mm shafts here, if you need: http://www.sdp-si.com/D785/PDF/D785Shaft003.pdf

 

[fechter]

Are you going to mount a spud gun on the frame too?
I prefer MAAP gas to propane btw. Much better at night, big orange fireball.

 

[Metallover]

LOL. I guess I could hold the spud gun.... The reason I use propane is because it's cheaper and I got 8 free tanks when my aunt passed. :wink: Mapp gass is also more expensive... But if the two were the same price, it would be MAPP gas all the way!

Thanks for the 20mm shaft link. I don't need it at the moment, because I found a shaft that will work for now. I bet this'll fail and I'll need a real shaft though... It's a 3/4" threaded shaft and I made some redneck bushings to make it fit snug in the bearings. I hope it holds up. I also got a way to mount the freewheel. I took a nut and grinded it down for half an hour until I could pound the freewheel in. I'll probably use some JB weld to bond er permanetly. I'll tighten one nut against this one so it won't turn with the torque.

I still have to figure out how to mount the other gear on the shaft and get a rear wheel/chain to finish the back of the bike up. Then I'll just have to mount my motor and primary drive.. 8)

 

[Metallover]

I went looking for a rear wheel today. Looked at the good wills and second hand stores. Nothing. However, I saw a couple kids walking holding a bicycle wheel that looked about the right size. I asked them how much they wanted for it and they said it wasn't for sale. :lol:

I ended up spending $5 one a graphite driver, a graphite 3 iron, and a bowling ball case that included a free bowling ball and a rosin bag. $1 for the ball and $2 for each golf club. Now I can go golfing. Two clubs should be enough... 8)

Anyone know where I can locally get a used rear bike wheel/bike parts? I'll look anywhere. Would bike shops have old crappy bikes?

 

[spinningmagnets]

Just after Christmas and before January 1st, the thrift stores are flooded with used bikes of all sizes. The kids got new bikes, and the dad wants the tax deduction. Craigslist, yard sales (but get there very early on Saturday morning).

 

[Metallover]

Reviving this project.

Got some money and new motivation now. I'm going to use new electronics as the ones above are on my pocketbike soon to be scooter.

I couldn't decide on 6 or 12s lipo, so I think 9s lipo is a good comprimise. I'll get two 6s lipos and two 3s lipos. I can make a 9s 10ah pack, a 12s 5ah pack, or a 6s 15ah pack.

I am thinking a hubmotor or more likely another outrunner. If a hub motor would be better, let me know. maybe a 9c? I'd run the 12s sentilon controller with an outrunner.

Here are my quick motor choices, let me know if you have something else that would work good-

HXT 63-74 200kv - http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idproduct=3890
HXT 80-85-B 170Kv - http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idproduct=5141

Let me know if anything else would be a good choice. 9s isn't only a little cheaper, but it should be less taxing on the controller and motor. I think 9s might be a little much for the 200kv motor, but the 170 should be right in the ballpark. I also could have chosen the monster 130kv, but it looks a little hard on controllers.

I want to hit 30-40mph with this setup. For the drive system I am thinking #25 chain or a belt. I'm not sure where to get gears and cogs, doing a 1 stage or 2 stage reduction....

Let me know what you think

 

[mud2005]

the link Miles posted earlier for SDP is good for #25 gears and timing belts and pulleys, if you are going for quick acceleration I would say use all chain drive, otherwise use timing belt for the first reduction to reduce noise. I dont care much about acceleration so I'm trying all belt drive on my next build. I use 5mm HTD belts and pulleys.
For pegs maybe you could use rear axle pegs until you get a chance to weld something better?
I dont know outrunners, do you have anything against inrunners? if not anything made by astroflight is top notch.
also just curious is it metallover cause you love steel or heavy metal?
good luck

 

[Metallover]

Hey mud! Saw your build. Helped me out a lot.. I own a few astrofligt products myself for my RC vehicle addiction. I have a powersupply and a balancer. Both are great, the balancer is one of a kind. No one else makes a "blinky" balancer.

I have owned a ton of brushless motors, mostly inrunners. I have a micro t with an outrunner directly attached to each of the rear wheels and I had a crt .5 with an outrunner in the middle. All my other electrics (savage, revo, vendetta st, vendetta buggy, crt .5, jato, stampede, evader, and so on) have inrunners. I chose an outrunner because of the price mainly. They also have huge torque by their design. I'm sure some inrunners have godly torque too, but outrunners are more widely availible.

My name is for metal music. Love the stuff. Weather it's in the weightroom or on a casual drive, metal is the way to go. 8)

I'm contemplating a single stage reduction or a dual stage. Any experience with both? A single stage has the simplicity appeal but the dual stage has the "you can't go wrong" appeal. It seems like a single stage would be easier to make too; less fabrication.

My motor will probably have a 10mm shaft, which means I can use an 11t sprocket and #25 chain. With a 170kv motor on 9s lipo, I could gear around 11/110 (9:1) for a top speed of 33mph. If I get the itch for speed, I could bump up to a 12t and get 36mph. The 110t sprocket from sdp costs $43 and is 9" in diameter. Sound like a plan?

I would probably get some machine work done on the large sprocket (or do it myself if I can find the right tools). How much do you think it would cost to get some holes drilled in it to lighten it up?

edit - might go for the 125t sprocket because it will give me room to gear down if I get a 12s system or I need to gear lower. Mud, you said it was too big?

 

[Metallover]

Thinking about picking up this rear wheel. Looks really nice and it's not much more expensive then some of the hubs. It's all black too.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350147234369&_trkparms=tab%3DWatching

Good price? Any cheaper flip flop hub/wheels out there?

 

[Miles]

Why do you want a flip-flop hub?

 

[Metallover]

It seems like the easiest way to have pedal power on one side and a freewheel for the sprocket on the other side...

There's an easier way isn't there. :| :lol:

 

[Miles]

A flip-flop is not what you need..... Both sides have RH threads, so the left hand side one will unscrew.... :wink:

You need a bi-drive/dual-drive hub.

The best ones like the DK Dual-Drive are now discontinued

 

[Miles]

http://www.profileracing.com/estore2/index.php?productid=16

http://www.profileracing.com/estore2/index.php?productid=20

http://www.evdeals.com/USPD%20Drive%20Parts.htm

http://www.staton-inc.com/Results1.asp?Category=21&offset=75

There's also this, but I've no experience of it:
http://www.grubeeinc.com/USA/HD%20Rear%20Axel%20kit.htm

 

[Metallover]

Hey, just looked at my old hub and what do you know, it looks like a dual drive. It's got threads on both sides and as the are in rough shape, I should be able to get the freewheel on and mount a sprocket. It's made by DK.

Thanks for the links!

edit - here's a link to my hub - http://www.angelfire.com/pa5/larrysbikes/wh104.html

Says it accepts drive to both sides so I'm guessing it should work if the threads aren't stripped.

 

[Miles]

I'm not sure....

Is the left-side thread left-handed (mirror image of the right-side)?

Does it have the adaptors?

 

[Metallover]

The threads are so messed up I can't tell which way they are going. I might just file the threads off and jb weld er on there. There are no adapters for it... That looks like a mountain bike hub, and mine is the BMX version, although they might be the same model...