Looking for advice on 20" Cargoish build

[Lupulin]

Hello ES!

So I am looking to get into the parts ordering phase of my build. I have a Yuba Mundo with a StokeMonkey 36V. My problem with the Mundo is that it is just more bike than I need. It's cumbersome for me to put in the garage and get around, I never use it close to its capability. I like how quiet the SM is, but looking for less of a tractor feel. So its time for a new bike!

After reading Wesnewell's thread on providing useful information to get better responses:

1) Desired Max Speed (flat, no wind): 35 MPH (Cruise 25-30 mph with a little for reserve)

2) Desired Max Range (flat, no wind): 30 miles @ 25mph (This is larger than I need, but I think I would rather have a bigger battery that will last longer and still be usable after a few years with the range shrinking. I realistically only need probably 20 miles)

3) Preferred Wheel Size: 20" 406

4) Brake: Discs or Drum/Disc (f/r)

5) Rider weight: 190 Lbs

6) Terrain: I'd say mostly flat with short hills under 20%?
(There are some longer hills here I'd like to be able to scoot right up, specifically College Way here in Bend, OR to be able to get up to the Community College. I wish I knew if there was a way to post street/hill information from the DOT or the city, but I have no idea how)

7) Budget: Somewhat flexible. I would rather do this right instead of skimping, but saving $$$ is always good.

Plan thus far:

Motor: Either a 6T Mac or low turn Leaf motor in a fairly wide 20" 406 rim I will build.

Controller: unknown (EM3EV)

Battery: 18650 of sufficient size/C rate to meet needs (EM3EV 25r? Thinking I will need to run it at 72V to get the top speed I'm looking for)

Is this enough info to get started?

I'm super excited about this project. I've been wanting to build a frame for years. Having a fairly powerful motor in a 20" wheel, I'm hoping its a blast!

I know later on I will also need some help choosing the correct CA, throttles, etc. BTW, I have seen people on ES getting 3 position switches. What do the use them for? They don't use it as a throttle (50,75,100%???) do they? I like having a variable throttle on my Mundo.

 

[Jonathan in Hiram]

I put up a post recently with an interesting "cargo-ish" frame that speaks to a lot of the negatives you mentioned, looks like it would be a fairly easy fabrication as those things go. I'd make the front triangle a bit bigger and stick a nice big battery in it, that would still be low enough and the weight would plant the front wheel when you are riding empty.

If you like the quiet how about the Leafmotor and a Grin sine controller?

https://endless-sphere.com/forums/viewtopic.php?f=3&t=73098

 

[dogman dan]

Sounds a little bit like your idea is similar to one of my frame experiments, the trash runner.


https://endless-sphere.com/forums/viewtopic.php?f=6&t=66005

I was trying to make a 50 buck version of the edgerunner frame. It turned out great, except for I got the rear wheel dropouts crooked, or they bent right away. And, the frame I started with was so bad a fit for my body, I really couldn't stand to ride it long.

Re the motor, just about anything with 1000w is going to rock in a 20" rim. You're on the right track there. You can go for a fast motor like the 6t in 20" rim, and have plenty of torque to get up hills, and nice take offs from stop signs. That was the one thing I really did like about the trashrunner.

The other reason I stopped riding the trash bike, was I put the motor I had on this. Same great performance in 20" rim. It's a 7 turn 9 continent type motor. Not a "fast" motor, but I was surprised how fast it is, since the bent bike has low wind resistance.

You might just want to consider a bent... If you weld, duplicating this re bike design is pretty easy.

When I need to carry cargo, I just add a bob trailer now. My enormous long cargo bike hardly gets used at all nowdays.

 

[Lupulin]

I put up a post recently with an interesting "cargo-ish" frame that speaks to a lot of the negatives you mentioned, looks like it would be a fairly easy fabrication as those things go. I'd make the front triangle a bit bigger and stick a nice big battery in it, that would still be low enough and the weight would plant the front wheel when you are riding empty.

If you like the quiet how about the Leafmotor and a Grin sine controller?

https://endless-sphere.com/forums/viewtopic.php?f=3&t=73098

Hi Jonathan,

I saw your post and I like the bike, but I don't think that will solve my storage issues.

Right now my bike is just too long (and wide with the 'wide load bars' or whatever they're called, I'll take them off soon thou). I am interested in something about the size of a 3/4 mundo frame and the smaller wheels. About the size of the Juiced Riders ODK, but I'm just not fond of that frame, and I would like to carry the battery in a Triangle bag.

I am leaning toward the Leaf 1500 watt (I forgot to specify). As far as the Grin controller, that sounds great, except I don't think I'm up to getting it to work. Even though this is ES, I'm more of a plug and play guy when it comes to the electronics. I can cut, miter and stick metal together, but when it comes to modding electronic stuff, errr, not so much!

Thanks for the link.

 

[Lupulin]

Sounds a little bit like your idea is similar to one of my frame experiments, the trash runner.


https://endless-sphere.com/forums/viewtopic.php?f=6&t=66005

I was trying to make a 50 buck version of the edgerunner frame. It turned out great, except for I got the rear wheel dropouts crooked, or they bent right away. And, the frame I started with was so bad a fit for my body, I really couldn't stand to ride it long.

Re the motor, just about anything with 1000w is going to rock in a 20" rim. You're on the right track there. You can go for a fast motor like the 6t in 20" rim, and have plenty of torque to get up hills, and nice take offs from stop signs. That was the one thing I really did like about the trashrunner.

The other reason I stopped riding the trash bike, was I put the motor I had on this. Same great performance in 20" rim. It's a 7 turn 9 continent type motor. Not a "fast" motor, but I was surprised how fast it is, since the bent bike has low wind resistance.

You might just want to consider a bent... If you weld, duplicating this re bike design is pretty easy.

When I need to carry cargo, I just add a bob trailer now. My enormous long cargo bike hardly gets used at all nowdays.

Dogman,

Thanks for the reply and your experience with the 20" wheels.

My original experience with 20" came on a recumbent, RANS Rocket. I toured the pacific coast on that bike with a BOB. Loved the 20s, the BOB was OK. I find it kind of hard to wheel around a bike with the BOB attached. I also like being able to pick things up if I happen to come upon them.

I am leaning toward the 1500 Watt Leaf motor. I'm looking for ideas on what Voltage I will need to run it at to achieve my performance goals stated above. Any thoughts on a battery, battery supplier or controller?

 

[dogman dan]

Well, 1500w sort of pushes you towards at least 48v. But 60v might be what you need to reach a particular target speed in 20" wheel. It just depends on the winding speed of the motor. 450 rpm (on 36v) should be pretty fast on 48v. For sure to go as fast as you want, you can't use a slower motor. Any controller capable of 48-72v would give you the range to pick a battery voltage that suits your desired top speed the best. Hard to beat just going with a grin controller and CA, or alternatively, any controller that can still take a DP cycleanalyst.

Battery supplier is a tough one, some will say RC lipo. It is still about the tops for maximum voltage flexibility, cheap cost, etc. But charging and balancing lipo can suck, and boy is it ever inconvenient to have the house burn down.

Battery size, should be possible to do 30 miles at 25 mph minimum, on 48v 20 ah, but 25-27 miles might be the real result, especially if the bike has big high drag panniers on it. Calculate 25 mph using 35-40 watt hours per mile.

The Odk is the other frame I was sort of imitating, with my cargo bike experiment. Find a steel frame you like, and lengthen it 6" if you want it longer, but not too long.

I followed the trashrunner experiment with this bike. I only stretched it 9", the maximum I could do and still have its wheels fit onto my hitch mount bike rack.
View attachment 1

It might be, that with a 20" wheel, all you really need is the same total length as a regular beach cruiser, just moving the rear axle back so the back side of the 20" is the same length as a regular bike.

The cruiser bike fits a whole lot better in my garage than the previous cargo bike, which had about 16" of stretch.

 

[Lupulin]

[/quote]

Well, 1500w sort of pushes you towards at least 48v. But 60v might be what you need to reach a particular target speed in 20" wheel. It just depends on the winding speed of the motor. 450 rpm (on 36v) should be pretty fast on 48v. For sure to go as fast as you want, you can't use a slower motor."

Is'nt John in CR on a bit of a Jihad to debunk this fast wind vs. slow wind motor myth? I'm not sure I understand everything that he is saying, but trust he knows more about these electric motors than I do. I am sure he is a smaller wheel is better proponent.

"Any controller capable of 48-72v would give you the range to pick a battery voltage that suits your desired top speed the best."

I agree, but I am considering using dual 36/48/52V depending on where I go with the batteries

"Hard to beat just going with a grin controller and CA, or alternatively, any controller that can still take a DP cycleanalyst. "

I will definitely be getting a CA, just which one, and what's the difference between them. I would like to have regen, since there doesn't seem to be any reason not to have it if you are using a DD hub

"Battery supplier is a tough one, some will say RC lipo. It is still about the tops for maximum voltage flexibility, cheap cost, etc. But charging and balancing lipo can suck, and boy is it ever inconvenient to have the house burn down."

Burning down the house would be a bad thing. No Lipo, I have no experience and would rather go with 18650

"Battery size, should be possible to do 30 miles at 25 mph minimum, on 48v 20 ah, but 25-27 miles might be the real result, especially if the bike has big high drag panniers on it. Calculate 25 mph using 35-40 watt hours per mile."

Excellent! This is the kind of info I'm looking for!

"The Odk is the other frame I was sort of imitating, with my cargo bike experiment. Find a steel frame you like, and lengthen it 6" if you want it longer, but not too long."

Nope, building from Tubeset

"I followed the trashrunner experiment with this bike. I only stretched it 9", the maximum I could do and still have its wheels fit onto my hitch mount bike rack.
View attachment 1"

Definitely closer to what I'm looking for

"It might be, that with a 20" wheel, all you really need is the same total length as a regular beach cruiser, just moving the rear axle back so the back side of the 20" is the same length as a regular bike."

The dual 20" will allow me to do just that, stretch the distance between the axels out without necessarily going to a "longtail" style bike

"The cruiser bike fits a whole lot better in my garage than the previous cargo bike, which had about 16" of stretch."

I think we are on the same page

 

[Lupulin]

Oops, I didn't quote that as well as i had wanted too. I hope people can read it and not get too confused!