Home assembled electric Yuba Mundo

[shawname]

This is my home assembled electric Yuba Mundo.



I wanted an ecargo bike that would go 60 miles on a charge and tote a weeks worth of groceries and my girlfriend- all at the same time! My needs were more demanding than the products on the market could meet so I chose to assemble my bike.

I bought a Yuba Mundo frame with panniers and a front basket. I used a Ping 36 volt 30 amp battery and a 500 watt Golden Hub Motor that I have had on several other ebikes. I bought new Schwalbe Fat Frank tires. They are cushy and support 330 lbs per tire. I used a 7 speed internal hub that I had on another bike, and a 3 gear chainring in front. I added a car headlight sized 2200 lumen LED front light from Super Bright LEDs, and an LED truck flasher on the back. I converted the voltage to power the LED lights from 36 to 12 using a Green Galaxy Dc to Dc convertor from Thunderstruck motors. The lights burn just 20 watts and add enormous visibility and safety. I use a Cycle Analyst as an energy gauge, and find it invaluable.

The battery weighs 25 lbs and is mounted in the front basket. The basket is rated for 50lbs. It helps balance out the weight when the tail of the bike is loaded. I would have preferred to mount the battery lower, but I needed extra space to carry a larger battery, and chose the simplest option. Because the Yuba front basket does not turn with the handlebars, the weight is not noticeable once underway, and I can even ride with my hands off the handlebars. The front “hood” has proven to have other benefits, as there is plenty of space in there to manage the wiring and to store small valuables.







The bike has a tested range, (with no Leslie) and with me spinning the pedals, of 97 miles. The extra weight of Leslie and groceries costs 30% of my range. I met my design goals, and have a great car replacement vehicle.

Here is Leslie and I out shopping this morning.

I am building a 5 amp charger for the 36 volt Ping battery that will allow it to be charged directly from photovoltaics or a 12 volt battery array. I should have the first prototypes finished in a few weeks and will report back.

Now I look for opportunities to ride. I am reminded of when I first got my drivers license. I was always asking my mom if there was anything she needed at the store:

Mom, don't we need a loaf of bread?
No.
How about a half gallon of milk?
No!
How about canned ravioli? I don't see any.... Give me the car keys, I'll go get some for you!

 

[ohzee]

That looks great I love your build. I also am building up a yuba atm with a mid drive kit.

This will help me with my build. How do those tires fit they rub anywhere ? I would love a pair but was worried about clearance.

Also that front basket is it the one sold on yuba's site ?

I have one of the rear bags in route from yuba now.. that front basket is a lot bigger then I thought it would be.

Thanks for sharing.

 

[Chalo]

I used a 7 speed internal hub that I had on another bike, and a 3 gear chainring in front.

Careful of that gearhub. Whatever kind it is, you are grossly exceeding both the weight rating and the minimum input ratio for it. You're likely to spin the axle through its non-turn washer, break one of the sliding keys, or suffer some other consequence of overloading. I had these problems with my hub when I weighed about 375 pounds (approximately as much as two people), but I was running 40/20 primary gearing. Put your lady on the back and use 22/21 or 22/24 gearing to climb hills, and the bike won't have any better chance of resisting the consequent forces than mine did.

Make sure your rear dropouts are perfectly aligned, lest they add stress to an already overstressed axle that is also part of your gearbox.

If your gearhub ultimately doesn't pass muster, consider using a NuVinci or Rohloff gearhub instead-- either of which can tolerate much greater force and axle loading than any 7, 8, or 9 speed gearhub.

Chalo

 

[shawname]

Hi Chalo,

I agree. I built the gear hub into a Sunrim "Big Mammoth", which is very strong. I am not stressing the wheel beyond it's limits, but the inner workings of the hub. I rode a Rholoff hub over 6000 miles since October of last year
in Europe and beyond, with no problems. But I did meet another touring cyclist running a Shimano internal, and he had replaced it twice. It broke again while I was cycling with him.

TO mitigate this I start with the electric motor and pedaling both. When riding with the motor, I am doing just a little more work than spinning the pedals- about 60 watts worth!

Thanks for the tip on the axle alignment. I will check to be sure that the axle is centered.

Shawn

 

[shawname]

That looks great I love your build. I also am building up a yuba atm with a mid drive kit.

This will help me with my build. How do those tires fit they rub anywhere ? I would love a pair but was worried about clearance.

Also that front basket is it the one sold on yuba's site ?

I have one of the rear bags in route from yuba now.. that front basket is a lot bigger then I thought it would be.

Thanks for sharing.

Hi Ohzee,

The Fat Franks are perfect. No rubbing. I paid around $30 per tire, a good buy for Schwalbe's- my favorite tire manufacturer. They have the highest load capacity too.

The front basket is Yuba's and is very well built. It seems expensive, but it is very solid. You could probably carry 100lbs in it without bending it! The attachment to the frame keeps the steering light.

 

[Ykick]

Nicely done! Frame mount cargo rack is dope! Similar to frame mount motorcycle fairings...

All I can suggest you might need would be fenders/mudguards, if it rains often where you ride? Enjoy time spent with the lovely lady! ('was gonna say something about "riding" but nothing sounded quite right?) LOL...

 

[shawname]

Nicely done! Frame mount cargo rack is dope! Similar to frame mount motorcycle fairings...

All I can suggest you might need would be fenders/mudguards, if it rains often where you ride? Enjoy time spent with the lovely lady! ('was gonna say something about "riding" but nothing sounded quite right?) LOL...

:lol: You are right, I used to have a motorcycle with a heavy front fairing with large pockets to carry things, and it was of course frame mounted. Never connected the two.

You might think it's a little lame to ride your girl friend around on a bicycle, but she says that she feels "pampered"
She enjoys watching her man work too. She never enjoyed riding around on my big BMW motorcycle. But she feels safe on the bicycle. Its her ride of choice, like mine. A sports car wouldn't be the same!

And I do need fenders. Might be hard to find some wide enough to fit over those Fat Franks at 2.5"..

 

[Ykick]

2.5" might be tough for Planet Bike fenders. I've used em before on 2.25" rubber and they didn't look like they'd completely cover tread on anything wider? Cruiser bicycle component suppliers might be a good place to look for something slightly wider? Your rear wheel is damn near enclosed anyway but something for the front will come in handy once the rainy weather pattern hits.

Very inspiring though, 'might start planning one of these for the missus and me? I've gotta low speed wind front motor looking for a cargo bike?

Enjoy!

 

[ohzee]

Ah yea I totally missed the fact that the fenders were not on there.. I take it the bike tires were to big for them ?

That's what i meant by fitting , but I failed to be very observant.

 

[shawname]

Ah yea I totally missed the fact that the fenders were not on there.. I take it the bike tires were to big for them ?

I just never tried them on! I have some on another bike.

Ok, returned from measuring. The Planet Bike fenders are 2.25 inches wide, the Fat Franks measure 2.5 inches. If you hold the PB fenders up over the FF's, the outer edge of the FF's protrudes. They look good though, and since water is thrown off tires from the center of the tire, they should work just fine.

The fender stays are a different story, you'd have to bend a bit them so they don't rub on the tire.

 

[dogman dan]

Holy battery box. You should have some nice range with that. At first I thought it might be a bit much weight forward, but not if you often ride with a passenger. But this way you don't lose any pannier space.

At some point though, you migt look into building a box on the rear rack. Somebody else here made a new deck that incorporated the battery that came out really nice. Might not work with this battery, but maybe in a few years when you are ready to replace this one.

I'm just one of those guys that tried a fork mount battery and didn't like it much. But your double dutch type basket would carry a lot better than a basket mounted to the fork and handlebars.

Very nice! Longtails rule for cargo, whether the wheelbarrowlike front tub type or the huge pannier type.

 

[ohzee]

http://yubaride.com/yubashop/product.php?id_product=70

yea if you look at that rack it nicely mounts to the bike frame away from anything that turns.

 

[shawname]

Holy battery box. You should have some nice range with that. At first I thought it might be a bit much weight forward, but not if you often ride with a passenger. But this way you don't lose any pannier space.

My thinking exactly. Those panniers get filled often, and I use ALL of the room. For example, I just returned from picking up two 5 gallon propane tank refills.

I'm just one of those guys that tried a fork mount battery and didn't like it much. Does your box swing witht the wheel?

No, it is mounted to the frame, and that makes ALL the difference. If the basket swung with the wheel, I wouldn't have done this design. Consider large faired motorcycles. Their fairing is mounted to the frame, and stays stationary when the handlebar swings. Established proven design, works well. It works better then I thought it would, that's one reason I wanted to post this easy solution.

 

[ohzee]

Yea I bet that front battery helps with the front hub as well to minimize slippage by always have a nice weight on the tire.

 

[dogman dan]

Backtracking and actually reading, I see that basket is a true double dutch type. So after my edit of my comment, now your's look odd. but it's my fault.

 

[shawname]

Hi Dogman,

I didn't want to use the back rack for the battery because I often have Lisa riding, and for kicks, sometimes a couple of adults or the neighborhood kids.

I have never had any "slippage" with my front hub motor. It's only 500 watts, for heaven sakes. :wink:

 

[tinyhelmets]

That is awesome! I've been rigging out my new Yuba Mundo. It's not battery powered, maybe one of these days... I've got two little ones to haul around and I've been looking into protecting the one up front with a fairing. If you have any ideas, I'd really appreciate it! Zzipper is the only company, so far as I've found, that makes them for upright bikes. It's a little pricy but as I'm watching our car-savings go up, I'm becoming a little more relaxed about splurging. Please check out my website: http://www.tinyhelmetsbigbikes.com.

Thanks!

 

[kevo]

Awesome build shawname, love your electric Yuba Mundo. Keep the posts up on its reliability!
Looks hell a fun and quite suited for your terrain.

 

[Samd]

Inspiring!

 

[shawname]

I've got two little ones to haul around and I've been looking into protecting the one up front with a fairing.
Thanks!

The newer Yubas have mounting holes for the front basket in the frame. They would be ideal for attaching a fairing. I would try goggles first! I enjoyed your website, keep riding. Now I'm thinking about doing an electric version of yours on my website.

cheers,

Shawn

 

[melodious]

Nice build!

That "breadbasket" is a nice design. When I see DIY stuff like this, it gives me more confidence to start my own. Yuba does sell just a v4 frame for $500 (+shipping/taxes). The rest is up to you and your imagination (and wallet). Haven't driven a car for 1 1/2 years now so my savings keeping inching up as well as my confidence since lurking here on E-S. I think my real hurdle to overcome is electrics, but my knowledge is starting to gel (I was a puddle of ineptitude only a few months ago) Wisdom will come when I start working on it.

 

[ryan]

Nice work!

 

[SamTexas]

Very practical build. I bet you get a lot of attention riding with a passenger and those two big panniers.

The bike has a tested range, (with no Leslie) and with me spinning the pedals, of 97 miles.

What was the overall average moving speed for the 97 mile tested range?

 

[shawname]

[/quote]
What was the overall average moving speed for the 97 mile tested range?[/quote]

Hi Texas,

I was going slow at 12 to 15 mph. I was also pedaling. I was trying to keep the burn below 200 watts/hr whenever possible.

Just returned from a fast (18 to 21mph) 40 mile errand and into a strong headwind one way, and I burned almost 20 watts a mile. With a a 1100 watt battery (36x30) that's a 55 mile range.

My Ping battery, rated for 30 amps, actually holds 32 amps, according to my cycle analyst. That Cycle Analyst is really really useful. It helps you know how much speed and headwinds cost you, and how much power you are contributing. The LED gauges that came with the hub motor are useless.

cheers,

Shawn

 

[teklektik]

Just returned from a fast (18 to 21mph) 40 mile errand and into a strong headwind one way, and I burned almost 20 watts a mile. With a 1100 watt battery (36x30) that's a 55 mile range.

My Ping battery, rated for 30 amps, actually holds 32 amps, according to my cycle analyst.

Hmmm - figuring 80% DOD and using the empirical Ah rating, 39.6v*32Ah * 0.80 / 20Whr/mi = 50.6 miles.

I'm running Fat Franks on Sun Mammoth rims and they are just about to spec 2.35" wide. They fit perfectly in standard Mundo fenders, no tinkering with the stays, and no rubbing. I did have to deflate the rear one to get the hub motor into the dropouts, though. The Mammoth rim was discontinued since it was identical to the Rhyno Lite and only a mm or so wider. The Big Mammoth seems to be a different animal...

Very nice looking build - You should get Leslie a set of the Mundo 'stoker bars' and 'soft spot' seat if she's going to be riding there much