Virtual Build Project - Yuba Mundo Urban Transporter System

[Richard N]

Virtual Build Project - Yuba Mundo Urban Transporter System

Hello everyone, and thank you all for so many wonderful contributions and the wealth of knowledge to be found here at the ES forums.

I have been a lurker here off and on for some time now and just recently signed up for a membership in anticipation of building my first e-bike. The purpose of the build is to provide me with daily transportation and the ability to haul cargo and perform the every day tasks of grocery shopping and running errands. Basically I would like to essentially have a car replacement, wouldn't we all?

Now as I am still looking for work I can't very well begin buying new bikes and components for a build but to stretch my imagination and understanding, and spur on my enthusiasm for the project, I'd love to talk about it with others that feel electric bikes are able to fill the role that so many feel only a car can accomplish. Hence my idea for a virtual build, I'd like to bounce around ideas and find out from those in the know what configuration and components would turn the already great Yuba Mundo into the vehicle replacement it can be.

So here are is the list of requirements I would like to realize from a new V3.3 Mundo cargo bike:

• Range of 40~50km.
• Speed of 32km/h, (legal limit, faster is better but I don't need a rocket, say 50km/h as an upper limit).
• Ability to limit speed "on the fly" to meet legal requirements.
• 500W legal limit, (for as much as that relates, as I understand it this is a pretty arbitrary requirement).
• Climb moderate hills with a load in place, (as much as possible, unassisted).
• Carry & move as much of the weight capacity of the bike as possible 440lbs cargo + rider.
• On board charging.
• Strong reliable components.
• As weather and water proof as can be, looking for suggestions here as to how best to accomplish this.
• Disk brakes front and rear.

Some details about me:

• I'm pretty lazy most days, assume very little peddling (I'll probably do more but lets assume I won't).
• I'm a good sized dude, 6'1" 230~240lbs so we can probably subtract 100lbs of cargo capacity to keep things inside of the intended design specs.
• I'm comfortable with building my own battery packs and such, machining parts if needed, unless they are basic, would need to be outsourced.
• I'd prefer to build the best possible Mundo I can, I'm not saying "price is no object", but if I can do better for a little more cash it's preferred.

A heavy bike, likely to be heavy components, wanting to climbs hills with a load and not peddle, I must be crazy right?
I understand that compromises will probably need to be made in some areas and I'm prepared to accept that though it will be kicking and screaming all the way. I'm not married to the idea of any particular type of component or manufacturer at this point, but the aesthetic part of my brain does tend to favor a rear hub motor installation.

And because we all like pictures, here is a photo of the latest 3.3 version of the Yuba Mundo.

Thank you
Richard

 

[Richard N]

I hope I didn't post a silly thread...
I'll keep doing my homework and post what I come up with for a critique.

Thanks
Richard

 

[eli6452000]

I built a yuba last year from a bare frame. The main reason I did that was that disc brakes were not offered from the factory. Wanting disc brakes and a front rack basically meant redesigning the bike.

Now that disc brakes are an option you can order from the factory, my advice is to start with a stock bike.

Before I ordered, I came across a post warning about relatively rough workmanship, and I did not take it seriously.

If you order a bare frame, be prepared to face the head tube and the bottom bracket shell yourself, or know in advance who is going to do that for you. Also be prepared to re-tap every threaded orifice on the frame (there are a lot of these).

Since I am recommending the stock bike, I also recommend riding it for a while before you motorize it.


I am over fifty years old, and I have lived long periods of my life with a bicycle as my only transportation, as I am doing now. When mountain bikes first became popular and I started riding one, I considered them to be a magnitude of order increase in practicality. The long-tail cargo bike represents an even bigger leap forward.

After riding a yuba for a year, I love it. This is the best bike I have ever owned and the most practical transportation I have ever owned.

 

[Richard N]

I built a yuba last year from a bare frame. The main reason I did that was that disc brakes were not offered from the factory. Wanting disc brakes and a front rack basically meant redesigning the bike.

Now that disc brakes are an option you can order from the factory, my advice is to start with a stock bike.

Before I ordered, I came across a post warning about relatively rough workmanship, and I did not take it seriously.

If you order a bare frame, be prepared to face the head tube and the bottom bracket shell yourself, or know in advance who is going to do that for you. Also be prepared to re-tap every threaded orifice on the frame (there are a lot of these).

Since I am recommending the stock bike, I also recommend riding it for a while before you motorize it.


I am over fifty years old, and I have lived long periods of my life with a bicycle as my only transportation, as I am doing now. When mountain bikes first became popular and I started riding one, I considered them to be a magnitude of order increase in practicality. The long-tail cargo bike represents an even bigger leap forward.

After riding a yuba for a year, I love it. This is the best bike I have ever owned and the most practical transportation I have ever owned.

That's great news on your assessment of the Mundo, for the most part it seems to be right inline with what I've been reading in reviews on the web and from the blogging crowd. I really have developed a soft spot for cargo bikes and of all the longtail designs I've looked at the Mundo is the one that is hitting all of the right buttons for me, and it really doesn't hurt that it's on the lower end of the scale price wise either. Also I was absolutely planing on going with a complete bike.

I was ready to buy a cargo bike last summer and had settled on a Kona UTE as I had not seen the Yuba at that point, as luck would have it there was not a single UTE to be had anywhere in town. I did come across a smoking deal on a Batavus BUB though so I picked that up instead, it's a lot of fun to ride but 3 speeds on the hills is killing me slowly. Not to mention the itch to build an electric is getting pretty bad again.

I really want to do this right the first time so I plan on taking it slow and vetting out all of my choices as thoroughly as I possible can. That's sort of why I decided to start this thread, so I can get a good idea of which way to go and how to best direct my research and efforts. There is just so much information and so many varied approaches that at times I feel like I'm going in circles, do I go with a hub or mid mount, do I want LiPo or LiFePo4, 36 or 48 volts, how many w/hrs... and the electronics make my head spin. Five or six hours a day reading for the next few months should get me up to speed... somewhat.

Thanks for your opinion of the Mundo, I appreciate it.
Richard

 

[ryan]

My next build will be a longtail as well. Can you tell me more about why the Yuba is a better fit for you than the Kona? Either way I'll be following your build.

 

[spinningmagnets]

I am sad to hear that the Yuba Mundo has a few issues with factory threads and welds being messy. That being said, I have also heard that it is sturdy, and when used for what it is designed for, it works well. Its my understanding that the latest version has disc-brake mounts front and rear (a small extra cost to the assembly line), and the frame is "stoke-Monkey ready" from the factory.

I have read of many users who were very happy with the Xtra-cycle attachment, which make a hardtail into a long-tail bike. And also that the Xtra-cycle allows the Stoke-Monkey kit to be mounted. Though all buyers seemed to be happy, they did mention that there was some frame flex sideways with the Xtra-cycle. The Mundo was frequently looked at for an non-flex replacement frame, but it was a frustration to find that the stoke-Monkey would not fit earlier versions of the Mundo.

The medium "nut-bar" height means this is a reasonable male-female frame that neither would be embarrassed to be seen riding. I would classify the latest Mundo version to be a serious commuter frame. The weight means that (although it is very strong) you will be unlikely to pedal much without any E-assist, so any Electric-drive should be scaled to perform as an E-moped that can be pedaled a little, to extend battery-range, but pedaling without any power for any length of time is somewhat overly-optimistic.

If your roads are smooth, and your tires are fat, and you have a suspension-seat (such as the $130 Thudbuster)...you may not need a front suspension fork...and a robust steel front fork should last decades with no repair or maintenance ever needed.

I am pondering a similar system, and I don't have any suggestions for the electric part just yet, because there are so many options, and my most desired system has a motor driving a 3-speed rear hub. If it works out for me, it will not be an off-the-shelf plug-and-play system, so I am reluctant to promote it at this early stage. Since your hills are not too steep, a 9C clone such as the kit from cell_man is very affordable (has everything but the battery/charger), and using 48V would provide a reasonable amount of power and top-speed. I would check dogmans many kit reviews in the product review section, lots of good info that can be relied on to be accurate.

Best of luck with whatever you choose...

 

[Richard N]

My next build will be a longtail as well. Can you tell me more about why the Yuba is a better fit for you than the Kona? Either way I'll be following your build.

From a specifications comparison the only difference would be a little more length in the wheelbase and an adjustable stem, it really more about the way the cargo handling capabilities are configured. I prefer the rear deck on the Yuba over that of the Kona and the addition of the side cargo platforms along with the massive 85l panniers. I've also read from some UTE owners that Kona panniers are problematic with heavier loads in them, one man reported twice having them tear off of the mounting points, once with a 30lbs bag of kitty litter and another time with a 15lbs bag of charcoal.

Also my thinking is with the side platforms I can make some nice wood platforms that have a compartment on the underside that's a few inches deep which can hold battery packs or chargers, maybe tools or parts... I don't know yet but I'll think of some way to make a couple of pseudo trunks.

This is what I'm thinking of doing... sorry no fancy renders, just some paintCAD

And on a purely superficial level I just like the way the Mundo looks more than the other longtails I've looked at.

Cheers
Richard

 

[Richard N]

If your roads are smooth, and your tires are fat, and you have a suspension-seat (such as the $130 Thudbuster)...you may not need a front suspension fork...and a robust steel front fork should last decades with no repair or maintenance ever needed.

I am pondering a similar system, and I don't have any suggestions for the electric part just yet, because there are so many options, and my most desired system has a motor driving a 3-speed rear hub. If it works out for me, it will not be an off-the-shelf plug-and-play system, so I am reluctant to promote it at this early stage. Since your hills are not too steep, a 9C clone such as the kit from cell_man is very affordable (has everything but the battery/charger), and using 48V would provide a reasonable amount of power and top-speed. I would check dogmans many kit reviews in the product review section, lots of good info that can be relied on to be accurate.

Best of luck with whatever you choose...

Thank you.

I'll be adding a suspension post and a big cushy seat, I don't think I'll need a suspension fork but time will tell. The roads are not too bad here, lots and lots of freshly paved bike lanes and a really wonderful park corridor known as The Galloping Goose Trail.

Right now I'm almost sure that I'll need 48v 30ah, I'm still trying to work out how to size the battery pack. I don't have a GPS and can't find topo maps of the city so I's having a hard time judging the typical hill % grades, though I think I'm over estimating. I was fiddling with the calculator over at http://www.noping.net/english/ and with me and a fully load bike a 10% grade at ~15km/h would need 1638 watts, so I'm assuming this is the steepest I'll encounter under the largest loads and working backwards from there.

Cheers
Richard

 

[Richard N]

Okay, this is a fun little video and I just had to post it.

400lbs of bananas on a Mundo, that's 10 box at 40 lbs each... a heck of a lot of bananas!
The bike took the weight but the rider said it was about 100lbs more that he could handle. At the end of the video they tally up the bike, `nanas, rider, and added bits to be around 660lbs. 8)

[youtube]i7z7lUaIkeM[/youtube]

 

[Richard N]

Right, so I've been doing more reading trying to get a handle on sizing a motor for my future build. I think all I'm doing is confusing myself in the process.

I'm leaning towards using a Crystalyte rear hub but I'm having a hard time reconciling which one. A 5304 or 5305 offers lots of torque for climbing hills and hauling loads but as I read it, it's not really efficient running at 48v. How large a hit would I be looking at if I stuck with 48v?

I'm also looking at the Crystalyte 408 or 4011 @48v which should give me a higher efficiency but I won't get the same torque with out lots of current (I think). Would I be risking a shorter motor life span putting lots of load on a smaller hub like the 408?

I need some expert guidance here, what motor voltage combination is going to get me the best climbing hauling and characteristics, heavily favoring range over speed as long as I can get to the 32km/h legal limit.

I'm so confused...

 

[ryan]

If your sticking with 48v I'd use a bmc v2. Otherwise I'd up the voltage to 72v and run a 5305. The geared hub of the bmc will be very efficient with the lower power but won't last if you need to up the performance.

 

[Richard N]

If your sticking with 48v I'd use a bmc v2. Otherwise I'd up the voltage to 72v and run a 5305. The geared hub of the bmc will be very efficient with the lower power but won't last if you need to up the performance.

Ryan, thanks for the feedback.

I haven't really read much on geared hubs, as I'm still undecided about using regen, and I'm a little leery about nylon gears holding up over time. I'll do some reading and see what I can learn. I'm not necessarily tied to the idea of 48v, I'm more concerned about getting the best possible combination of climbing and cargo capacity along with range. If that ends up being 36v, 48v, or higher then that's the way I'll go.

My thinking was that by sticking with lower voltages I would be able to build larger ah capacity packs for less money, though I wouldn't be surprised if I'm in error with that thinking.

Cheers
Richard

 

[Lemlux]

First, let me say that I've ridden a 2010 Yuba Mundo and liked it. For those in the San Diego area be aware that Velo Cult Bicycles has 2 of these in stock which they advised that they would probably sell for $900 each. They say a customer ordered one and the factory persuaded them to pay $200 more than the customer's 1-bike price for 3 bikes. They bought 3, became a "dealer" and still have 2 bikes a year later.

I'm very interested to see if the new cromoly Sun longtail really hits the rumored pricepoint of $550. If so, I'd be tempted to go with it although I am wary of the costs of all the extracycle compatible add-ons.

http://www.sunbicycles.com/product_detail.php?short_code=Atlas+Cargo&cl1=INDUSTRIAL

Disc brakes would appear to be an aftermarket upgrade for the Sun, but the frame is set for them.

 

[Mundo]

I saw this Trek recently at my LBS. it's pretty cool and I am sure it will give Yuba Mundo some competition.

It's a little more money, much lighter, (aluminum frame) better components, fold up and down side shelves.

Trek also makes an E-bike Transport.

http://www.trekbikes.com/us/en/bikes/town/utility/transport

 

[nuevomexicano]

Can someone enlighten me about weight distribution with these cargo bikes? My cargo bike experience is limited to sitting on a Kona Ute in the store and once or twice seeing a kayak-carrying extra cycle kit up close. But I could see myself riding one of these cross country someday.

I noticed that the Trek Transport has cargo racks that extend a fair ways past the back tire and that the cargo bag itself is 3/4 past the rear axle. The other transport bikes I know of (Kona Ute, Xtracycle Radish and Big Dummy, Yuba Mundo) seem to try to balance the load directly over the rear axle and don't have much overhang past the rear tire. I know from loading the various pickups I've owned that its advised to put the heavy load directly over the axle.

Is Trek violating some principle or are they onto something with weight distribution? Is it somehow taking the rider into account? Does it have to do with the rear triangle coming together behind the axle on the Trek and at the axle on bikes like the Yuba Mundo?

 

[amberwolf]

In my experience with my own cargo pods on a regular bike (which are almost completely behind the axle on DayGlo Avenger) and my cargo bike CrazyBike2 which has them about centered on the axle, I'd say handling should be better with them forward of the axle.

Trek probably did it that way to make turning radius and whatnot more typical-bicycle-like, because the longer wheelbase does make a difference in turns, especially under some conditions.

Also note that most pickup trucks seem to have the wheels about halfway along the bed, rather than most or all of the way back, so Trek might be going along some assumptions based on that (shouldn't, since it's 4 wheels vs 2, but...)

Still, I'd rather have the longer wheelbase and keep all the weight between the wheels, instead of behind the rear. My newest bike in progress is intended to be that way, though the cargo rack will still extend out just past the back of the tire, in case I have long or large things or a whole lotta stuff I gotta move at once.

 

[Richard N]

I saw this Trek recently at my LBS. it's pretty cool and I am sure it will give Yuba Mundo some competition.

It's a little more money, much lighter, (aluminum frame) better components, fold up and down side shelves.

Trek also makes an E-bike Transport.

http://www.trekbikes.com/us/en/bikes/town/utility/transport

I've had a good look at that Trek, it's a good looking bike and I'm sure it will sell well, I still think that my preference is for the Yuba, and once I'm familiar with the bike I can always upgrade the components as needed. I think if someone was looking for a peddle only cargo bike and had no intent of going electric that the better components on the Trek would be a better choice. I wonder what the rated capacity of the Trek is, I see on that link that the side racks are rated for 50lbs each.

 

[Richard N]

Something else I've been thinking about is trying to keep a 48 spoke wheel in the rear when doing a rear hub install.

What would be the consequences of having a set of rings machined to fit onto the hub and bolt up to the holes for the spokes, the ring would then have on it's outer diameter holes for a 48 spoke rim.

Would there be a problem with moving the spokes outward in this manner, as in the option A picture below? Or should the rings be machined with a recess on the inside so that the same horizontal plane is maintained, option B?

Option A

Option B

Thanks
Richard

 

[Mundo]

It's too bad 48 hole e-hubs are not avalible....never considered making one, interesting idea.
Since I didn't want to lose the 48 hole hub on the back of my mundo, I used a DD-front hub.
My Mundo is really loaded, I'll attach a picture from Mothers' Day.

I copied this from the Trek Web Site...

The Transport and Transport+ can also support an additional 220lbs of cargo, distributed as 20lbs on the front rack, 100lbs on the rear rack, and 50lbs on each side load rack.
Max combined rider weight of 550lbs:

 

[Richard N]

It's too bad 48 hole e-hubs are not avalible....never considered making one, interesting idea.
Since I didn't want to lose the 48 hole hub on the back of my mundo, I used a DD-front hub.
My Mundo is really loaded, I'll attach a picture from Mothers' Day.

I copied this from the Trek Web Site...

The Transport and Transport+ can also support an additional 220lbs of cargo, distributed as 20lbs on the front rack, 100lbs on the rear rack, and 50lbs on each side load rack.
Max combined rider weight of 550lbs:

I love that photo!

Please tell me about your Mundo, what Hub, what controller and battery, would you change anything? How much range, how fast, how does it climb, what's it like all loaded up? Should I just read your threads instead? :wink:

Thank you
Richard

Edit: Okay I checked your profile and read some info about your bike, still please talk more about it here if you like, I'd love to hear more. It looks like you've changed hubs, also please talk about your trailer too, it looks great.

 

[Mundo]

Okay Richard.

The original hub was from Amped Bikes, it had cheesy steel spokes that were rusting. At the time Amped Bike web site clearly stated, "Heavy Duty Stainless Spokes"! (NOT)
So, during a transition period, I found a deal on a standard 9C, (I think I paid $60 USD for a bare hub, plus shipping), Also, at that time, I contacted Ben at Yuba and got another 48 hole rear hub. I then had both hubs laced into Salsa Gordo wheels/rims with 13 gauge stainless spokes. I think the Amped Bike hub and the 9C Hub are very similar in speed and power.

The controller is a standard Amped Bike controller attached to the outside of a 1430 Pelican Case. Inside the case is a 36 VDC 20 AH Ping Battery.
The battery has held up well, however, I don't ride very far, most of my trips are under 10 miles. I build this bike about 2 years ago and occasionally we go on trips that are 20 plus miles, with no problems.

The bike is top heavy, that being said, if I had it to do over again, I would have had the battery split in two and mounted them under the side racks. At that time, I didn't know Mr. Ping would do that.

Speed, with out the trailer, top speed is around 19/20 MPH on flats, with the trailer, top speed is less, 17 or 18 MPH....On hills, I need to pedal, with or without the trailer.
Additionally, if I had it to do over again, disc brakes would be super. I have seen adapters, so it's still on my wish list.

This bike is not build for speed, it's for pleasure and to take my Son to the park or play ground.


I got the trailer parts from Bob Bell at WIKE, they have a covered wagon on their web site, however, I just purchased fittings, wheels and hoops, then fabricated the rest myself.
For instance, most bike trailers attach to the rear left axel, that wouldn't work on a Mundo. The hitch is in the rear center of the bike.

 

[Richard N]

Thank you Mundo, all good stuff to know. I like your use of the Pelican case for the battery, very clever.

I thought your trailer might have been a Wike but the hitch and ply sides through me, it looks great, and it looks quite sturdy too.

Cheers
Richard

 

[Richard N]

I think I've narrowed my choice down to a hub from CLyte, either the 5304, 5305, or the HT3525. Playing with the simulator over at http://www.ebikes.ca/simulator/ has me scratching my head though. I was hoping that someone here wouldn't mind interpreting these for me.

What I am seeing with these is that the 5304 and the 5305 are giving an almost identical result for thrust on a Ping battery with a 35a controller, with the 5305 being more efficient at the 20mph legal limit, while the 5304 is using far more power compared to the 5305. Looking at the HT3525 it seems to provide more thrust at a higher efficiency and with less power at 20mph, is this correct?

Thank you much
Richard

 

[Richard N]

No responses.

I'm not too surprised I guess, I know that these sort of questions are asked and answered all the time.

 

[Alan B]

The question you probably want to ask first is how much thrust does your planned bike require at your planned speed. Use a bicycle power simulation to determine that first (you may want to do it for level, and your worst case hill, at appropriate speeds for each). Then, for each motor, adjust the throttle to produce that amount of thrust at that speed. Then you can actually compare the results at that speed and see the efficiency, as well as how much throttle is required.

On these wide open throttle graphs you posted, looking at the thrust at 20mph is telling you the maximum thrust it can produce at that speed, and the efficiency and power at that maximum thrust. So you can't tell what the efficiency at the actual thrust you will be using is.