LumanPDX builds a Luna Cycles Fat Cargo Bike

lumenpdx

100 mW
Joined
Oct 23, 2015
Messages
35
Hey! Been lurking around here for years, but last fall the itch really caught and I decided it was finally time to build up my own electric bike. I figure my friends and facebook feed can only put up with so many messy build details, so I'd put all the graphic stuff here. So excited! Where to start...

About Me
I'm an experienced bike mechanic and a fairly strong rider. Cycling is my prefered means of transportation here in Portland, Oregon. I've done a little bit of 3D design and 3D printing, and can usually hack up a piece of metal as needed with enough time and dremel cut-off wheels, but I'm not currently much of a metal fabricator. I hope to improve there. I'm a bit of a tech nerd, I'm a freelance web developer, an experienced computer tech, and an amature electrical engineering hobbyist at best. This will be my first electric bike build.

Build Goals
I don't need electrical help on a bike. My legs are plenty strong, and I enjoy using them. So this bike really needs to do more. It needs go faster, go further, and provide more utility than any conventional bike. It needs to be fun as hell, and look good while doing it. My primary objectives:

Urban transportation. This will be my primary option when I need to get across town quickly and don't feel like grabbing one of my analog bikes. I need to feel comfortable locking it up around town, and it should at least *look* like a bike and not attract too much attention from law enforcement.

Urban hauler. I sold my car, and have no particular love for those boring expensive boxes anyway. So when I need to haul something big or heavy, I need to get creative. This bike should be able to haul a sizeable load in pannier and strapped to the racks, and be up to the task of occasionally pulling several hundred pound trailers up moderate hills.

Festival party bike. Portland's pedalpalooza bike festival is a month of organized bike shinanigans. And each year Burning Man turns the Black Rock Desert into the most bicycle-dense city in the USA. This bike should provide a good platform for some good old fashion artsy burner shit. Strap propane poofers to the racks? Haul a thousand-watt sound system? A trailer-mounted mobile kitchen/bar? A sidecar? So many LED's it sends bystanders into epileptic seizures? Sure, why not!

Nerdy development platform. I want to improve my EE skills, as well as my microcontroller development and C programming skills. This bike should (and already has) provided tons of opportunity to explore. So many ideas...

Electric touring. While not a primary goal, I've done a fair bit of bicycle touring and wonder at the potential of adding some amps to that. I'm not willing to sacrifice any of the other goals to accommodate this, but it's an idea that I can't shrug off.

Technical Goals
After endlessly working my way through reviews, this message board, spec sheets, etc, here are the design goals I gave myself:

Torque and efficient low-speed performance. Pulling trailers and riding at festivals, this bike will likely spend some time pulling heavy loads at low speeds. I need it to do this all day, not just until the drivetrain overheats. This is a primary design goal, and an easy one to fall short on.

Speed. 35mph should do me. That's plenty fast enough on city streets. While I could easily build much faster, I'd rather focus my energy on sustainable torque and amuse myself with the best acceleration I can manage.

Range. The more the better! Adding watt hours to a battery pack has the quadruple benefit of increasing the maximum current output handling, decreasing the average C-rating the batteries see for reduced wear, decreases the average depth of discharge for reduced wear, and, you know, increases your maximum range. So ultimately the bike will get the most battery it can handle (within reason).

Pedaling. Because I like to actually pedal bikes. I want some gears and a drivetrain that doesn't suck. While I don't expect it to be fun, if for some reason I need to work my way home on pedal power alone, this bike should be manageable.

Redundancy. Because I prefer to be prepared and self sufficient, and hate the walk of shame due to bike failure. Also, the party doesn't stop just because one guy's bike isn't cooperating. So anything I can do to assure the bike keeps moving in the face of the unforscene is a good one.

Self contained. As an aspect of self sufficiency, I will have all charging hardware onboard the bike, and will generally ride with an extension cord and tool kit. It will eventually need locking panniers.

Size/Weight. I'm definitely favoring durability and utility over any specific goals. But it should be able to stuff into most places a regular bike can, if needed. Car hatches, truck beds, bus/train bike boxes, etc.

Did I mention it should look awesome? Because it should. Interesting, unique, and attractive. While I love the rolling science experiment as much as the next nerd, and think these e-moto builds are hella hot, what I'm building is a bike for the urban environment. I'll be striving to minimize the number of exposed components, wires, etc, and try to keep the most valuable bits hidden internally.
 
Frame: The Luna Cycles Fat Cargo Bike
I fell in love with this bike the first time I saw it here on ES. It got my imagination racing. The combination of cargo capacity and that built-in battery box sets it apart from most everything else. And those racks? HOLY CRAP. So pretty. So so pretty. I was surprised to learn that they were actually available for sale, and the price for the frame, fork, both racks, both fenders, custom handlebar, and headset is remarkably fair. Aluminum construction and made in the USA. I have some concerns with the detail work and geometry, but I'll follow up on that later.

Motors: Front and rear 8-turn MAC geared hub motors, 135mm axles
These hubs pack a ton of performance into a small package, and should handle low-speed, high torque environments better than most direct drive hubs. Compared to a single rear DD hub like a MXUS, these two motors provide better redundancy, better low-speed characteristics, look a bit more stealth, and came from em3ev who was a joy to work with. I *really* thought I'd be using a BBS02 or BBSHD on this bike build, but in the end decided the increased drivetrain wear and limited opportunity for tweaking/modification was a deal breaker. At the power levels I wanted to put down, a conventional drivetrain starts to blow apart. The MAC is well proven, has been refined over the years, and two of them driven by high-amp controllers should be brutally powerful. I'm hoping to put put about 2500 watts through the rear, and about 2000 through the front. Oil cooling may be explored.
View attachment 2

Controllers: Adaptto Mini-E AWD
I'm slightly concerned about their long-term durability, not entirely comfortable with a self-contained system from a single supplier halfway around the world, and really had to rationalize the price (the single most expensive purchase for the whole build). However it's evident that they provide the most technologically advanced, fully integrated, commercially available e-bike system on the market. The controllers are remarkably powerful for their size, the display is a beautiful dot-matrix, and they're fully configurable without plugging in a programming cable. The integrated BMS is what really put Adaptto over the top for me. That, and as much as appreciate the whole community and ecosystem around the Cycle Analyst, there's no denying that it's just kind of... not pretty. Sure, form follows function, but...
2015-11-24 12.43.14.jpg

Batteries: 8x 4s 16,000mAh Hobbyking Multistar lipo packs. 10c continuous, 20c max, 60 volt @ 32Ah total
I was pretty certain I was going to go with a big 18650 pack. But all the pre-made packs have their own BMS and I wanted to use the Adaptto BMS and charging. Building my own pack would be a fun project, but I've already got enough projects, and I didn't want to add building a battery spot welder to that list. The Adaptto BMS has 4-pin JST balancing connectors built right in, and it turns out 8 of these big lipo packs *just* fit in the Luna's battery box. The price is very reasonable for these packs as well, and if I run into any bad cells down the road it will be easy to unplug and swap out. At 60 volts these MAC motors should really move. With 32Ah of capacity and the Adaptto BMS, I should be able to balance charge them at 4.05 volts, most discharge cycles should be fairly shallow, and hopefully babied like this I'll see a nice long lifespan out of them
2015-11-22 20.28.14.jpg

Onboard Charging: 2x Meanwell HLG-240H-24A
I was super stoked when I found these power supplies. They're compact, weatherproof, and combined put out 480 amps. The Adaptto controller will take anything under the batt voltage as a charging source. Chargers don't usually like to be configured in parallel, so I got two 24 volt units to wire in series. At 48 volts they'll be just under the batt minimum, and the controller won't be as strained as if it was pulling up from a lower voltage. I'll be mounting these in the bike, along with the Adaptto charging coil/capacitor assembly.
View attachment 1

Drivetrain:
Truvativ Hussefelt DH cranks with a 100mm Howitzer bottom bracket. Found a great price, wanted something tough. And black.
DNM 7 speed freehweel. 7 speed is the widest the 135mm MAC can fit, and DNM makes freewheels with wide gear ranges and fast 11t high gears.
Shimano RDFT35 Derailleur. Unsure how this will work. It's designed for compact folding bikes, has a very small cage and an integrated hanger, which is convenient since the Luna doesn't have one built in. Other derailers, along with an add-on hanger, get very expensive quickly.
Shifter: Shimano vintage 8-speed XTR. 7 and 8 speed have the same indexing, and I have some of these old shifters available. Super smooth shifting.

Wheels:
Those MAC hubs, matching front and rear. Origin8 Dat-Pro-80 rims. Sapim Strong 13/14g black spokes with silver brass nipples. Sapim brass spoke head washers. I wanted to be able to fit tires 3-4.5" in size, so wider rims were out. Also, I'm not a fan of the cut-out fat bike rim style. These Origin8's fit the bill perfectly. However because of the alternating drilling pattern, and the narrow hub flange spacing, I ended up using a 1x cross pattern, that also crosses the rim centerline to use the opposite side spoke holes. Without this cross, the spokes will be nearly perpendicular to the axle and provide zero lateral support. Crossing to the opposite side spoke holes should make for a very rigid wheel, but the sharp nipple exit angle and/or kink in the spoke at the nipple head are far from ideal.
2015-12-12 12.33.10.jpg

PHOTOS AND BUILD PROGRESS COMING SOON!!!
 
Welcome to ES. Does the part of Portland you ride in have a lot of hills? if yes, maybe consider a BBS02? you can adjust the amount of assist to very low in order to get a good workout and max possible range from a small and light battery. If the hills are short and mild, another option might be a thin lamination Cute Q100H with a cassette? (rim brake is only option right now)

https://endless-sphere.com/forums/viewtopic.php?f=3&t=72094&start=100#p1125700

edit: OP heavily edited first post with more details, build will now be a wonderful 2WD using 8T MAC's
 
spinningmagnets said:
Welcome to ES. Does the part of Portland you ride in have a lot of hills? if yes, maybe consider a BBS02? you can adjust the amount of assist to very low in order to get a good workout and max possible range from a small and light battery. If the hills are short and mild, another option might be a thin lamination Cute Q100H with a cassette? (rim brake is only option right now)

https://endless-sphere.com/forums/viewtopic.php?f=3&t=72094&start=100#p1125700

You can see in my follow up. I live in a fairly flat part of town, but there's hills all around. The Bafang mid-drives were very seriously considered, but I wanted to put about twice as much power to the wheels as they'd provide. If I didn't want to haul heavy trailers on occasion, it would have been a viable option. I also didn't want to deal with the increased maintenance on the gears/chain/cassette. I very seriously considered going with a BBSHD and a Nuvinci rear end, but they just aren't rated for that much torque, and I'm not convinced that the increased transmission losses of a CVT or IG hub wouldn't eliminate any efficiency gains by a mid drive operating in at a more efficient RPM.

I didn't seriously consider any of the lower power hubs like the Q100H. They seem like nifty little units, but 100lb bike + 210lb rider + 200lb loaded trailer + occasional hills + tiny geared hub motor seemed like a recipe for a bad day. And the goal here is to have really, really good days :mrgreen:
 
Looks like you have a solid plan, well thought out and researched, with proven components to meet your well-defined goals. The bike should turn out very well. I'll be watching. :)
 
Well, I got both wheels built up. I didn't drill the rim holes on the first wheel, and as a result I have a fair bit of kink in some of the spokes at the nipple/spoke junction. Not ideal, and a little disconcerting. On the second wheel I just marked the spoke angle on the holes, then stuck a drill bit through them at an angle. It took off very little material and wasn't as scary a process as I was affraid it might be. Never took a drill to a rim before. But the end results were much better with little or no kink in those spokes. I'm still deciding if it's worth taking the first wheel apart and drilling that one too.

But now the bike stands on it's own! What a beautiful chunk of a bike.

It also has become clear that the Luna can't run both a 4"+ tire and a 7 speed cassette. Not without some serious frame stretching and axle spacing. Though this might be a viable option, I'd prefer to keep the front and rear wheels identical. I don't really need 4" tires for urban riding anyway, so I found some 3" tires. The Duro Beach Bum 26x3" tires fit the 80mm rims perfectly, should roll nice and fast, and look great.

In fairness, Eric at Luna Cycles warned that the bike wasn't really designed for a conventional derailleur and freewheel setup. He's rather adamant that the bike is best with either a mid drive and IG hub, or as a singlespeed. Where would the fun be if I just set mine up like everyone else's?

I think I'll go ahead and fit a spacer and singlespeed freewheel on the front hub. If i want to run some fat off-road tires, I can just swap the wheels when I swap the tires. Not an inconsequential amount of work, but a reasonable tradeoff to get a well-behaving, quick rolling bike on the streets, and a mountain goat on the trails.

Next step: Build the bike up sans-electrics. Get the drivetrain, brakes, and other bits setup so I can take her for a spin. Once that stage is done, I'll be building up the battery and electronics boxes and putting it all together. Stay tuned!

[img=0]2015-12-19 21.38.45.jpg[/img]
 

Attachments

  • 2015-12-19 21.38.45.jpg
    2015-12-19 21.38.45.jpg
    98.6 KB · Views: 1,805
looking forward to this build, my luna frame arrives tomorrow, L/R mid drive soon.

nice find on tires I'll look into them too,
 
Well, with the wheels finally on the Luna, it was time for her to make the way from the living room to the workshop. This project has officially progressed from the collecting-parts stage, to the making-it-happen stage :D

I decided tonight I was going to get the fork and headset taken care of. I like to grease the heck out of my headsets for this NW weather, and had noticed the bottom cup wasn't seated all the way into the frame. Trying to get the fork off was a pain in the ass. For one, the fork attaches both above and below the headtube, complicating attempts to exert coercion. For two, the steerer tube was roughly cut and severely flared. After much pounding and prying, the steerer tube finally came out. I properly pressed the headset cups, inspected and packed the bearings, and got everything back together.

Some notes about the fork and headset:
* Check your headset cups are pressed fully. Mine wasn't when it showed up.
2015-12-20 22.35.36.jpg
* The headset doesn't really have a proper lower shield of any sort, but there is a rubber seal on the bearing unit itself.
* The upper bearings were a sealed unit. The bottom may or may not have been sealed. If it was once a single-piece sealed unit, it wasn't after I got the fork off.
* Even after all the abuse they endured getting the steerer tube out, the headset still spun pretty smooth. It ain't bad.
* The upper face of the lower fork crown appears to have been crudely faced at some point after the frame was painted. There was a lot of rough, bare metal.
2015-12-20 22.35.03.jpg
* The fork is pretty... but it's a chunk. Welds are incomplete, paint missed some spots, and there's vent holes all over upper surfaces. Almost like the factory read the plans upside down or something. This is in contrast to the rest of the frame which seems to be build competently.
2015-12-20 22.34.56.jpg

Also got the bottom bracket installed. The threads were nice and clean, installation was uneventful.

Digging through some old parts, I found a seat post clamp that looks like it was made for the Luna. Score!
file.php


She's going to be heavy. Maybe 100lbs?

file.php
 

Attachments

  • 2015-12-20 23.54.23.jpg
    2015-12-20 23.54.23.jpg
    61.9 KB · Views: 3,243
Good to know. We'll check the headset.

Chalo (helping me with assembly) and I can't get the handlebar to clamp tight enough around the steel steer tube so I ordered an aluminum one. As of now, it just spins if you hold the front wheel in place and turn the handlebars. We are going to try with clamping on the softer aluminum steer tube this week.
 
Mammalian04 said:
Good to know. We'll check the headset.

Chalo (helping me with assembly) and I can't get the handlebar to clamp tight enough around the steel steer tube so I ordered an aluminum one. As of now, it just spins if you hold the front wheel in place and turn the handlebars. We are going to try with clamping on the softer aluminum steer tube this week.

I haven't tried to torque the bars yet, but they felt like they clamped pretty tight. I'm suspecting I'll need to toss the factory bars in a parts bin and throw something else on there, as at 6'1" that cockpit is feeling awfully cramped to me. I think I'm going to need at least another 2-3" from grips to saddle to feel comfortable. As it is now, my only riding position would be sitting straight up.

An aluminum steerer tube would probably have saved a lot of effort, and a fair bit of weight. Where did you find a suitable steerer tube? Or did you just source a straight bit of aluminum tube?
 
lumenpdx said:
Mammalian04 said:
Good to know. We'll check the headset.

Chalo (helping me with assembly) and I can't get the handlebar to clamp tight enough around the steel steer tube so I ordered an aluminum one. As of now, it just spins if you hold the front wheel in place and turn the handlebars. We are going to try with clamping on the softer aluminum steer tube this week.

I haven't tried to torque the bars yet, but they felt like they clamped pretty tight. I'm suspecting I'll need to toss the factory bars in a parts bin and throw something else on there, as at 6'1" that cockpit is feeling awfully cramped to me. I think I'm going to need at least another 2-3" from grips to saddle to feel comfortable. As it is now, my only riding position would be sitting straight up.

An aluminum steerer tube would probably have saved a lot of effort, and a fair bit of weight. Where did you find a suitable steerer tube? Or did you just source a straight bit of aluminum tube?

Just a bit of Aluminum. https://www.amazon.com/gp/aw/d/B000H9JXEI/ref=yo_ii_img?ie=UTF8&psc=1

Good point on using my own bars. I was so focused on getting these to work, I didn't consider using something else. I suspect I might also benefit from a stem as I am 6'2" as well.
 
Mammalian04 said:
Just a bit of Aluminum. https://www.amazon.com/gp/aw/d/B000H9JXEI/ref=yo_ii_img?ie=UTF8&psc=1

Good point on using my own bars. I was so focused on getting these to work, I didn't consider using something else. I suspect I might also benefit from a stem as I am 6'2" as well.

Thanks for the link. I'll probably go ahead and grab that alloy steerer. I ended up throwing a nicely machined Thomson stem on the bike (from my parts bin) and it's precise machining wanted nothing to do with the nasty flared steerer tube. I spent a lot of time hand filing that thing until it would slide on.

At 6'2" I think you'll find the cockpit really cramped. Not unworkable if you plan on leaving the seat low and are happy sitting stright upright, but I couldn't imagine trying to tuck in and get some speed with that configuration. I swapped the bars on mine, I'll post some pics shortly...
 
Got a bunch of work done last night, and she's now technically rideable! Lets see here:

The chainline looks like it's going to work out. But when that derailleur said it has a 28t max for the largest cog, they aren't kidding. I tried pushing it with an 11-30 freewheel, and it just won't lift the chain up onto that biggest ring. I'll need to find an 11-28 freewheel.
2015-12-21 23.34.48.jpg

The rear brake tabs are slotted, suggesting they provide some adjustability in the caliper positioning. But the slots are such that they both extend inward from the bolts, so they don't actually provide any adjustment.

While the handlebar-stem included with the frame is beautiful, it just didn't provide any adjustment and left the bike feeling far too cramped for me. I went ahead and took a Thomson stem I had sitting around, and picked up a new Surly Open Bar. The resulting combo gives me roughly another 2-3" of cockpit space, and narrows the grip by 5-6". Feels great. It looks a little tall though, so I think I'll try flipping the bar.
2015-12-21 23.35.04.jpg

Working on heavy electric bikes is a bitch! My flimsy folding bike work stand is useless with this beast.

I was concerned that the Luna, being a longer bike, would need special derailleur cables and/or longer brake lines. But nope. Everything fit out of the box. I never cut my brake lines down until the bike is *done*, so I'll take care of that later.

ABSOLUTELY EVERYTHING TO DO WITH THAT FORK IS A PAIN IN THE ASS. There isn't a single bolt hole or tab on that fork that didn't require some sort of work. The brake caliper tabs actually had to be drilled out to get bolts through, and they don't appear to be perfectly parallel to the rotor so I'll need to tweak them. Getting the front fender mounted resulted in blood. The 4 fender tabs and fork bosses are a great looking design, but the close tolerances just weren't happening. I ended up mangling one boss, and another appears to have stripped. But the damn thing is on there. And the fender wouldn't' allow the rack to mount without bending its forward extension down a bit. If it wasn't for the fact that it's so damn pretty, and still the best option for this bike, I probably would have shit-canned it.

Eric, if you're reading this.... That fork is rough at best. I'm sure you know that, I'm sure it was selected so you could hit the intended price point. I'm guessing it was sourced from overseas, right? I can't imagine a domestic fabricator turning that out. You know, I bet most of us would happily fork over another $100 (or more maybe?) for a quality fork that matched the frame's build quality.

2015-12-21 23.35.21.jpg
 
The fork was custom made for the bike and that is the problem...it was not made in the thousands....

IF you look at it its made out of steel and has a lot of intricate weldiung to fit the deign of the bike....the rest oi the frame is of course aluminum.

The dropouts on that fork are extra beefy and designed to handle a high wattage hub motor

In the next production run we will get the fork issues worked out.... It is a steep learning curve for the first time you build one that is for sure.

We never had to re drill the brake mounting holes...that might have been a problem specific to your fork.

BUt your right the fork can be a major pain in the asss and its something I will think about how to make it easier.

ERIC
 
Green Machine said:
BUt your right the fork can be a major pain in the asss and its something I will think about how to make it easier.

Yeah, really no worries. Building a small-batch DIY bike kit, I expected to have some rough edges to work out. If the fork had been truly unworkable, I would have shot you an email first to find a solution. As it was, it just took a whole lot of frustrated filing and pounding. I'm not surprised my undersized brake mounting holes isn't common, I suspect each fork has it's own unique, infuriating flaws. In my case I had to ream at least 1-2mm out of those holes (it wasn't just paint). Overall that was nothing compared to getting the fender mounted.

And I know how it is. You can send the best of designs off to a factory, but the smaller the batch, the less fucks they give if you aren't satisfied with the results, even going so far as to act like they're doing you a favor by even taking your order. I'm glad you're aware of this fork's flaws and are already giving thought to the next batch :)

Maybe you can get whoever is doing the frame or racks to take on the fork? I'm sure it will cost more, but this bike already represents such tremendous value, a couple more dollars retail wouldn't be the end of the world.

I'm a little curious about the fork geometry. It appears to have very little rake, making for a very high-trail geometry. Is that intentional? I'm looking forward to seeing how that handles at speed :D
 
ok, I swear I posted an update last night with photos, but today that post is nowhere to be found. Does that happen here on ES?
 
Well, looks like my post from last night disappeared, so I'll post again. I'm going to be deep in a work project for the next week or two, so this might be the last update for a while. But I'm really happy with where the bike is at now.

The Luna still wasn't feeling right. Still a bit cramped and unfamiliar to me, and the overall stance of the bike just wasn't where I'd hoped. So I went ahead and flipped those handlebars, and swapped out the seatpost with one featuring about an inch of kickback. And then BAM! Wow. So much better. Visually the bike has a lower, longer, more aggressive demeanor, and climbing onto her she now feels fast and ready to rock. LOVE IT.
2015-12-22 19.03.48.jpg
2015-12-22 19.03.27.jpg

Also got the headlights installed (though not wired up yet). These cheap units from Amazon are 12-80 volt compatible, and claim 20 watt output, but in my bench testing I never saw them take more than 8-10w. Still, they were dirt cheap, lightweight, seem well constructed, and do throw a good amount of light. Two of them should get the job done nicely. I considered handlebar mounting them but always hate having cables cross the light path, so I mounted them down on the fork/rack bolts. While they'll interfere with mounting front panniers, they don't get in the way of anything strapped to the top of the rack. I think I'll experiment with ways to reduce glare for oncoming vehicles, as none of these lights ever seem to have DOT-style light cut-offs.
2015-12-22 19.15.59.jpg

Got the throttle installed. I'm really digging on the symmetry between the Shimano XTR 8-speed pod on the right side, and the Bafang thumb throttle on the left. Had to file the crap out of the throttle clamp to get it to slide onto the handlebar (must be the paint thickness of the bar that's throwing off the tolerances) but once that was done, no problem.

The chain line seems like it's going to work, but I still have a little tweaking to do. As she sits now, she really doesn't like having the pedals kicked backwards. I think I can tuck in the chainring and narrow the chainline just a hair without problem. I'll give that a try and see if it helps.

When I get a chance to start back in, the next step will be setting up the battery box and fabricating the electronics box. Stay tuned...
 
Back
Top