Agile flatland trail commuter - 1st ebike build project

[LongLostApex]

Commute:
Needs to be able to do roundtrip of 20 miles at about 20mph of mostly flat-ish terrain. My commute is ~90% multi surface trail (asphalt, dirt, gravel moderate level of other bike and pedestrian traffic) and 10% surface city streets. I am 5'11" 170lbs and will be carrying another 15-30 lbs of cargo.

Needs to be able to hold cargo and be maneuverable/agile loaded up. Bike will be left in the garage if it ever rains in California again, but should be water resistant if caught out.

What do I mean by maneuverable/agile? The biggest hazard is transient/homeless encampments that tend to pop up around the underpasses along the trail. Build must be able to reliably stop/swerve/avoid/accelerate from erratically moving foot traffic hazards.

Budget is flexible but ebike is competing with my "fun car" mods budget. Lets say ~$1,500 is my expected starting point.

Initial build thoughts:
fixed steel hybrid frame... possibly a hardtail mtb frame

A "fat-ish" tire to help absorb bumps w/o suspension and handle the multisurface trail. Basically my thought here is to get a wide as wheel as I can get that will mount up to the bottom bracket with a 750w mid-drive

somewhat relaxed/upright riding position

fenders to keep the work clothes as clean as possible

panniers

other attachment points to keep cargo low and balanced

I'm an experienced vehicle modder/tinkerer. However, I haven't ridden or wrenched on a pedal bike in over a decade and have no electric vehicle experience so I'd like my first build to be on the beaten path and be a platform I can adapt/evolve over time.


Initial build components:
This is where I'm looking for some feedback. Current plan: hybrid or hardtail mountainbike frame, "wide as possible" tires that will not require modifying a BBS-02 750w mid-drive, a battery that mounts to the downtube, and disk brakes... No idea about which wheel/tire/brake components yet. Do these make sense for my wants?

What pieces can I commonly expect to find used on craigslist (I live in the bay area so very active craigslist community)?

 

[dogman dan]

Got a welder? You might consider something like this bike I modified.



Thread on the whole build here. https://endless-sphere.com/forums/viewtopic.php?f=6&t=67049

Fairly easy to modify a cheap beach cruiser, lengthening it a foot or less. And the bike is cheap! The result is a much more comfortable ride, with the seat located farther from the rear wheel. You get a rocker, instead of a sharp up and down motion on the saddle. The extra length is not too long, but long enough to give you more saddle bag room, and a nice cargo deck.

Nice comfy upright riding position, and still plenty nimble. Since I added dual disc brakes, its good at a dead stop too. Full fenders and chain guard keeps your shoes pretty dry, and the pants clean. Cruiser tires do well on gravel or dirt, though not as good as a real dirt tire. Plenty of room under the fenders to run a good 2" dirt tire.

For serious cargo hauling, I also added a bob trailer hitch. So it's also a great grocery getter with the trailer added.

I've dorked around with a lot of frames, and by far this is the best e bike I have ever had. I'm running a 1000w motor on it now and it's plenty, but the new controller to upgrade to a powerful 2000w motor is in the mail. This bike will be really fun to ride with double the power leaving a stop sign. 8)

 

[MadRhino]

Needs to be able to hold cargo and be maneuverable/agile loaded up.

AND

somewhat relaxed/upright riding position

Don't go together.

Agile and maneuverable requires a balanced posture, adequate center of gravity and proper geometry. You have to make a choice: 'agile and maneuverable' or 'relaxed upright riding position'.

 

[LongLostApex]

I do have access to a few types of welders, though not in my garage.

That is a good point about agile vs. relaxed.

The more I read, the more I think I should go for a simple but adaptable first build.

revised plan first steps
If I can find a suitable craiglist steel donor bike then that would be best. Otherwise if I get tired of waiting a "big box" store generic steel hybrid frame that has disc brakes that I can re-use is going to be the best entry point to hit my budget I think... then power it with a rear hub motor since that will be one less wheel I have to replace and I don't have much elevation on the commute. If I can find a crraiglist bike with wheels and tires that will work then maybe I can do mid-drive.

 

[dogman dan]

Well, yeah, it's a compromise between max agility, and an upright position. Worth noting that the MTB body position is pretty upright, particularly when compared to a race bike. It's similar to a moto cross motorcycle body position in fact.

You can't just dig a turn all leaned back on the saddle of a cruiser. When you need that turn, you'll want to lean forward, weight the front tire, and get enough front brake on to grab some traction on the front tire, especially in dirt or gravel.

I never said my cruiser was a good single track trail bike. It's not THAT agile. But I certainly can stop good with dual discs, and it's not near as cumbersome to jink around a sleeping bum as this bike was.

My cruiser example just shows you can have a longer bike with decent cargo capacity, without being as gigantic and cumbersome as a Yuba mundo. I carry my battery weight pretty low in the motorcycle bags, and it actually is a very nimble bike for street riding.

If you can live with less cargo ability, find a good quality MTB frame, cheaper used, and make that your commuter. Then even with loaded panniers, its still pretty nimble and has dual mechanical disc brakes. Avoid very cheap aluminum bikes, because their frames are way to bendy for sharp cornering. And even worse, they get more flexy after 6 months of pounding out a commute. Steel and cheap can be ok, but not cheap thin tube aluminum bikes. Get a thick and stiff MTB.

But if you want to load up heavy, it's really hard to beat the very stiff steel cruiser frames, the ones with the extra two bars stiffening the front of the frame. No sideways flex makes em corner nice when really loaded up. On my bike, the welded on rear carrier also adds stiffness to the rear. So it does flick to avoid a pothole or sleeping bum pretty good.

 

[MadRhino]

A cargo bike is always a hard compromise to ride dirt, even on flatland. To make it really agile, you'd need to mod geometry to place the BB and saddle well behind the center of the wheelbase, and the center of gravity close to the middle.

A bike doesn't need to be light weight to handle dirt, as long as it is balanced and the rider can set a proper posture. The problem is to balance a gargo bike, I mean most of them that I've seen are either longtails or front bin. What about a cargo bike with split load.

About this kind of geometry, only a tad bigger, with suspension...
Then you can be agile and safe to handle dirt with cargo.

 

[dogman dan]

Hey, that does look nimble, even loaded like that. I could be wrong, but I thought the dirt trail he was talking about is the graded crusher fine, for joggers type, like some rails to trails routes. So full suspension might not even be needed.

For sure, a full 16" to 24" longer cargo bike is not going to be very nimble. That's why I was thinking along the lines of a bike not much more than 6-9" longer than a typical mtb.

Really, if not too heavy in the panniers, a stock steel beach cruiser is not bad. they are about 3 or 4" longer than an MTB. And loads of room for a large battery in the middle where it belongs. Much of the nimble comes from not fighting frame flex when loaded. Riding in a continuous low speed wobble is not nimble at all. That's why I keep harping on the steel beach cruiser idea.

But any of the really good Dutch commuter cargo bikes have stiff frames. They have nimble cargo bikes figured out for sure. They aren't all long bikes.

On my medium long cruiser, I'm only carrying my battery wrong for looks. It would handle a lot better if I put the battery in the frame of course.

 

[LongLostApex]

I'd never risk sending $2k to China, but as a concept, this caught my eye.

http://www.aliexpress.com/item/HalloMotor-48V-750W-Electric-Bike-X8-Mountain-Ebike-48V-20Ah-Li-ion-Bottom-Discharge-Battery-For/32392507907.html

Anyone seen a DIY version of this?

 

[MadRhino]

I'd never risk sending $2k to China, but as a concept, this caught my eye.

http://www.aliexpress.com/item/HalloMotor-48V-750W-Electric-Bike-X8-Mountain-Ebike-48V-20Ah-Li-ion-Bottom-Discharge-Battery-For/32392507907.html

Anyone seen a DIY version of this?

I don't see much of a problem paying 2K on AliExpress, but I see a big one paying 2K for a stretched wallbike with crap components and low power kit.

For that much, you can have the split load cargo frame in my previous post, made to your size and spec with Titanium tubing. That would be a clever way to spend your 2 K.

 

[slowhands]

When you say commuter, I think of comfort on a regular commute ride. I'd suggest suspension forks and a good suspension seatpost, no matter what. I'd say get 700c wheels too, the ride is smoother. For sure get the fenders and a rack if you think rain and cargo are in the future.

I can generally find a bike or two on craigs list that has the forks and the 700C wheels. You'll have to add the suspension seat and rack in most cases. I've found the Giant Cypress DX or LX to be a good ready made commuter bike, with adequate forks, 700c wheels, suspension seat and a nicely adjustable stem. Here's an example of a converted Giant Cypress, rear hub motor.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=29058&p=418922#p418922

I like the drive trains today, the front and rear derailleurs give you a reliable wide range gear system for all terrain and headwind conditions. With your requirements in mind, I'd suggest front hub motor, and leaving the gears alone. This is the easiest, most reliable and least expensive way to convert to electric. A 48V, 1000w hub motor would serve well. Your battery should suit your intended range, but I'd suggest at least 20Ah so you are not stranded. I'd mount it in the triangle for better weight distribution, not on the rack.

There are lots of other great choices, too. I don't think there's a universal answer. But a simple front hub motor on a comfortable bike will make a great commuter.

 

[LongLostApex]

Well, I picked up a local unloved garage queen for a song.

hardtail 29er with hydraulic disc brakes and plenty of space in the triangle.

Specs:
http://www.rei.com/product/837480/novara-matador-29er-bike-2014


Up next is figuring out what kind of torque arm and rack I can stuff on this:

 

[dogman dan]

No, not a front motor. REAR.

I'd call that an excellent bike choice. God, for a second I was afraid you were going to buy that shit bike. Frame like a drinking straw. Loaded, it would be about as agile as a little red wagon. Whatever style of frame, it all has to begin with a frame that is not cheap and bendy. I think you did good!

Torque arm here, or fabricate your own custom plate to fit the bike and bolt direct to the frame.

http://www.ebikes.ca/shop/ebike-parts/torque-arms/torqarm-v4.html

That frame will love this battery bag. I road tested one for quite some time, it's very good! Battery weight in the frame is of course crucial for keeping it more nimble.

http://em3ev.com/store/index.php?route=product/product&path=35_43&product_id=125

And he does sell a battery to fit the bag perfect as well. 8)

For the rack, a rack that wags is just as bad as a frame that wags. I found Axiom had some stout racks. But most tend to have one weak point, the thin strut that attaches to the frame. You might consider a seatpost rack, then make your own much beefier support struts to attach to the frame to make it super strong, and more importantly, stiff as hell.

Here's a fairly beefy looking axiom rack.

http://www.modernbike.com/axiom-journey-uni-fit-mk-3-rear-rack-aluminum

 

[LongLostApex]

For rear hub motor and controller I'm leaning towards an upgraded Mac kit 500/1000w rear 8 turn and upgraded 12 fet with CA3 and temp sensor with thumb throttle.

Goal is for "good speed" for extended flat land throttle only application. Needs to be a fairly proven and reliable build and a company with a good rep. Any others I should compare?

edit: "8 turn"

 

[Ykick]

12 FET might be a little overkill? Lyen 9 FET is plenty controller to push 30-35A into my 9C DD motor. But, I dunno the Mac setups and maybe a 12 FET is best? I had a generic 12 FET and it was much larger component to mount and accommodate.

 

[dogman dan]

Hard to beat that choice, but as noted, a 12 fet controller might be harder to find a nice place on the bike for it. Really big controllers can take up an entire rear rack top. I never liked the idea of putting controllers on the bottom of the down tube, in all the water spray.

If you really want a similar kit with a much smaller 12 fet 22 amps controller, they are out there.

 

[rider95]

wise someone would make a controller that fits between the fork tubes nice clean air a lot less likely to get muddy

 

[LongLostApex]

Just wanted to update the thread. Ended up just waiting a year to convert my 29er as I still had to take my child to daycare during the workweek. During that year I decided to go BBSHD paired with a 52v 13.5A Pannasonic GA cells in a "Shark pack".

Finishing up my first week commuting today, and am having am absolutely loving it and wanted to update my initial thread. The trail commute is INFINITELY better than being stuck in traffic (especially with no child/carpool lane access), I'm in a much better mood all day long, commute has gone from the worst part of my day to the best!


First week notes:
Have had some issues with the motor loosening up a little every time on the bottom bracket despite me tightening it as tight as physically possible with the Lunacycle wrench. New wrench is on order BPT-1 from Cali ebikes, once it is here I'll use it with a big bar and some blue locktite.

Had a high speed headset wobble that I never noticed previously w/r peddle power, tightened up the headset a smidgen and it went away.

Future plans:
Helmet upgrade - Bell Annex with build in wind visor on order - 30MPH wind with just athletic sunglasses is a bit much for me.

Schwalbe Marathon Plus tires - have passed at least two riders fixing flats every single day on the trail - lots of thorns so need some flat resistance if this is going to be an every day commuter.

Possible brake upgrade from 160mm to 203mm. The stock Tecktro Gemini's are OK, but hauling myself down from 30MPH+ takes some planning at the moment. However looks like my cheap Suntour fork should not run bigger disc's according to the spec sheet. Any other commuters with cheap forks have experience with fork damage under braking?

Picture attached

 

[amberwolf]

Possible brake upgrade from 160mm to 203mm. The stock Tecktro Gemini's are OK, but hauling myself down from 30MPH+ takes some planning at the moment. However looks like my cheap Suntour fork should not run bigger disc's according to the spec sheet. Any other commuters with cheap forks have experience with fork damage under braking?

I use a cheap XCT Suntour fork on SB Cruiser, which is a very heavy trike used to haul even heavier cargo (and dogs) around at 20MPH. I use two sets of clamped-on rim brakes (one on the front side of the fork, one on the rear) for effectively 26" rotor brakes, with no damage so far.

But their moutning points are right up at the thickest part of the fork leg, where it also overlaps with the sliding tube inside it.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&start=475#p1289564