Looking for guidance building a bike for commuting

[Capsloast]

Desired Max Speed: 20 MPH (32kph) throttle only
Desired Range @ 15-20MPH: 20m (32km) at least, the more the better
Terrain: Mostly new good quality roads, some pothole ridden old roads and rough dirt/grass (some of the areas near me are undeveloped). Mostly flat, max hill grade ~9%, average of 0%-3%
Brake type of motor wheel: Would prefer a disc brake as I expect to occasionally have to ride in rain
Preferred Wheel Size: No real preference
Rider weight: 150 lbs
Location: North Texas, USA

My budget is $1300. This will be my primary mode of transportation, I don't have a car so it really needs to be reliable.

I don't own a bike I can use as a donor and I'm looking to buy new. Craigslist hasn't turned up anything suitable for my height (5'5" (165cm) with a 29" (73.66cm) inseam). Might be able to find something used at a local bike shop but I haven't yet checked and I'm not at all confident I could spot a good deal as I haven't ridden a bike in a long time and even then I was not an enthusiast or cycler.

The bike I've been considering is a 2019 Trek 820 ($400)
Pros and Cons:
+ Steel Frame
+ Front Suspension (mainly for comfort on rougher terrain, not planning on doing any actual mountainbiking)
+ Rear hub appears to be 135mm, allowing me to fit a hub motor without bending the frame (assuming ebay seller dimensions are accurate)
- No disc brakes or frame mounts to add them

The motor and battery I am looking at getting:

48v 1000w 26" rear hub kit from Ebay (haven't chosen one yet, don't really know if theres any difference) ($160~)
48v Shark GA 13.5ah + 48v Advanced Luna 300W Ebike Charger ($540 + $70 shipping)

With a set of torque arms this setup puts me at around $1250~ including tax and shipping, hopefully giving me some room to buy a set of fenders.

I'm open to suggestions on any part of this build, I haven't purchased anything yet. My budget is pretty fixed though and I can't really afford to go over it.


Main questions and concerns:

1) Does it even make sense from a value standpoint to build a bike like this? I understand doing it if you want a more powerful bike, or if you have a used bike you can convert to save money, but I am most likely going to end up buying everything new and I just want to get around the city without being drenched in sweat on a bike that isn't going to break. My biggest issue with purpose built bikes is they are almost all designed for people 5'7" and up with the only option for shorter people being to get some hideous stepthrough to make it a little bit easier to get on a bike that is basically still too big. Most of the ones in my price range are only sold online so I have no way of testing them. Putting together one myself with a new bike seemed like the best approach, but it really only helps if I end up with a working bike by the end.

2) I really don't want my wiring to melt or my battery to catch fire, is there anything I need to know from a safety standpoint other than making sure I buy the right motor wind and a battery from a reputable vendor?

3) Speaking of motor wind... is there any way to tell what the motor wind is on those cheap ebay kits?

4) Are shark battery cradles standardized such that you can use any shark battery in them? I figure I could unplug my battery and take it with me after locking up my bike. That way if it gets stolen at least I still have the battery, I just don't know if I could replace the cradle that attaches to the bike. Most battery sellers dont seem to sell replacement cradles. Golden Motor sells one but doesn't list compatibility.

5) Is it worth getting an advanced charger? My primary concern is safety, not battery longevity and I could save $50 without it.

6) Am I right in assuming most of these hub motors on ebay are pretty much the same? They all look identical, some of them have copy pasted descriptions from each other.

7) How does my current plan (Trek 820, ebay rear hub motor, Luna battery/charger) look for meeting my needs? Any suggestions on what I could improve? Things I may have overlooked or forgotten?



Any insight would be appreciated, thanks for reading.

 

[motomech]

Craigslist hasn't turned up anything suitable for my height (5'5" (165cm) with a 29" (73.66cm) inseam).

Are you by chance a female? I've known some girls who are "all legs"(works well), but on a guy, I'm thinking these measurements would be rather strange.

 

[Capsloast]

Are you by chance a female? I've known some girls who are "all legs"(works well), but on a guy, I'm thinking these measurements would be rather strange.

Nah sadly I'm just a short guy. Were you expecting the inseam to be more or less? Because bike sizing charts are absolutely baffling to me; Example: 29.5" inseam at 5 feet tall? Am I just all torso or what?

Just as an additional addendum to my original post:

I noticed Lunacycle currently has a TSDZ2 750w mid drive kit on sale, including the battery.

This would bring me to $1375ish with the 820. Over my limit but I think I could swing it if it's a good value instead of a hub. I just have no idea what the bracket size is on the 820.

 

[markz]

You will do well with a Leaf kit, from leafbike or leafmotor, get the 1500W rear wheel kit with the KT display, your speeds would work well with a 36V system. Buy some torque arms from www.ebikes.ca, buy a spare throttle, thumb throttles are what I like. I buy mine from Greentime on Aliexpress (LINK) as for a battery purchase can only suggest reputable sellers so www.ebikes.ca, www.em3ev.com, Unit Pack Power is another good one. Battery is the most expensive part. For the Motor Turn, since you are going fast, a 5T motor would be good, nice balance of speed and "torque" not that different turn motors have more or less torque, they have the exact same, but its all a balancing act like a teeter totter. Do not give into the SPEED vs TORQUE MYTH that some sellers still propagate. A 3T motor just means you get more rpm/volt it has shorter and thicker strands of motor wire which means you can dump a shitton on amps into it for longer, then a 8T motor with thinner and longer strands of motor wire. 5T or 6T is good for you.

Mid Drives will be a bit noisy, they are ideal for hilly terrain.
Direct Drive is simple, less moving parts, and is much more silent then a geared motor or mid drive.

Its only a matter of how long those steep terrain sections are. I will slap up some Google Maps links for you to see what a direct drive motor can handle.

Easy https://www.google.com/maps/@50.9307774,-114.1155345,3a,75y,320.05h,80.92t/data=!3m5!1e1!3m3!1sPwYqBVd0jcj00wlbRxjfbw!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DPwYqBVd0jcj00wlbRxjfbw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D132.32755%26pitch%3D0%26thumbfov%3D100

https://www.google.com/maps/@50.9310245,-114.0326786,3a,75y,256.14h,75.67t/data=!3m7!1e1!3m5!1sXYWR9r0f1Gl-rQ16i06KSw!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DXYWR9r0f1Gl-rQ16i06KSw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D120.31642%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

https://www.google.com/maps/@50.9317542,-114.0273375,3a,75y,96.79h,90t/data=!3m7!1e1!3m5!1s2ITr4lK9-im7lJwayGL1Tw!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3D2ITr4lK9-im7lJwayGL1Tw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D100.69279%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

https://www.google.com/maps/@50.9871516,-114.0444167,3a,75y,258.71h,86.96t/data=!3m7!1e1!3m5!1snJDYIlSfuFEvh2-ZXmJ-_A!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DnJDYIlSfuFEvh2-ZXmJ-_A%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D316.74387%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

 

[Capsloast]

Thanks you for the insight

You will do well with a Leaf kit, from leafbike or leafmotor, get the 1500W rear wheel kit with the KT display, your speeds would work well with a 36V system.

Could you elaborate what you mean by a 36v system? Looking at leafbikes offerings I don't see a 36v 1500w kit

Their wheel builds also don't appear to come with a casette, will I be able to just reuse the casette that comes with the 820? (It's a Shimano TZ21, 14-28, 7 speed)

Easy https://www.google.com/maps/@50.9307774,-114.1155345,3a,75y,320.05h,80.92t/data=!3m5!1e1!3m3!1sPwYqBVd0jcj00wlbRxjfbw!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DPwYqBVd0jcj00wlbRxjfbw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D132.32755%26pitch%3D0%26thumbfov%3D100

https://www.google.com/maps/@50.9310245,-114.0326786,3a,75y,256.14h,75.67t/data=!3m7!1e1!3m5!1sXYWR9r0f1Gl-rQ16i06KSw!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DXYWR9r0f1Gl-rQ16i06KSw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D120.31642%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

https://www.google.com/maps/@50.9317542,-114.0273375,3a,75y,96.79h,90t/data=!3m7!1e1!3m5!1s2ITr4lK9-im7lJwayGL1Tw!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3D2ITr4lK9-im7lJwayGL1Tw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D100.69279%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

https://www.google.com/maps/@50.9871516,-114.0444167,3a,75y,258.71h,86.96t/data=!3m7!1e1!3m5!1snJDYIlSfuFEvh2-ZXmJ-_A!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DnJDYIlSfuFEvh2-ZXmJ-_A%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D316.74387%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

Definitely looks good enough for my area, our inclines aren't very long

 

[markz]

.

The motors usually use a freewheel, a few motors, like from BMS Battery, have cassette's you can use. You install them to what you want. I personally do not use gears, I haven't had a chain on my bike for a year now others have stated they use very little of their gears, so a 5 speed in the rear is plenty! No more then 7 speeds thats for sure!

You can use any voltage you want with any motor, voltage defines speed, also defines your battery and your low voltage cut off so you do not damage your battery pack.

You are wanting a throttle only, no pedal assist, you have a few hills at 9% but do not indicate how long those slopes are.

You can have a look at BMS Battery, people have bought from them, mixed reactions but nothing too too bad from https://bmsbattery.com/20-motor - you will see how they laid out there motors by voltage, ignore that. They have small geared hubs for people who love to break a sweat and actually pedal the Bafang CST looks to be a cassette motor, but it really does not matter unless you want specifics, but you are throttle only right. Their Q11 is the generic direct drive, probably 1000W.

You could also go with Luna, I must've missed that part as I loosely skimmed over, their batteries seem to be solid, reputable with very little fall out, probably only around rush time, say Christmas things seem to fall through the cracks like any business.

Again no need for you to have a mid drive motor, non. Unless you are in stop and go traffic, say in the downtown core. Also mid drive are for lots of hills, up down up down, and long hills, and very steep hills. If you insist, Cyclone TW has mid drives, very stout, very nice. I have their 3000W which can handle 450lbs up 20% grade for 150 meters. The Bafang is very slick and nice mid drive, lots of people love it for its sleek looks, its ease of installation, less fussing around.

I believe these are direct drive, easier, simpler, no noise, as mentioned.
https://lunacycle.com/golden-pie-v5-golden-motor-hub-kit/
Do a google search, downside is "Built in sine wave controller" which is not good for heat buildup, so I wouldnt recommend that motor. Mac motor is a good quality geared motor, can handle lots of power, but its noisy with the gears, more moving parts means more can go wrong.

I tell you, for the value of the https://www.leafbike.com/ you cant go wrong!
Tack on an extra hunny for s/h and you just need a battery!
The 1000W is the same size and weight as the 1500W, so might as well just go ahead and buy the 1500W rear Leafbike kit. Probably not the best lace job around, maybe wise to buy a decent quality rim from your local bike store, find a source for custom cut spokes and have fun on Youtube, its quite easy to lace a motor into a wheel. Just takes time and patience.

www.ebikes.ca can see you custom cut spokes
https://www.ebikes.ca/tools/spoke-calc.html

Another way to go, is just buy everything from ebikes.ca in Vancouver Canada.
Buy your motor, get them to lace it for you, buy your controller there, and battery there as well.
One Stop Shop!
Its expensive, but the back end support for their customers is top notch.

 

[lionman]

48v 13.5Ah might not get you 32km range throttle only. If you manage to eek out that much from it you will be discharging the pack very deeply which will reduce its cycle life considerably. I would aim for a bigger pack personally, don't discharge it so deeply and get more years of use out of it.

Maybe look at a EM3EV triangle. You can get a 52v 22Ah for 500USD plus delivery.
https://em3ev.com/shop/50v-14s9p-large-triangle-pack/?currency=USD

If you really want one in a case their jumbo shark comes in a 52v 17Ah variant for 480USD plus shipping.
https://em3ev.com/shop/em3ev-52v-14s5p-jumbo-shark-ebike-battery/?currency=USD

I recently built a bike using a Trek Marlin 5 2018, 1500w direct drive kit and a 52v 24Ah battery. I am a bit heavier than you but I don't get much more than 30km from mine without discharging the pack more deeply than I would like to regularly do.

 

[ScooterMan101]

Performance Bike is going out of business, check the local one to you for a bike.
Nashbar is their sister company and often have good deals.
There are small , 15 inch frames that are perfect for you.

You will want a bike that has 7 or 8 speeds as that is usually the largest rear freewheel you can screw onto a cheep hub motor and still have clearance for the chain to not rub the frame while in the smallest cog.
( Some motors are now being built that will accept 9 and 10 speed freewheels or cassettes )
Front suspension ( the cheap ones are good enough for road riding, just do not take it to the Mountains )
You will want disc brakes when riding over 15 mph.
Get a suspension seatpost.
Remember about the wind chill factor, so have good gloves , etc. available to wear.

 

[Capsloast]

You are wanting a throttle only, no pedal assist, you have a few hills at 9% but do not indicate how long those slopes are.

...

A few examples: 6% grade for a quarter mile. Here's an example of a road with some rolling hills here, lots of up and down the whole way through, average grade of 4-5% but each hill is a quarter mile or less. A longer hill, roughly 3% grade but not the whole way through, flattens out in the middle. (btw these are hill grade estimates I got from veloroutes hillgrade calculator, I am just assuming it's correct)

Tbh I just rolled it up to 9% because I figured that'd give me a little extra room if I underestimated it, I don't know the area *super* well yet because of my lack of transportation heh

These are the best examples I could think of and I think they're pretty typical of where I am in Texas, they aren't steep and I don't expect to be doing long climbs. Maybe an occasional long 1-2 mile stretch of 1-2% at worst. I take it that it's probably not worth getting a high torque motor for terrain like this?

48v 13.5Ah might not get you 32km range throttle only. If you manage to eek out that much from it you will be discharging the pack very deeply which will reduce its cycle life considerably. I would aim for a bigger pack personally, don't discharge it so deeply and get more years of use out of it....

I was notified that triangle battery is out of stock when I attempted to add it to my cart I also need a charger, so I have to factor that into the cost which adds another $30 from em3ev.

Anyway I guess I'll have to lower my expectations for what kind of range I can get on my budget. Do you think I'd be able to hit the 20 mile marker comfortably with a 48v/13.5ah battery by pedaling 25-50% of the time and going at a lower speed (preferably over 10 mph at least)? My budget is a lot less flexible than my willingness to pedal or go at slower speeds. I don't plan on doing 20 mile rides every day, that's just the max that I need to be able to go every once in a while. I don't mind having to buy a new battery in a year or so if that's what it's going to take.

Performance Bike is going out of business, check the local one to you for a bike.
Nashbar is their sister company and often have good deals.
There are small , 15 inch frames that are perfect for you.

Thanks for the headsup! There's one near me, I'll try to head there this week and see what they've got, also thanks for the explanation of what I should be looking for. I was planning to get a suspension seatpost eventually, though I was concerned as to whether or not there would be enough distance between the seat and the frame for a long travel one on a small bike frame. Suppose I'll find out.

Is it worth it at all focusing on getting a steel frame bike? My biggest fear is that I'm going to end up with an aluminum frame and a hub that doesn't fit it and not being able to bend the frame to get it in. Maybe I'm making this a bigger deal than it is though.

I'll be sure to get some gloves

 

[docw009]

Tough to build one for cheaper than a Chinese import.
https://www.amazon.com/ECOTRIC-Electric-Mountain-Assembled-Packaging/dp/B07FYFHBBF/ref=pd_sbs_468_2?_encoding=UTF8&pd_rd_i=B07FYFHBBF&pd_rd_r=f28ff6d4-2f54-11e9-b078-d9bf83a301a9&pd_rd_w=FAT1e&pd_rd_wg=fp7hK&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=KE3R6Q3NK79A49WHXSZ4&refRID=KE3R6Q3NK79A49WHXSZ4

 

[E-HP]

Tough to build one for cheaper than a Chinese import.
https://www.amazon.com/ECOTRIC-Electric-Mountain-Assembled-Packaging/dp/B07FYFHBBF/ref=pd_sbs_468_2?_encoding=UTF8&pd_rd_i=B07FYFHBBF&pd_rd_r=f28ff6d4-2f54-11e9-b078-d9bf83a301a9&pd_rd_w=FAT1e&pd_rd_wg=fp7hK&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=KE3R6Q3NK79A49WHXSZ4&refRID=KE3R6Q3NK79A49WHXSZ4

And there are tons of suspension forks on Craigslist.
Or, there's the front suspension version, with slightly higher mileage claim for $80 more:
https://www.amazon.com/Merax-Aluminum-Electric-Mountain-Shimano/dp/B074Z8C7SQ/ref=sr_1_53?keywords=bicycle&qid=1550040814&s=gateway&sr=8-53
no fenders, but you get a headlight...

 

[dogman dan]

You are on the right track in general. E bike commute can be a money saver, but if you are still licensed, a smaller motorcycle can be much cheaper per mile. I personally made e bike commuting pay, getting rid of $20,000 in charge card debt, by avoiding replacing the car for four years. Barely driving the car, I made that wore out turd last long enough to pay out that debt.


But I am not joking about a gas scooter or motorcycle. My ebikes have all cost about 30-50 cents a mile, but a $2000 used motorcycle can cost as little as 12 cents a mile, and certainly no more than 20 cents. However, you WILL go a lot more miles on that motorcycle than the bike, so total cost per year of an ebike can be lower.


The trek 820, or any similar type bike such as a giant or specialized will have all you need for commuting. Steel frame might not have disk brakes, but disk mounts can be fairly easily added to a steel frame. Other similar bikes but a bit more expensive tend to come with disk these days. Disk only on the front is easy, just a fork change away. Rim brakes do still work in the rain, and in general, you do want to ride different in the wet anyway, not using brakes much, relying on coasting down to all stops. Your motor will help do some of that, every time you get off the throttle. It will resist enough to slow quicker than usual for bikes. Whatever you get, you can always upgrade to disk later, if it has the mounts, or is a steel bike. ( you can weld shit onto a steel frame)

BEFORE you pop on a new bike, take a look around for a similar quality bike used, for $100 or less. Those steel frames don't wear out. Fixed up for another hundred with new tires and anything else like a better saddle, you get the same bike for $200. Hell, I picked a Giant Rincon out of the dumpster pile on the curb once. Its one of my better street/dirt bikes. I just recently got a fantastic road bike for 30 bucks at an estate sale. Worth about $400. Have a look first is all I'm saying.


Do avoid picking up a used bike that was junk to begin with. The cheapest mtb's at Walmart are junk, fit adults poorly, and can last less than a year in heavy use. Bottom of the line trek, specialized, giant are decent bikes that fit adults.

Don't rule out a cheap steel beach cruiser though. As long as it has two rim brakes and a 7 speed rear gear, they can make really great commuters. Very sturdy, and more important, much more comfortable on long rides than MTB's. And new, as low as $150. Schwinns, Huffies. The best beach cruiser is the Electra townie. ( around $500)


A cheap motor kit will come with a decent, hugely durable motor. But they do cheap out on the controllers and the wiring. All fixable, and if it comes not functional, the vendor should send you new controller. But for your first bike, on a tight budget, nothing wrong with the cheaper kits. But one thing, get it from the US. A china supplier will be harder to get replacement shit from. Worth the extra 50 or so, if you need warranty parts. After the warranty of about a day after you get it, you can still get controllers and throttles from ebay, cheap.


Battery safety. I have run the most dangerous type battery for almost a decade now with zero problems. I treat it like its explosive. I kept them in a fireplace in the house, and now after the house remodel removed the fireplace, I have an outdoor battery bunker made from the old kitchen stove.


That remodel,, well, I had other , "Safe " batteries too. One of them burned down my garage, and smoked the house. This is very rare shit really, but it did happen to me, because I trusted that thing inside while it was charging. My advise now is battery bunker outside, or at least in a garage not attached to the house.


Chances are you go a lifetime with no battery fires. They really are rare. But if it does happen, you get a big ass fire. So just don't bring that thing in your house.

 

[markz]

For $600 for an ebike off of Amazon, sounds sketchy asfuck! The bike is worse then a Walmart bicycle aka Bicycle Shaped Object, and the battery.... gosh knows what bottom of the barrel batteries they put in there. Find a used brand name bicycle from the online classifieds, Craigslist, Kijiji, eBay, or Pinkbike, even an el cheapo would be $100, say an old circa 1990's GT and build from that.

$400 48V 15Ah 720Wh / 14Wh per mile is 51miles https://www.leafbike.com/products/lithium-battery/48v-li-battery/48v-15ah-rack-lithium-ion-battery-1000.html

$343
https://www.leafbike.com/products/diy-bike-conversion-kit/26-inch-electric-hub-motor-kit/26-inch-48v-1500w-rear-hub-motor-bike-conversion-kit-987.html

Spare Throttle - https://www.leafbike.com/products/electric-bike-parts/throttle/c-47/
Torque Arms - https://www.leafbike.com/products/electric-bike-parts/torque-arm/c-112/
Freewheel Removal Tool, Puller, Spoke Wrench - https://www.leafbike.com/products/electric-bike-parts/bike-tools/c-114/


Bicycle - https://www.pinkbike.com/buysell/2387430/
Matching ebike kit - https://www.leafbike.com/products/diy-bike-conversion-kit/275-inch-electric-hub-motor-kit/275-inch-48v-1500w-rear-hub-motor-650b-bike-conversion-kit-1068.html

 

[lionman]

Their small hard cased triangles are in stock.

https://em3ev.com/shop/50v-14s6p-small-triangle-pack/

18.6Ah for $449
20.4Ah for $569

These have smart BMS which you can configure and monitor via bluetooth and come with a frame bag for mounting.

One of those, along with cheap direct drive hub motor from ebay and second hand brand name donor bike is the way to go. Get in there under 1K probably.

Done skimp on battery and charger. These are the most important parts.