First build, heavy rider, thinking BBSHD, seeking some advice/input

Hey, this is my first post on this forum, though I've been on here several times seeking info.

Hopefully I've chosen to place this in the right subforum.

I've been into EVs for some time, originally from Canada, now live in New Zealand.

I drive an EV Car, and currently have an electric scooter (stand up, kick scooter style). But I finally decided to go all in and switch to a bike (I'm moving further out of the city and will have a longer commute)

First let me qualify by saying, I've got a background as an electronics engineer, so am comfortable around high voltage, current, batteries, soldering, wiring, etc. I've also got a lot of background in RC hobbies, and mechanics, as well as 3D Printing. I've maintained/serviced my own bikes in the past, but haven't owned one in last 3-4 years.

Now for my situation/goals:

• I'm a tall rider, 6'4" tall / 193cm
• I'm a heavy rider, about 300lb / 135kg
• I commute to and from work, and want to avoid traffic/driving, but also avoid arriving a complete sweaty mess
• I want the option to pedal, and put in the effort for exercise as I need it, but also the "easy ride" when I need a "car alternative"
• My commute will be about 5km, + ferry ride (with bike racks) + 5km more each way.
• LOTS of hills. I live in Auckland, 10% - 15% is common all over town, up and down multiple times in only 1-2km, depending on where I'm going, 20% - 25% may be encountered once in a while (though I'm not expecting it to haul my heavy ass up that on throttle alone, and can usually avoid those hills by routing around). The 10% - 15% ones are commonly unavoidable.
• I'm aware that for "street legal" here, it limits to a ridiculous (300Watt) motor limit. But I'm more interested in "play nice, and don't get in trouble". ie: I'm commuting, I drive safe, not in a huge rush, don't care if I can't go over 30km/h, etc... So not concerned about having an over-limit motor. I won't be hot-rodding
• I primarily will be riding on road, may be riding on the odd smooth trail (think parks, etc), no "off-road" or crazy behavior. Mostly just "getting around". If I want to go nuts, I'll build another off-road bike later.
• I have minor lower back issues, and as such an upright riding position may be better.
• Rain is common and unpredictable, so water resistance is a must, waterproof is not (I'm not planning on submerging it, or driving it into the ocean).
• I like to be safe, I'll want good disk brakes, lights front and rear, brake signaling would be nice for added visibility/indication to others, etc
• I have a total budget for the bike of approx $2500 (maybe as high as $3000) NZD for the bike+kit+build

Now, for what I'm thinking:
Based on my research, the most bang for my buck, and recommended drivetrain I'm seeing is a mid-drive, which will give me the hill-climbing torque I'm after for my weight (provided I can gear it well). And the BBSHD seems to be the king in that arena. There is a local distributor in AU/NZ for Luna called Luna-Mate which sells their kit and imports batteries locally, so I'll likely buy from them.

Basically I'm looking at the BBSHD kit, upgraded sprocket, any sensors I might need, DPC-18 display, 48v hard-case battery: http://luna-mate.com/48v-14ah-samsung-35e-nz/ etc.

So based on that, assuming I get the kit, an upgraded sprocket, tool, charger, battery, etc, it all comes out to approx $2000 NZD. Leaving me $500NZD to $1000 NZD for the bike itself to convert, and any upgrades.

On that front, I'm a little torn as to what my best bet is. I don't want to completely cheap out, but I do want to keep a reasonable budget. And I don't need anything fancy. But I want to ensure the basic frame/mechanics will hold up under my weight for normal use.

I'm also not sure about sizing. I know with my height, I'm leaning more towards 29" frames, etc... But for efficiency I might want a smaller wheel (and reduce stress on the drivetrain).

I'm also thinking of this as a workhorse... For getting to and from work, and around. Not in a rush, but I want it to last, and hopefully be easy/affordable to maintain.

I've been tempted to look at IGH options, but then read that the BBSHD tends to tear them up... I could go with a 3 speed, which seem cheap and sturdy, but concerned it won't provide the gear range I need for good climbing and "reasonable but not rushed" speed on flats. While also being usable under leg power when I want to as well... But the ability to change gears stationary, and having a sealed drivetrain is attractive.

A common cassette is cheap and easy to service, etc, but I'm a bit concerned about chain line issues (frame flex due to weight?), and throwing chains... Also maintenance. I'll be taking it on the ferry, it may be exposed to salt water over time, and will likely be prone to corroding like crazy...

That's about as far as I've gotten in my planning, and I decided it's a good idea to pop on here, brain-dump (as I've done above) and ask for some input

Ok... So first off:

• Am I crazy? (the answer to this is yes... Moving on...)
• Does my selection of motor and reasoning there make sense?
• With decent gearing, do you think that motor will haul me up the mentioned hills?
• Can anyone recommend good gearing ratios to start with to achieve the kind of speed/torque requirement I've mentioned?
• For the bike itself, any recommendations? A local vendor with decent selection seems to be https://www.bikebarn.co.nz/ to use for reference for discussion of available models in the local market, pricing, etc
• Recommendations for the sizing of the bike? Impacts? Considerations? etc.
• Any specific gotchas I should be aware of?
• Anything I should know about the BBSHD, it's controller, programming, glitches, etc?

Of course any other input is both welcome, and greatly appreciated.

Thanks in advance for anything anyone can offer!

Looking forward to this build! (I'll start a build thread for it of course). If all goes well on this one, I'll then begin a build for my Wife's ride.

You are on the right track. With lots of steep hills, anything much over 300 pounds of total weight most typical hub motors will be at risk of melting, at least in the hotter months. You are going to be at 360-380 pounds weight. No problem though, for a mid drive. It can gear down to climb those hills, though slowly. A hub can't gear down, so to run a hub you'd need a 2000w system, which would be illegal, and obvious about it.

But the mid drives can do it, on a lot less power, since they can still run at efficient motor rpm, when the wheel rpm is very low.

If you wanted to zip up those hills at 25 kph, then go with a very large hub motor. Essentially a moped like device, rather than bike with assist.

Re the gearing, you just need rear gears on the bike similar to a typical MTB, so 38 tooth on the big rear sprocket, rather than a racing bike cluster with 9 tiny gears. You will have low enough gears as long as its a typical commuter, cruiser, or MTB rear wheel. But not a single gear bike, a 7 speed at least.

Being a big guy, you definitely don't want one of those cheap, teen sized MTB's. Your best bet for a comfortable ride will be a beach cruiser of some kind, but high quality enough to have the right type bottom bracket for the motor. So no on the 150 buck Schwinn or huffy. They have the wrong bottom bracket, look for a square taper crank on the bike. You might still have to make some adjustments for your height, like a longer seat post, and possibly taller handlebars.

bbshd tolerates 1000w continuous

however it can pull 1500w peak

avoid pulling peak more than short bursts



smaller front chain ring better

other than very small wheels

no valid reason to ever use larger than 42t



observe those things

enjoy good drive system

I'd take a long, hard look at the new GNG upgraded Cyclone 3000w. It solves a lot of the Cyclone problems (BB, freewheel, mount and tensioner). If you feed it 52v then it can run at max power without melting very reliably. All the wear parts are common and external (chain/sprockets/freewheel). It's significantly cheaper than the BBSHD, you can achieve an excellent chainline fairly easily and some people have run double front chainrings for climbing (personally I don't think it's necessary)
I'd also see if there are >10 year old downhill bikes for sale in your area. They offer a very relaxed riding position. Usually have excellent components and not a lot of miles. Plus getting heavier springs is easy/cheap.
I'm on my second DH frame build and neither has cost more than a cheap new bike would.

If you can charge at work then battery selection gets significantly easier.

I agree with the used downhill bike comments - as a heavier rider, it is much more comfortable (and safer for roads with unexpected kerbs etc) with full suspension, adjusted to suit your weight.

BBSHD is a good choice as well - my wife has one, I have been so impressed at how it does off road, I am about to build myself one.

Auckland hills haven't been a challenge for one of my bikes, but that is because it is running at about 7000W - so the motor doesn't struggle. I found off road though, after about an hour of very slow, steep uphill riding, the BBSHD will actually perform better than a direct drive.

Actually, another alternative is a geared hub like the Mac 10T - great for commuting, in that you are not manually changing gears all the time. I am not sure of the hill performance vs the BBSHD, but you can have a play on this https://www.ebikes.ca/tools/simulator.html, and see what happens...

Wow, thanks for all the quick replies! Appreciate the feedback!

I'll try to directly address each of your points below (the wonders of multiquote!):

dogman dan said:

You are on the right track. With lots of steep hills, anything much over 300 pounds of total weight most typical hub motors will be at risk of melting, at least in the hotter months. You are going to be at 360-380 pounds weight. No problem though, for a mid drive. It can gear down to climb those hills, though slowly.

Click to expand...

Thanks! Good to hear I'm not off in la-la-land with my thoughts so far. I'm definitely not looking to fly up the hills, if I can maintain 10kph uphill, maybe 15kph with a bit of leg power put in as well, then I'm happy.

dogman dan said:

Re the gearing, you just need rear gears on the bike similar to a typical MTB, so 38 tooth on the big rear sprocket, rather than a racing bike cluster with 9 tiny gears. You will have low enough gears as long as its a typical commuter, cruiser, or MTB rear wheel. But not a single gear bike, a 7 speed at least.

Click to expand...

This is also good to hear. I was waffling back and forth on going with a cassette or an internal geared hub, my main consideratsions were that the cassette (standard derailleur style etc) is easy as it will come on my donor bike most likely, cheap as chips, super easy to maintain/service, etc... But vulnerable to corrosion from environmental issues (daily travel on ferry across salt water). And the need to consciously shift up/down as I'm coming to traffic lights might be irritating, but then again I'll probably get used to it... The internal geared hub is self-contained, sealed, good protection from elements, and in theory lower maintenance. But in reality likely to break due to high torque motor, and if it does, more work/complication to repair/maintain. And is much more costly.

Sounds like from your suggestion, I'm best off going with the "default" derailleur with 7 gears approx, to give me a good range, and if I need to change it later I always can but good to know I won't need to go shopping for a custom cassette of gears. Just use whatever comes on the donor bike.

dogman dan said:

Being a big guy, you definitely don't want one of those cheap, teen sized MTB's. Your best bet for a comfortable ride will be a beach cruiser of some kind, but high quality enough to have the right type bottom bracket for the motor. So no on the 150 buck Schwinn or huffy. They have the wrong bottom bracket, look for a square taper crank on the bike. You might still have to make some adjustments for your height, like a longer seat post, and possibly taller handlebars.

Click to expand...

Yeah, not going with a $199 warehouse special... Thinking $500 is a reasonable amount to spend on the bike itself. But hadn't thought of just replacing the seat post to compensate for the height issue, and taller handlebars to adjust the riding position... That's a good thought. Might have to reserve a bit in the budget for that, but that may make the selection of the bike a bit simpler.

kcuf said:

bbshd tolerates 1000w continuous
however it can pull 1500w peak
avoid pulling peak more than short bursts

Click to expand...

Good to know, for a steep hill climb, assuming I can regulate this by current limiting the controller with different PAS levels, etc... Any good way to monitor draw from the motor with the controller/display on the BBSHD (DPC-18 display)? Anyone have any experience with those? Also is there a good rule of thumb for keeping the motor housing within a safe temperature range? Good way to monitor temperature of the motor? (I mean I could rig up a thermocouple and microcontroller to monitor temps, but doubt I'd be able to rig it into the DPC-18 somehow, so would need secondary display... Maybe bluetooth to my phone? lol... hmm... now my gears are turning... Before I go off and re-invent the wheel, anyone have any easy/simple/reliable temperature or "General Health" monitoring solutions for this type of kit?

kcuf said:

smaller front chain ring better
other than very small wheels
no valid reason to ever use larger than 42t

Click to expand...

I was looking at the 42T Lekkie from Luna, but had some concerns about wear with them being aluminum. Would you suggest going smaller than that? They have a 36T or 28T as well. I know how to calculate speed based on wheel diameter, motor RPM and gear ratios, but unfortunately it's dependent on the torque curve of the motor, and motor RPM output. Any anecdotal experience of speeds with the BBSHD and a specific set of variables, preferably with a heavier rider? (so I can try to reverse calculate and estimate my speeds?). Not trying for fast speeds, if anything trying to figure out how small of a chain ring to go with, to maximize torque of my gearing spread without compromising my top speed much lower than 25-30kph. Ideally if the middle gear was as close to "General purpose" as possible, that would be great for inner-city riding, then I can gear up/down as needed for longer flats or steep hills. to avoid constant shifting.

Grantmac said:

I'd take a long, hard look at the new GNG upgraded Cyclone 3000w. It solves a lot of the Cyclone problems (BB, freewheel, mount and tensioner). If you feed it 52v then it can run at max power without melting very reliably. All the wear parts are common and external (chain/sprockets/freewheel). It's significantly cheaper than the BBSHD, you can achieve an excellent chainline fairly easily and some people have run double front chainrings for climbing (personally I don't think it's necessary)

Click to expand...

Did some quick research on the cyclone. While it offers a bit more power than the BBSHD (looks like cyclone lists peak, BBSHD is nominal, so the gap isn't as huge as it seems). The main concern for me is the BBSHD makes a nice neat self-contained install. Also if I did get stopped for some unfortunate reason (or got into an accident) I'm more likely to explain away the motor labelled 1000W vs one labelled 3000w when the limit is 300w lol... Good recommendation though, it would save me more money to put more into the bike "foundation"... Will re-consider this, and look a bit more into it just to give it more thought. Thanks for the recommendation!

Grantmac said:

I'd also see if there are >10 year old downhill bikes for sale in your area. They offer a very relaxed riding position. Usually have excellent components and not a lot of miles. Plus getting heavier springs is easy/cheap.
I'm on my second DH frame build and neither has cost more than a cheap new bike would.

Click to expand...

This is a good idea. I've looked in the available used market, unfortunately there are only 1 few available at around $1000 to $1200. Then plenty in the $2000 - $5000 range (for used downhill). There are one or two at $500 - $600 but they are damaged in some way, and have no other components (just a frame, no wheels, no gears, no brakes, seat, handlebars, etc...). So that unfortunately sits a bit outside my budget... As I said to your first point, I'll re-consider the Cyclone, which might put this idea within reach. I like the idea of going with something with full suspension, and an over-engineered frame to feel safer. But might need to settle with something in a different class.

Grantmac said:

If you can charge at work then battery selection gets significantly easier.

Click to expand...

I can charge at work, so not as big a deal. But still want decent range between charges if possible. The 48V 14ah Samsung hardcase from Luna looks like a decent battery, easy to remove/service/charge, and install. Fits in a compact space, and is relatively stealthy. (the full triangle packs seem a bit crazy to me lol)

PRW said:

I agree with the used downhill bike comments - as a heavier rider, it is much more comfortable (and safer for roads with unexpected kerbs etc) with full suspension, adjusted to suit your weight.

Click to expand...

Will definitely consider suspension in the frame. And will try to avoid any sudden shocks while riding (knowing that it amplifies stress of my weight on the frame significantly). But as mentioned above, local availability/cost of downhill frames makes it a bit of a budgetary challenge. Can you recommend any specific models available at the bike-barn link I provided that might be similar in capability/suitability? (so that I could use them in keyword searches in the local used market...) Or if they are cheap enough, buy one new?

PRW said:

BBSHD is a good choice as well - my wife has one, I have been so impressed at how it does off road, I am about to build myself one.

Click to expand...

Awesome! Good to know, thanks for the re-assurance on that motor selection!

PRW said:

Auckland hills haven't been a challenge for one of my bikes, but that is because it is running at about 7000W - so the motor doesn't struggle. I found off road though, after about an hour of very slow, steep uphill riding, the BBSHD will actually perform better than a direct drive.

Click to expand...

Lol, 7000W yeah I'd like to hope it doesn't struggle lol...

Again good to hear again my choice of going mid-drive and BBSHD seems to be "sane".

I see from your profile you're also in Auckland, any other advice you could offer? While I currently live in the CBD (near the top of nelson at the pink path) I'll soon be moving north, and taking the ferry into the CBD, then getting around the City on the bike (I go back and forth between the AirNZ office (Wynyard Quarter) and Grafton for example). so lots of elevation change. Also hit other spots around the CBD as well. Any specific routes you know of that are good?

PRW said:

Actually, another alternative is a geared hub like the Mac 10T - great for commuting, in that you are not manually changing gears all the time. I am not sure of the hill performance vs the BBSHD, but you can have a play on this https://www.ebikes.ca/tools/simulator.html, and see what happens...

Click to expand...

Interesting! I'll take a look at that simulator for sure, and see what I can learn. Does the geared hub motor have different gears? or is it just a gear reduced hub motor with a fixed gear ratio to add a more favorable torque curve?

Thanks again everyone for your feedback, this is a great discussion, and it's helping to drive my thinking so I can nail down the remaining details.

Hoping to begin my build in about a month or so, for now just finalising plans/details so that I can try to optimize what I get on my first go... Realizing of course that I'll probably end up with a "V2" at some time in the future, once I've jumped in with both feed, and know more what I need. Trying to reduce the "newbie mistakes" through research

https://gngebike.com/mid-drive-kits
https://www.gngebike.com/gng-2019-3000w
Looks interesting, the BB brackets now slide, and the bottom plate of the bb brackets is suited for the BB length. No bend in the bb bracket.

Grantmac said:

I'd take a long, hard look at the new GNG upgraded Cyclone 3000w. It solves a lot of the Cyclone problems (BB, freewheel, mount and tensioner).

Click to expand...

Glasswalker,
some more reading … bikes that fit BBSHDs https://electricbike.com/forum/forum/builds/ebike-building-directions/7635-bikes-that-are-compatible-with-a-bbshd-and-bbso2-kits/page1
and geared motors vs direct... http://www.ebikeschool.com/geared-hub-motors-vs-gearless-hub-motors/

I will have a look at Trade Me and your bike-barn link when I have some time. Note that the BBSHD comes in different width, to suit the different bottom bracket width...

In my opinion, a downhill bike (or any full suspension MTB) makes a crap commuter, because you quickly run out of places for your stuff. It's hard enough just to fit a decent battery on one of those toy bikes. If you are going to remain within the legal-ish speed range, there's no case to be made for it. It would be more versatile and useful, to say nothing of stealthy and low-key, to use a touring-oriented bike like the Surly Troll rather than some boingy poser bike. If you use a cargo bike like the Surly Big Dummy or Soma Pick-Up Artist, you might find it to be a better car replacement than even the most versatile normal bike would be.

Even if you use a 26"rear wheel, using a Shimano 29er rated hub is a good idea, because it's intended for larger gear reductions than usual.

Based on my experience of the BBS02, I think a bike with 26" rear wheel, 11-40 cassette, and 42t front sprocket would be workable for the BBSHD in your application. The advantage to the stock 42t ring is that it's made from steel, and has the potential to last much longer than the aluminum aftermarket rings. You can always resort to them if you find you don't have low enough gearing for the job.

depending on programming

lower pas levels limit

peak power levels

display with power meter

can help visually



depends on bike

in general

much smaller than 40t

little if any offset

results poor chain line




important thing regarding

1000 1500w pulling chain

never run worn chain

any signs of chain wear stretch

replace thus save sprockets



good luck