Seeking advice on first build for my wife.

[lebnjay]

Hello all, hoping to get some advice.
I am new to all this but have been reading here to try to figure things out.
My wife would like an electric assist and I'm trying to decide on the best way to proceed.
She has an early 90's trek step through chromoly steel ridgid frame mountain bike that we are fixing up to use as a commuter, grocery getter, and kid hauler.
She doesn't need to go fast, I think 20mph would be plenty, and our rides won't be very long, 20-25 miles would probably be the max.
We will be riding mostly on flat ground in Bend, OR with some minor hills, and we live up a bit of a hill about 10% grade for about 1,000ft.
Sometimes she will be pulling our young daughter in a bike trailer, sometimes with groceries as well.
We also plan on adding a front box cargo attatchment that replaces the front wheel, The Lift, currently on Kickstarter, that she will be pushing sometimes when I am not.
She would love it if the bike stayed pretty light and quiet and didn't feel much different than it does now, just was a little easier to ride, less work on the hills and a little quicker, especially with the extra weight. She would like to still pedal, and likely just use pas.
She is also not a super strong rider and generally feels a little uncomfortable getting started at stop signs, especially with the extra weight, so something that would smooth out that initial acceleration would be great.
We are also trying to keep this fairly low cost, money is a little tighter now with the little one.
Down the line I would like to build up a bit more powerful system for myself for pushing the cargo bike further and faster with more weight on my bike.

Based on what I have read here I am leaning towards a geared rear hub, but there are so many to choose from. I would like something that can handle the torque of some hills and extra weight, as well as assisting from a dead stop, and has a good pedal assist system. Something that is very low maintenance and dependable, and ideally the kit can be well under $1000.

What do you guys think?
I am drawn towards bmsbattery's torque imitation controllers, would a q128c be a good option?
maybe a Mac geared hub
There are so many vendors, and shipping seems crazy high if it is coming from overseas.
Lunacycle mightymini 52v pack seems like it could be a good way to go for battery.

Any advice would be much appreciated, let me know if any more details would be helpful
Lebn

 

[Rassy]

I am now biased towards a crank drive, such as the BBS02. You didn't put it on your list, but IMO your requirements all shout out to the very thing a crank drive is good for. Light weight, can still pedal without assist when you wish, handles the extra load and moderate to steep hills without issues.

Also, much easier to install than a rear hub motor.

Whatever you choose to do, good luck with the conversion.

Edit: Oh yes, welcome to the forum.

 

[e-beach]

Hey lebnjay! Welcome to ES.

After reading your post it occurred to me that your wife must be strong. If she is going to be pedeling the Lift up the 10% grade she has to be strong.

Here is the thing. Weight and distance on an ebike means you will need to burn watts. Add speed to he mix and you will be burning more. For an average ebike builder 20-25 miles could be had from a 36v setup with a 15ah battery if you pedal all the time. But if you add a lot of extra weight then you need either more battery or more voltage. Either way you are adding more battery's which equals more cost and weight. So you need to find the balance for your needs.

A 48v 20ah 1000w DD or geared hub motor on the rear wheel would probably work. Might even get you farther then 25 miles if you use the pedal assist. I roll around on a yescomusa.com DD that has been very robust and dependable. My bike and battery are about 80lbs. Expect a 48v 20ah bike to be heaver. Be sure to maintain the electronics and battery so your wife isn't pedaling a heavy bike a long distance with kids.

Take a look at what Grin has to offer. http://www.ebikes.ca/. They are probably the best in the business for kits.
Also people like paul at http://em3ev.com/store/

Anyway, Welcome to ES

 

[lebnjay]

Thank you for the welcome and for the replies.
My wife is not a particularly strong rider, hence the desire for the electric assist kit, especially for that last short hill getting home. She can pull the trailer up, albeit slowly and in the granny gear, but maybe wouldn't be able to push the front cargo attachment up.
I had considered the mid-drive kits, and still think that's the way I would like to go for my bike down the road if it works. The problem is the cargo attachment attaches at the bottom bracket, and I'm don't think it will be compatible with the bafang kit, at least not initially or without fabricating a special bracket for it.
I was also hoping to find something a bit cheaper than that, although maybe that's unrealistic.
She really doesn't want a lot of power, and is happy to pedal and go slow. Mostly she was looking for a little help with the hills and a boost at low speed to make it a bit easier. But maybe a powerful kit used lightly is the best route.
Most of our trips will be in the 5-15 mile range, to school, to the grocery store. And when we are riding together which is most of the time I will likely have the cargo bike and our daughter.
I was leaning towards a higher voltage battery battery to save weight but perhaps that isn't true, and to carry with me as a spare when I am riding the cargo bike solo for longer trips.
I don't mind the added complexity of the rear hub kit, I was planning on stripping her bike down and rebuilding it with upgraded components when we do the ebike kit anyways.
Thanks for the suggestion to check out ebikes.ca, I hadn't looked there.
I was looking at the Mac rear hub at em3ev.com, seems like it might be a good way to go. Would you suggest the max torque winding for that motor? How is the PAS with that system if we didn't get the expensive v3 display.
Can you do a PAS system with the Luna cycle geared hub motor? Doesn't seem like there is much info about their hub, for torque or speed?
Thanks again.
Lebn

 

[dogman dan]

Link to the lift. https://www.kickstarter.com/projects/1616617044/the-lift-cargo-bike

Too much weight for any of the geared hubs out there, and that big hill, really. 1000' vertical is a long hill. Maybe I misunderstand, and it's less than a quarter mile long 10% hill.

But in any case, even for flat riding, you are now talking about a really heavy bike. It needs the durability, and better heat shedding ability of a DD motor.

But an even better solution would be a mid drive.

So it depends on what you want, a cheap solution or the best solution. A cheap DD motor will do, but a mid drive will be the best.

 

[lebnjay]

Thank you for the reply,
Sorry I wasn't clear, the hill is only about 100' vertical, and about 1,000' long.
The cargo attachment is about 30lbs, the bike is about 30lbs, add in my wife, ebike kit, and cargo weight and we have about 270lbs.
I was under the impression that the geared hubs did better at low speed and with higher torque, and the dd Hub's were better once you got moving, is that not true?
I know mid drive would be the best, I just don't know how it would work with the cargo attachment.
What if we electrified the Lift? Put a hub motor in the front wheel, and a separate throttle with a quick disconnect?
What hub motor would you recommend for that?
We would still want to add a kit to my wife's bike, but then it wouldn't have to deal with the extra weight of the cargo attachment on its own.
And really she will likely only be pushing the cargo attachment occasionally, it will usually be me.
Lebn

 

[e-beach]

Thank you for the reply,
Sorry I wasn't clear, the hill is only about 100' vertical, and about 1,000' long.

Well that is 10% grade for about 5 tenths of a mile...20% of a mile. That is a long uphill grade for any bike.

The cargo attachment is about 30lbs, the bike is about 30lbs, add in my wife, ebike kit, and cargo weight and we have about 270lbs.

The weight does add up quick. And it looks to me that you are underestimating the weight by around 10% or so.

I was under the impression that the geared hubs did better at low speed and with higher torque, and the dd Hub's were better once you got moving, is that not true?

In general that is true, but what Dogman was saying is that the plastic gears in the geared hub motor might not last long under the strain of the weight you will be pushing. If you get a "slow wind" DD motor you could have a torquey motor.

I know mid drive would be the best, I just don't know how it would work with the cargo attachment.

Then it begins to limit your choices to a DD motor.

What if we electrified the Lift? Put a hub motor in the front wheel, and a separate throttle with a quick disconnect?
What hub motor would you recommend for that?

IMO same as the one you might put in the back. A high-ish voltage slow wind motor.

We would still want to add a kit to my wife's bike, but then it wouldn't have to deal with the extra weight of the cargo attachment on its own.
And really she will likely only be pushing the cargo attachment occasionally, it will usually be me.
Lebn

OK, now I am a bit confused....Is your wife's bike a separate bike from the Lift bike?

How many bikes are we talking about here?

 

[tln]

I think the cyclone 300w mid-drive might work well for you. From pictures (I don't have one) it looks like the mounting
would keep the motor higher up on the downtime than the BBS02/HD. And, if the stock mounting does not clear
the cargo crossbar, you could potentially mod it (unlike BBS02/HD).

It'd definitely get up the hill!

 

[lebnjay]

Thanks for the follow up and advise e-beach.
I guess I wasn't clear with the cargo attachment. The front cargo box and frame is a removable attachment, it can convert any standard bike to a front cargo bike. It can then be removed in about a minute leaving you with a normal bike. So you only add the cargo carrying ability when you need it. Most of the time I will be pushing the cargo attachment, but occasionally my wife will.
I guess I need to get out and test ride more ebikes. We test ride a douze cargo bike with the erad mid drive, which I think is the same as the bbs02. It felt great, way better than I expected, but it cost about $6k.
Hopefully one of the shops in Bend will have some direct drive and geared hub bikes I could test out, I'm not familiar with the electric bike scene here but someone must sell them.

That cyclone 3000w system seems intense, I think a bit more trouble than I'd like to tackle for our first build, especially on my wife's bike.
Does anyone do the geared hub motors with metal gears? Why plastic if they don't hold up?

Would you have a recommendation for a slow wind high torque dd motor?
How are they to ride without power?
The direct drive hub seem more like an electric motorcycle to me than a bike for some reason, how is the pedal assist feel with them, does it still feel like riding a bike?
Thanks

 

[lebnjay]

Also, I may be off on the hill measurements to our house, it really doesn't seem too bad. Tomorrow I'll see if I can come
up with a better measurement of it.
Lebn

 

[e-beach]

Also, I may be off on the hill measurements to our house, it really doesn't seem too bad. Tomorrow I'll see if I can come
up with a better measurement of it.
Lebn

Do you have one of those elevation gps things on your phone?

I you use google Earth (it's free) you can measure a hills length with the measuring tool and the elevation (in the bottom right of
google earth). Then use this site to figure it out. http://veloroutes.org/tools/

As an example my local 10% grade hill, Inglewood Blvd is 571 feet long and 62 feet in elevation. That is a steep hill. Lucky for me it is only .108 miles or 1 tenth of a mile. It takes a low gear and me pedaling along with being WOT to move up the hill at a bicycle speed pace. The cars always pass me on the ride up.

 

[Jon NCal]

I think a Mac geared motor in 12T with a 30A controller would work fine. Can get a 48V 13Ah dolphin battery from lunacycle, if it mounts on your bike. 36V battery is also fine, but will only provide 15mph top speed. This type of riding is not really a big stress for the geared motor and the hill will be no problem either.

 

[lebnjay]

Thanks for the tip on using google earth, turns out I was overestimating a bit. The hill to our house has about 65ft of elevation gain over about 700ft, so more like 9% grade.
We really don't mind going slow up this last hill though.
The Mac 12T seems like it would be a good way to go, running it at 48v would be more than enough top speed.
How is the pedal assist with these? Can it be done without the expensive cycle analyst?
Would you recommend getting it from em3ev.com?
Thanks
Lebn

 

[docw009]

To me, pedal assist it is like having power steering on your feet. Feels great to me. Trail riders who need speed control surely want more sophisticated PAS systems. Fast street riders probably are happy with throttles.

Having more power levels available in your PAS allows easier riding at lower speeds. My simplest rig only has 3 levels and I would agree that it's over assisted at slow speed. It will quickly take me up to 10 mph and then it backs off. That's OK for a fast start, but might be trouble in bike path traffic. I either squeeze the brake partially so the motor won't start, or I turn off PAS til I get moving. When my mid drive bike is set to 3 PAS levels, it is also over assisted at level 1. It's possible on the Bafang controller to customize power delivery for each level, but it was simple to choose the 9 levels and the factory settings worked for me. Still, as I noted, basic riding skills allow you to live with PAS if you only have 3 levels.

It's part of riding to me, like dropping back to first gear when coming to a stop. My wife wants to start her bike in a mid gear and always has. In fact, she never shifts. Her e-bike is good to her. The geared motor will take off no matter where she set her shifter.