20" wheel, DD or geared for steep hills?

Hi!
I have a cargo bike with 20" front wheel and need hill climbing help.

Where I live there are some really steep hills, but most often not so long. Most people without motors are walking with their bikes in them. But if you pedal you are probably finished within 10 seconds, but maybe there are also some longer that last 30 seconds. I dont need more top speed than 25-30km/h on the flats since I most often will carry two kids. I have 7 gears on the rear 26" wheel.

Can I use a direct drive motor for this? Or do I have to use a geared? As I understand and have read many say geared are better for hills, but I was wondering if a DD could work since I only have a 20" wheel? But guess I can't use to much power since it is front wheel? (but will use tourqe arms and steel fork).


Also, any suggestions for a DD motor/kit? If there will be a geared I think I will go with MAC.

You left out the choice of 'mid-drive' which would be your best option.
Other than that there is no really big difference between geared and DD drive hub motors under your conditions. Same power = same power - the geared-hub having slightly less torque-shock upon takeoff (easier on the old torque arms) compared to a DD (has to do with internal gears and such in a geared hub)

A DD hub has the advantage of being able to be used as a brake because what goes up eventually has to come back down.

It is on paved street right ?

Since it is a cargo bike with small wheel, and the hills are short, and you are willing to pedal, and you don't need to go fast... Almost any kit will do fine. A Mac or equivalent geared motor kit will be good, any 1000w DD kit will be good too. Installation of a front kit on a steel fork is pretty simple.

The only important decision will be battery type and size, according to your specific requirements about voltsge, range and charging time.

you are kind of at that sweet spot where any motor will be fine. DD would be the winner if the hills were long, but they are short. geared hub would be the winner in a 26" wheel, but it's a 20". A chain drive would be the winner if the cargo box was in the back, but the 20" front wheel implies you have a front box cargo bike (?)

So there's no winner here. Anything you pick will probably be fine.

you do want 500w or more. If you pick a geared hub, you do want a MAC. if you pick a chain drive, you do want a Bafang BBS2 or BBSHD. if you pick a DD hub, you do want one of the mid to lower speed winds.
Other than that, it's just personal preference and budget.

Hej,

You say you are going up steep hills, carry cargo, and some precious cargo ( 2 kids ).

Are you really sure you want to use a front motor ? ?

Stockholm is great in the Summer , I know, but with loose sand/grit/snow/slush etc on the road other times of the year, I would think that a rear hub motor would be best,
along with a little lower air pressure in the rear tire to get the traction you need.

I have no experience with DD hubs, but I do have a rear Mac, mine is a 6 t, in a 650b wheel, and goes up hills with just me and a 56 pound bike, as long as I put 25 amps or more into it at 48 volts, at 48 volts and only 20 amps it does not like hills as much , keep in mind the 6 T is a fast speed/low torque motor ( you want the opposite you want a slow speed/high torque motor ).
Now
With Cargo bike / Cargo and going up hills I would get the 10 t, or better yet a 12 t Mac, in a 26 inch wheel or even use a 24 inch rim/wheel. Yes the 24 inch rims and tires are still available when you know where to look.
There is good news, there is now a new version of the Mac Rear Hub motor that can use a cassette, and when used with the newer Cycle Analyst V 3 , or soon to be released V 3.1 you can set the C.A. ( Cycle Analyst ) to shut off the motor when the inside of the motor reaches a certain temperature. And when going up hills / slow with weight that is a very good feature.

Do you have a Garmin Cycle Computer so you can get us the distance and even more importantly the % of slope the hills you want to go up has ? If not can you borrow one from a friend , it would be helpful to know the Degree/% of slope you are wanting to go up.
If you want , post the streets you want to go up so we can see them on Google Maps.

Also
Let us know what kind of import taxes you would have to pay on the Motor/Display/Controller/Batteries, you do know about Iceland Air ?

Swe said:

Hi!
I have a cargo bike with 20" front wheel and need hill climbing help.

Where I live there are some really steep hills, but most often not so long. Most people without motors are walking with their bikes in them. But if you pedal you are probably finished within 10 seconds, but maybe there are also some longer that last 30 seconds. I dont need more top speed than 25-30km/h on the flats since I most often will carry two kids. I have 7 gears on the rear 26" wheel.

Can I use a direct drive motor for this? Or do I have to use a geared? As I understand and have read many say geared are better for hills, but I was wondering if a DD could work since I only have a 20" wheel? But guess I can't use to much power since it is front wheel? (but will use tourqe arms and steel fork).


Also, any suggestions for a DD motor/kit? If there will be a geared I think I will go with MAC.

Click to expand...

Okay so if I understand you right if I put a limit of say 1000W there is no differnce if I choose DD or geared. But I should take one that has just enough top speed that I need, to be sure to get as much tourqe as possible? Meaning like 10T on a MAC.

The bike is this one, but with bakfiets original box.
https://www.flyingdutchman.bike/our-bikes/bakfiets/milano-bakfiets/

The way I see it you can get a DD for like 400USD including shipping:
http://www.leafbike.com/products/diy-bike-conversion-kit/20-inch-electric-hub-motor-kit/newest-20-inch-48v-1000w-electric-bike-kit-front-wheel-918.html
http://www.leafbike.com/products/diy-bike-conversion-kit/20-inch-electric-hub-motor-kit/newest-20-inch-36v-750w-electric-bike-kit-front-wheel-917.html

Or adding like 100usd to a MAC:
http://em3ev.com/store/index.php?route=product/product&path=50_36&product_id=138

Or adding even more to get the BBS02:
http://em3ev.com/store/index.php?route=product/product&path=50_36&product_id=166
Just keeps getting more and more expensive, so question is if I will win anything or regret if I choose any of them.

With front wheel I need to change fork to disc brakes (50USD) and adding hydraulic brakes. With mid drive I don't need to change anything, but if the IM45 roller brakes are not good enough maybe I still need to change front brake. Otherwise I can save some money in keeping fork and brakes and adding them to the BBS02 pot instead.

Rear wheel is no option.


ScooterMan101:
What to you mean about import taxes? Are any of the alternatives inside EU so I dont need to pay import taxes? Otherwise its the same for everyone. I dont know what you mean about Iceland Air?


Edit:
Bike will be used both on pavement roads and dirt roads.

For normal hills, I think the DD hub has come back as an option. A small wheel like a 20-inch bicycle (or 16/17-inch moped) is the most beneficial feature to make this viable, but...the reason DD is back on the menu is ferro-fluid and fins. Now, a DD motor can shed a lot of heat instead of it building up inside.

Of course the title says "steep hills" so...there's no way to tell if a DD with ferro and fins would work for you unless you try it. Your "steep hills" may not be as bad as my "steep hills". Plus, even after the steepness might be measured, if it isn't that long?...it still might work.

DD hubs can take more heat than geared, and I would further recommend a sensorless controller. Whatever issues come up with using a sensorless controller, you would never need to worry about frying a hall sensor.

Swe said:

With front wheel I need to change fork to disc brakes (50USD) and adding hydraulic brakes. With mid drive I don't need to change anything, but if the IM45 roller brakes are not good enough maybe I still need to change front brake. Otherwise I can save some money in keeping fork and brakes and adding them to the BBS02 pot instead.

Click to expand...

You don't need hydraulic brakes. You probably don't need dick brakes, although Disk brakes would be useful for your bike if you go through a lot of mud/snow/slush with them, otherwise, rim brakes would be fine.

Since most forks have a center hole for a fender mount, you might be able to use it for mounting this style of rim brake without buying a new fork:

spinningmagnets said:

For normal hills, I think the DD hub has come back as an option. Small wheel like a 20-inch bicycle or 16/17-inch moped is the most beneficial feature to make this viable, but...the reason DD is back on the menu is ferro fluid and fins. Now, a DD motor can shed a lot of heat instead of it building up inside.

Of course the title says "steep hills" so...there's no way to tell if a DD with ferro and fins would work unless yuou try it. Your "steep hills" may not be as bad as my "steep hills". Plus, even after the steepness might be measured, if it isn't that long?...it still might work.

DD hubs can take more heat than geared, and I would further recommend a sensorless controller. Whatever issues come up with using a sensorless controller, you would never need to worry about frying a hall sensor.

Click to expand...

The problem with DD is that I dont have any clear options to compare with. If I choose MAC I take the infoneon that em3ev has, BBS02 also have controller included.

Any suggestions on what motor and/or controller that could work, so I have an DD alternative to compare with? I think I have read before that the leaf controllers included is not the best option.

Drunkskunk said:

Swe said:

With front wheel I need to change fork to disc brakes (50USD) and adding hydraulic brakes. With mid drive I don't need to change anything, but if the IM45 roller brakes are not good enough maybe I still need to change front brake. Otherwise I can save some money in keeping fork and brakes and adding them to the BBS02 pot instead.

Click to expand...

You don't need hydraulic brakes. You probably don't need dick brakes, although Disk brakes would be useful for your bike if you go through a lot of mud/snow/slush with them, otherwise, rim brakes would be fine.

Since most forks have a center hole for a fender mount, you might be able to use it for mounting this style of rim brake without buying a new fork:

Click to expand...

You think that brake is so much better that the included roller brakes so I should change even if I go with mid drive, or do you only mean as an alternative if I go with front motor?

A front load cargo bike with a small wheel is a perfect candidate for a front DD hub. It will do good all season because the weight is on the motor wheel. Since the hills are very short you don't have to worry about overheating. DD hubs can stand very high power for short periods.

Off road is another story. Not sure this long cargo bike will ride good in the trails.

I am asking about import taxes, because I don't know how much you have to pay, I thought that People in the E.U. and Scandinavia had to pay close to or even over 20% ?
By the time you add up all the components for an e-bike conversion many of us pay $ 1,000 USD and more. e-bay kits could be cheaper though I have not bought that way.
I am asking you about if you know about Iceland Air because I am not sure what power level motors you are able to import.
Iceland Air has flights as cheap as $ 100 U.S.D. each way from Reykjavic to San Francisco, Los Angeles , and other places in U.S. and perhaps Canada as well, there are places here you can buy from if you / or someone you know, are planing on having a Holiday in the U.S. or Canada anyway.

http://www.ebikes.ca/shop/electric-bicycle-parts/motors/m2706fd.html

I do not know how much from Stockholm to Reykjavic though , how much would that be ?

Swe said:

Rear wheel is no option.

ScooterMan101:
What to you mean about import taxes? Are any of the alternatives inside EU so I dont need to pay import taxes? Otherwise its the same for everyone. I dont know what you mean about Iceland Air?

Click to expand...

MadRhino said:

A front load cargo bike with a small wheel is a perfect candidate for a front DD hub. It will do good all season because the weight is on the motor wheel. Since the hills are very short you don't have to worry about overheating. DD hubs can stand very high power for short periods.

Off road is another story. Not sure this long cargo bike will ride good in the trails.

Click to expand...

I used google transle for dirt road. Maybe the correct word is gravel road, like this one:
http://fultoncountyconservationdistrict.org/sites/default/files/image_assets/dirt__gravel_road.jpg

Dont see much difference riding them than asphalt if you lower the speed. Though have only ride max 500W on a front wheel on normal bike. This is not the main road I have but it is a mix.

But a suggestion on motor and controller would be good.
I have a leaf 1500w today with adaptto but want a ceaper controller this time, and should be able to have that since the power is lower.

You can use a much simpler controller. I agree with some previous post, that a 9C is a good choice for you. Select the winding for 20% above your target speed. A motor and controller are happy at 80% throttle, and the 20% extra will help to maintain you speed when you meet a hill.

9C kits are many, you can find a choice with a simple search. If you want counseling and perfect service, I suggest Justin's shop: http://www.ebikes.ca/shop/electric-bicycle-kits/direct-drive.html

Thanks for all your inputs. But now I am starting to think about mid drive Bafang BBS02 anyway... :? If you take the example on em3ev with a MAC motor and then adding two tourqe arms and a PAS controller/display (I need a walk-mode) and add a higher price of shipping compared to BBS02, then there is not much differnce in price. Actually BBS02 is a little cheaper.

If money is important, buy a 9C clone in China, or a Mac clone if you prefer smaller. A mid drive is always more: More money, more work, more maintenance. Although they are much better than before, they are still more trouble and noise. The inconveniences do make sense on a light weight bike, when you want to retain the original balance and handling feel. They also make sense for off road riders who are into slow technical trails with lots of sharp turns and obstacles, very long climbing, or downhill jumping.

Well MadRhino you are not making this easy I am a bit concerned about the noise from BBS02. Only found this video, and I think it has a high sound but can be hard to tell from a video:

https://www.youtube.com/watch?v=OQvz-S2Gx5Q

Do you have any suggestions of a 9C clone or similair with a controller that is not garbage? I will continue my search but so far I can't find anything... I only need 1000W peak.

Well, I don't use those small motors. I am into fast bikes. Other ES members are more likely to suggest Chinese suppliers according to their own experience. Friends of mine did order complete kits from China at a very good price, mostly on Alibaba where you can find many contacts with manufacturers and suppliers.

One example :
https://m.alibaba.com/product/60347...ml?s=p&spm=a2706.7843667.1998817009.17.VRi2p6

That is not a recommandation, it is only one of so many. You should deal with a supplier yourself, making clear what you want and verify his feedbacks. Price is better buying direct from Chinese manufacturers, but you have to do the communication work.

A couple of things you have to be mindful of when buying what looks like a cheap kit from the internet where you can not talk with
the seller , either by phone, or by e-mail.

1) Cost of shipping , many kits / parts look cheap until you factor in the shipping costs.

2) and even more important. Most all batteries that would come with such a cheap kit, have low discharge rates ( C Discharge Rate ) , like 2 C or less,
best to get a battery that has at least 5 C Discharge Rate and above like 10 C ... etc.

You think these thin forks will stand 1000W if they have two tourqe arms? On a heavy cargo bike...

You think these thin forks will stand 1000W if they have two torque arms? On a heavy cargo bike...

Click to expand...

Yes...TWO torque arms.