Comparing DD vs geared motors : Best setup for city commute

General Discussion about electric bicycles.
Post Reply
Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Comparing DD vs geared motors : Best setup for city commute

Post by Choudhary » Jun 28, 2017 10:47 am

Namaste. I am from India & have been working on ebikes for sometime. I was using MXUS (Chinese) geared hub motors (250 watts) in my bikes & was happy with them but they were expensive for Indian market. I visited Shanghai Cycle fair to get more understanding of ebike technology & spent some time there. I feel that Chinese ebike market is quite evolved and most motors have a reliable life of around 3 years (any info on this?).

Following are the requirements & conditions where these bikes will be running.
1. Range 50km. Max Speed 25kmph
2. Mostly flat (except flyovers)
3. Indian weather is hot most of the time. So pedalling is only an emergency / leisurely option & bike will be running on throttle most of the time.
4. Just like China, the bike will often carry 2 people (150kg)

While using MXUS 250 watt geared motor with 36v 7.8ah, I was getting 35-40km range (varrying on traffic) & around 25km with 6.6ah, which i think is great.
With a new Direct Drive motor (an option that my vendor supplies), I am supposed to get 50km range on 48v 10ah. This increases my battery cost by a big percentage. But there is one feature in DD that I absolutely love, that is, automatic anti theft lock / alarm.

My questions are, given the requirements & conditions where the bike will be used
1. Should I go for 36v setup or 48v? (although India has a limit of 250watts for exempting electric 2 wheelers, most run on 48v 20amp controllers)
2. what difference in battery capacity should I expect for 50km range for the two kind of motors?
3. I understand geared motors have higher torque (higher initial acc. & better climbing for same wattage), slightly higher noise, possibility of wearing out gears sooner than DD. But is there a major performance difference that I am missing and becomes important in Indian context (or my usage)?

Few comparison:
Geared Motor vs Direct Drive Motor
Company - Mxus || Local Manufacturer
Price - 55 usd || 32 usd
Warranty - 2 years || 1 year
Weight - 2.8kg || 4.5kg
Voltage - 36v || 48v
Inclines - Slows down a while climbing flyovers (comes down to 20kmph) || Does not slow down
Controller amperage - 7amp to 14amp || 10amp to 13amp (this is a little hard for me to digest. they say the motor is 240 watt. How :? )

Attached is the pic of the bike I am working on now. Any suggestions & piece of info are welcome.
Image

Edit - couldn't get the image to show up. You can check it here http://imgur.com/a/srMcB

User avatar
Drunkskunk
100 GW
100 GW
Posts: 7059
Joined: Apr 14, 2007 11:37 am
Location: Dallas, Texas. U.S.A.

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Drunkskunk » Jun 28, 2017 12:49 pm

At a constant speed on level ground, the direct drive (DD) is going to be more efficient, quieter, and more robust. Also, on long inclines or when overloaded, a direct drive is much better able to handle the heat buildup.

For everything else, a geared drive is better.

Those little MXUS geared hubs aren't very strong. the 250w and 350w were more or less the same motor. Mine only lasted 8 years of being abused. :mrgreen:
I wouldn't replace the motor with another of that size. the 500w are much more strongly built. since power output is dependent on the controller, it's easy enough to de-tune the motor to run at 250 watts. And easy enough to label the 500w motor as a 250w motor then.
Buy the ticket, take the ride.
Monster Bike:https://endless-sphere.com/forums/viewto ... =6&t=38667

User avatar
The fingers
100 GW
100 GW
Posts: 6065
Joined: Mar 11, 2012 11:22 pm
Location: Desert Pacific Cali USA

Re: Comparing DD vs geared motors : Best setup for city comm

Post by The fingers » Jun 28, 2017 1:40 pm

You might want to pedal to help the DD hub up the incline of a flyover to keep the revs up if necessary to prevent lugging, but they have a nice moderating effect on speed descending down the other side of the hill which I like most times being inches from disaster.
Black Schwinn High Sierra
Blue Schwinn Cruiser 5
Blue Schwinn High Plains
Black Fiore Cruzer 5: Amped Warp Drive 26" Front DD/SLA kit
http://ghostbikes.org/
http://www.rideofsilence.org/main.php
Hebrews 9:27

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jun 28, 2017 3:56 pm

Drunkskunk wrote: At a constant speed on level ground, the direct drive (DD) is going to be more efficient, quieter, and more robust.
For everything else, a geared drive is better.
So does that mean that for city use, with frequent traffic signals & crazy indian traffic, geared will give better range & performance and should be more preferred?
I wonder why almost every electric scooter (3 million sold every year there) in China has direct drive motor if it is not better suited for cities. A small reason i can think of is cost,
but then, cost is not really a big factor there as they can control it any day by making millions of motors. The other reason could be that these scooters use higher wattage motors
& perhaps DD becomes preferable in larger power. Do you think so?

I mean, i just haven't been able to see any clear advantage of geared over DD in my context. we don't want super zippy bikes, hills don't exist, and small flyovers, i believe could be done easily with a 48v 13amp setup. Except, of course, the mileage. Is there a clear & big difference between the mileage of two?

Or maybe, the drag felt while pedalling in DDs (as i have read in a lot of threads & articles)
Drunkskunk wrote: Mine only lasted 8 years of being abused. :mrgreen:
I knew MXUS is reliable but 8 years is absolutely amazing. I need to rethink about MXUS. :D
Last edited by Choudhary on Jun 28, 2017 4:26 pm, edited 1 time in total.

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jun 28, 2017 4:03 pm

The fingers wrote:You might want to pedal to help the DD hub up the incline of a flyover to keep the revs up if necessary to prevent lugging, but they have a nice moderating effect on speed descending down the other side of the hill which I like most times being inches from disaster.
I sometimes pedal on MXUS geared (36v x 15amp) as i feel it slows down a little on flyovers but don't need to do so. Instead of 25kmph, it pulls me just fine at ~22kmph. Do you think that a 48v x 13amp bike will slow down similarly?
For the moderating effect on downhills, is that because of DD magnets? I read almost everywhere that coasting / pedalling on DD bikes is not fun as compared to geared hubs. Whats your experience?

User avatar
The fingers
100 GW
100 GW
Posts: 6065
Joined: Mar 11, 2012 11:22 pm
Location: Desert Pacific Cali USA

Re: Comparing DD vs geared motors : Best setup for city comm

Post by The fingers » Jun 28, 2017 4:26 pm

I coast most all the time, just pedal on start ups from a stop and when needed on hills. Ghost pedal when there are cops or to razz recreational riders. :mrgreen:
Black Schwinn High Sierra
Blue Schwinn Cruiser 5
Blue Schwinn High Plains
Black Fiore Cruzer 5: Amped Warp Drive 26" Front DD/SLA kit
http://ghostbikes.org/
http://www.rideofsilence.org/main.php
Hebrews 9:27

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jun 28, 2017 4:59 pm

The fingers wrote:I coast most all the time. Ghost pedal when there are cops or to razz recreational riders. :mrgreen:
Hahaha.....that is a good piece of info. I will have to try the bike myself to understand better. sample arrives in a week.
The idiot that I am, tried all kinds of geared motors & after discussing with them finalized on DD motor without trying it on the bike. They told me everything is pretty much the same and i took their word for it. Now when it came to buying battery, I am supposed to spend almost 1.5 times of what i was expecting for 50km range (13s5p instead of 10s4p) and hence all the ruckus. :mrgreen:

What mileage do you get on your DD?

User avatar
The fingers
100 GW
100 GW
Posts: 6065
Joined: Mar 11, 2012 11:22 pm
Location: Desert Pacific Cali USA

Re: Comparing DD vs geared motors : Best setup for city comm

Post by The fingers » Jun 29, 2017 2:44 am

I would be hard pressed to go 10 miles on saggy lead boat anchor batteries. :lol: Right now bike moved to storage for a few weeks at least until we move and get settled.
Black Schwinn High Sierra
Blue Schwinn Cruiser 5
Blue Schwinn High Plains
Black Fiore Cruzer 5: Amped Warp Drive 26" Front DD/SLA kit
http://ghostbikes.org/
http://www.rideofsilence.org/main.php
Hebrews 9:27

User avatar
dogman dan
100 GW
100 GW
Posts: 34682
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Comparing DD vs geared motors : Best setup for city comm

Post by dogman dan » Jun 29, 2017 6:19 am

Well, I see you chose a dd, and that's fine. It is the lowest cost, most reliable motor ever made.

In my opinion, the best setup for city commutes is a 500w rated, geared, rear hub motor. Run on 36v or 48v, depending on the speed you need. ( Typically with 48v, that's a 1000w setup)

Why? All the stops and starts make a dd much less efficient in the city. No to a mid drive for similar reasons, having to shift a lot gets to be a pain.

Why not a 350w rated motor? Indeed, running them at 750w is plenty of power. However, in the city, its just that nice to have the full power, and fast take off, of a larger geared motor and 48v. But you might find the smaller motor perfectly adequate, especially if the traffic is so bad you really can't take off fast anytime.

Philaphlous
100 W
100 W
Posts: 180
Joined: Mar 28, 2017 7:17 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Philaphlous » Jun 29, 2017 1:54 pm

I'd like to add my 2 cents. If you go direct drive be prepared to see some really hefty loads when accelerating. I really have to back off the throttle with my 48v beast. Easily getting upto 1400w+. It's awesome because there's such a wide speed range but you do feel a slightly sluggish accelerating if you're watching the power draw...

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jun 29, 2017 3:17 pm

dogman dan wrote:
Why? All the stops and starts make a dd much less efficient in the city.
I want to ask how much less efficient :mrgreen: , but I think the best way to find out is by myself :) . My sample should arrive next week. And I will try to post how the new DD faired against MXUS geared.
dogman dan wrote: Why not a 350w rated motor? Indeed, running them at 750w is plenty of power. However, in the city, its just that nice to have the full power, and fast take off, of a larger geared motor and 48v. But you might find the smaller motor perfectly adequate, especially if the traffic is so bad you really can't take off fast anytime.
Always good to get insights like this from you. Just as you said, the roads are quite crowded (check this photo. this is normal for us http://imgur.com/a/L5Soh), so high power does not make sense.
A thing I don't understand is can the rating of motor be changed? I mean, as i mentioned above, there are ebikes in India (i myself had one for 5 years) running on 48v & 20amp controllers, being exempted by Govt. This means its 'max power is under 250 watt & max speed is 25kmp'. (check point number 2 https://www.araiindia.com/faqs_electric_vehicle.asp) How does this happen?

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jun 29, 2017 3:20 pm

Philaphlous wrote:I'd like to add my 2 cents. If you go direct drive be prepared to see some really hefty loads when accelerating. I really have to back off the throttle with my 48v beast. Easily getting upto 1400w+. It's awesome because there's such a wide speed range but you do feel a slightly sluggish accelerating if you're watching the power draw...
Thanks for sharing this. I guess, acceleration is not DDs strength. Will let you know my experience once i assemble mine.

User avatar
dogman dan
100 GW
100 GW
Posts: 34682
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Comparing DD vs geared motors : Best setup for city comm

Post by dogman dan » Jun 30, 2017 6:22 am

The sometimes more sluggish acceleration of he dd is what makes it less efficient at starts and stops. 20% less, if you stop every block. Hardly noticeable if you stop every 5k.

FWIW, the way to end the sluggish acceleration of a dd is to heave power at it. then they take off so fast, they don't run inefficient. it does though, cost you to haul ass.


Re the motors. Motors come with a wattage specification. this means that if you run this motor at 500w, or whatever, then it will never overheat unless too heavily overloaded. Most motors easily take 3x the rating, because this over watt condition is brief, at start up.

So when I say 500w rated motor, I mean motor spec. most "48v 1000w" kits will have a 500w rated motor in the kit, geared or DD.

MikeSSS
100 W
100 W
Posts: 102
Joined: Jul 31, 2016 10:52 pm
Location: San Antonio, TX

Re: Comparing DD vs geared motors : Best setup for city comm

Post by MikeSSS » Jul 02, 2017 6:15 pm

I use an Aotema direct drive front hub motor. Battery is sometimes 36v gel cell, but most often 48v 13.5ah GA cell Shark pack from Luna. A friend uses a front gear drive hub motor from Luna, I ride this occasionally. His bike uses the same 48v 13.5ah GA cell Shark pack from Luna that my bike uses.

My riding is in the 11 to 16 mph average range, with enough sprint ability to outrun dogs. I don't push it, especially starting from a stop and especially starting from a stop uphill.

From 8mph to top speed of 25 mph, both bikes run side by side at full throttle. The bikes and riders weight is about the same.

There is some gear whine from the geared hub, and some harmonic noise from the direct drive hub. Neither is loud, neither attracts attention, both are seldom noticed by walkers and other bikers. Even "coasting uphill" is seldom noticed. (My gas bike is noticed, even though it is relatively quiet.)

The geared hub motor gives better acceleration from a stop, normally this is not needed, but starting from a stop on an uphill incline, it is a big advantage. Wheel weight for the geared hub is about 15lb, but is 25lb for the direct drive. Fixing a flat on the geared hub wheel is easier than with the direct drive. This is important with respect to lower back pain, for a few days after the flat tire.

My next ebike will use a geared rear hub motor, on an upright seating position, comfort bike. Why? Lighter hub motor wheel is better than heavier. Better for ride quality and better for flat fixing. Besides that, it stresses the frame less and metal fatigue is real, especially for aluminum, because aluminum can't take the flexing cycles.

Rear hub motors allow the use of a bike with suspension fork and suspension seat post or a bike with full suspension. I'm old, so ride quality is a big deal, especially with respect to stress on the spinal column, especially the discs between the vertebrae. I have no spine problems and don't want any.

Well that's it. PS, pay attention to what Dogman Dan says. He has a lot of experience and "experience is knowledge", thus said Albert Einstein.

User avatar
MadRhino
100 GW
100 GW
Posts: 5067
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Comparing DD vs geared motors : Best setup for city comm

Post by MadRhino » Jul 02, 2017 10:13 pm

Choudhary wrote:Namaste. I am from India & have been working on ebikes for sometime. I was using MXUS (Chinese) geared hub motors (250 watts) in my bikes & was happy with them but they were expensive for Indian market. I visited Shanghai Cycle fair to get more understanding of ebike technology & spent some time there. I feel that Chinese ebike market is quite evolved and most motors have a reliable life of around 3 years (any info on this?).
Motors should last more than 3 years, running 250w especially.

A MXXUS geared hub is not expansive. Well maybe it is for India, but you can't go much lower cost reliably.

A DD hub is more reliable, can be fed more power but also likes more power to come alive. At 250w you should stay with geared hubs.

Carrying a passenger will cut on range, considerably. So yes, you need to invest into bigger battery.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jul 07, 2017 3:29 am

dogman dan wrote: The sometimes more sluggish acceleration of he dd is what makes it less efficient at starts and stops. 20% less, if you stop every block. Hardly noticeable if you stop every 5k. FWIW, the way to end the sluggish acceleration of a dd is to heave power at it. then they take off so fast, they don't run inefficient. it does though, cost you to haul ass.
Re the motors. Motors come with a wattage specification. this means that if you run this motor at 500w, or whatever, then it will never overheat unless too heavily overloaded. Most motors easily take 3x the rating, because this over watt condition is brief, at start up. So when I say 500w rated motor, I mean motor spec. most "48v 1000w" kits will have a 500w rated motor in the kit, geared or DD.
20% less is quite a big number. I guess I have to stick with geared motors. Thanks for giving such specific info. :D

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jul 07, 2017 3:42 am

MikeSSS wrote:I use an Aotema direct drive front hub motor. Battery is sometimes 36v gel cell, but most often 48v 13.5ah GA cell Shark pack from Luna. A friend uses a front gear drive hub motor from Luna, I ride this occasionally. His bike uses the same 48v 13.5ah GA cell Shark pack from Luna that my bike uses.

My riding is in the 11 to 16 mph average range, with enough sprint ability to outrun dogs. I don't push it, especially starting from a stop and especially starting from a stop uphill.

From 8mph to top speed of 25 mph, both bikes run side by side at full throttle. The bikes and riders weight is about the same.

There is some gear whine from the geared hub, and some harmonic noise from the direct drive hub. Neither is loud, neither attracts attention, both are seldom noticed by walkers and other bikers. Even "coasting uphill" is seldom noticed. (My gas bike is noticed, even though it is relatively quiet.)

The geared hub motor gives better acceleration from a stop, normally this is not needed, but starting from a stop on an uphill incline, it is a big advantage. Wheel weight for the geared hub is about 15lb, but is 25lb for the direct drive. Fixing a flat on the geared hub wheel is easier than with the direct drive. This is important with respect to lower back pain, for a few days after the flat tire.

My next ebike will use a geared rear hub motor, on an upright seating position, comfort bike. Why? Lighter hub motor wheel is better than heavier. Better for ride quality and better for flat fixing. Besides that, it stresses the frame less and metal fatigue is real, especially for aluminum, because aluminum can't take the flexing cycles.

Rear hub motors allow the use of a bike with suspension fork and suspension seat post or a bike with full suspension. I'm old, so ride quality is a big deal, especially with respect to stress on the spinal column, especially the discs between the vertebrae. I have no spine problems and don't want any.

Well that's it. PS, pay attention to what Dogman Dan says. He has a lot of experience and "experience is knowledge", thus said Albert Einstein.
Thanks for sharing your experience Mike. This really helps. Will try my to compare my geared & DD side by side and share my experience here. And yes, I do take Dogman's words very seriously. :D

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jul 07, 2017 3:45 am

MadRhino wrote: A DD hub is more reliable, can be fed more power but also likes more power to come alive. At 250w you should stay with geared hubs.

Carrying a passenger will cut on range, considerably. So yes, you need to invest into bigger battery.
Yes. The manufacturer say that I will need at least 48v 10ah for 50km. In my understanding, with a passenger this range will come down to ~30km.

User avatar
dogman dan
100 GW
100 GW
Posts: 34682
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Comparing DD vs geared motors : Best setup for city comm

Post by dogman dan » Jul 07, 2017 6:30 am

Or more. A passenger may slow your speed to the point where you are running the motor too slow, making heat with your power.

At that point you not only run at 50% efficiency, you will possibly smoke motors.

The best hub motor setup for really heavy weights starts with a very small wheel, like 20", and a direct drive motor that can handle running at less efficient rpms. If the motor is big enough, run lots of power so you stay out of the inefficient rpm ( when heavily loaded) for the motor.

If you cannot run enough power to keep that motor efficient in 20" rim, ( because of the overload) that is when you resort to lower rpm motors. A 48v 20 amps setup with a cheap 9 c type motor can haul an amazing weight efficiently, if the motor is closer to 200rpm than 350, @ 36v. It will still max out at about 400 pounds, for any kind of hills.


The very best way to haul an overload, is with a mid drive. Then you can gear the motor down, so that the motor spins fast and efficient, when the bike is going 5 mph up a steep hill, loaded to the max.

heavymetalthunder
100 W
100 W
Posts: 186
Joined: Oct 07, 2013 9:46 pm

Re: Comparing DD vs geared motors : Best setup for city comm

Post by heavymetalthunder » Jul 11, 2017 2:55 pm

For the city commute a DD 750w to a 1000w at 48V would work out well. For the city commute a e-bike needs a few extra items to make it safer, day/nigh head/tail lights set up. Because I ride motorcycles you might consider besides the lights, installing stop lights, turn signals, and a horn as add on later. You can get picked off on driveways and busy streets as drivers don't always see you coming. All of these items are 12v powered so I used a golf cart transformer 48v to 12v to power it so it was a reason why I went to 48v. For me riding with a helmet, gloves, high visibility safety vest is must, and I also wear knee pads as I once took a minor fall a couple of years ago land hit my knee and it took a trip to the ER and a week to heal. For the city commute don't use mountain bike tires get yourself some decent road tires which gives you a smoother ride with better mileage. An air pump, spare inner tube or patch kit, and tools are needed if you have a flat, and through the years I've had three flats.

heavymetalthunder
100 W
100 W
Posts: 186
Joined: Oct 07, 2013 9:46 pm

Re: Comparing DD vs geared motors : Best setup for city comm

Post by heavymetalthunder » Jul 11, 2017 3:02 pm

The fingers wrote:I coast most all the time, just pedal on start ups from a stop and when needed on hills. Ghost pedal when there are cops or to razz recreational riders. :mrgreen:
I do the same thing too :

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jul 13, 2017 3:43 pm

dogman dan wrote: The best hub motor setup for really heavy weights starts with a very small wheel, like 20", and a direct drive motor that can handle running at less efficient rpms. If the motor is big enough, run lots of power so you stay out of the inefficient rpm ( when heavily loaded) for the motor.
I guess thats why this is the most common setup for most e-scooters / mopeds. I have come to realize slowly that what I am making is no longer a bike but more of an e-moped that can be used as a bike recreationally. Currently I have a 22" setup which I plan to change to 20inch fat tires like Lithium Super 73, or Moke - ebike. Finally it all comes to how can I manage to give a good reliable product at a decent price. I wonder how did sondors manage to offer his bike for ~$650 with all A-grade components (i saw his campaign and initially the target was 100-200 bikes, which is not a lot for bringing down the costs drastically).

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jul 13, 2017 3:48 pm

heavymetalthunder wrote:For the city commute a DD 750w to a 1000w at 48V would work out well. For the city commute a e-bike needs a few extra items to make it safer, day/nigh head/tail lights set up. Because I ride motorcycles you might consider besides the lights, installing stop lights, turn signals, and a horn as add on later. You can get picked off on driveways and busy streets as drivers don't always see you coming.
I agree. I have a headlight, tail light setup and plan to add turn signals later. But Indian traffic is a different ball game altogether. These safety precautions do matter but play little role in your reaching home safely. :mrgreen:

Choudhary
10 mW
10 mW
Posts: 33
Joined: Sep 12, 2016 1:54 am

Re: Comparing DD vs geared motors : Best setup for city comm

Post by Choudhary » Jul 25, 2017 6:03 am

Some new developments around this ebike. Normal buyers find ebike way too much expensive for their use in India & hence are reluctant to buy it. I have been talking to home-delivery companies (who use 100cc motorcycles currently) for using this ebike and they seem very interested in it. This ebike does the needed job & saves loads of money for them. So now, I have to make an ebike which is most suited for the following numbers

1. Daily distance - 100 km. So i provide them with 2 battery packs, each of >50km range.
2. The vehicle stops every 1.5km -3km for a delivery.
3. Weight = 75kg (rider) + 30kg (delivery weight) = 105kg.
4. Rough riding. People generally take some care when riding their own vehicle. But when riding companies vehicle, delivery boys can be very rash & rough in their riding.
5. Speed = 25kmph max. Only city riding.
6. Assume it would be throttle driven 99% of the time & pedals are there only for extreme emergency. Terrain is 90% flats but the bike should not slow down on inclines of flyovers.

This use case is different from my previous posts. As range (mileage), and reliability of components (because of the rough use) become extremely important now.
So, my questions are -
1. What is the best setup (best mileage, performance is not an issue now) for this use case considering the weight, frequency of stops, product life. 36v or 48volt? Direct drive or geared. (I know Dogman very clearly mentioned that if the bike stops every block, DDs use 20% more batteries. But some factors have changed, so i wanted to be doubly sured.)
2. This use, that is, 100km daily + rough riding, will take a lot of toll on motor, controller, battery. Even if the motor, controller lasts 1 year, everyone will be happy. But should I still go for relatively lesser known brands like Haobo or go for mxus or even bafang.

I should also mention, that I own all the bikes in the arrangement. I am renting these ebikes to last mile delivery companies, providing free maintenance. I have assumed that I will have to change the motor + controller in 12months - 18 months time. Please suggest your opinions on the built & components of ebike in the above mentioned setup. :)

LI-ghtcycle
1.21 GW
1.21 GW
Posts: 3875
Joined: Aug 29, 2009 11:39 pm
Location: Oregon City Oregon

Re: Comparing DD vs geared motors : Best setup for city comm

Post by LI-ghtcycle » Aug 20, 2017 11:02 am

Choudhary wrote:
dogman dan wrote: The best hub motor setup for really heavy weights starts with a very small wheel, like 20", and a direct drive motor that can handle running at less efficient rpms. If the motor is big enough, run lots of power so you stay out of the inefficient rpm ( when heavily loaded) for the motor.
I guess thats why this is the most common setup for most e-scooters / mopeds. I have come to realize slowly that what I am making is no longer a bike but more of an e-moped that can be used as a bike recreationally. Currently I have a 22" setup which I plan to change to 20inch fat tires like Lithium Super 73, or Moke - ebike. Finally it all comes to how can I manage to give a good reliable product at a decent price. I wonder how did sondors manage to offer his bike for ~$650 with all A-grade components (i saw his campaign and initially the target was 100-200 bikes, which is not a lot for bringing down the costs drastically).
I have come to this same conclusion over the years, I have been building my own Ebikes mainly from DD hub motors, but I have also experimented with a number of different types, friction drive, mid-drive, (recumbent Vision R-40 with Golden Motor in-runner) and I have come to similar conclusions about DD vs geared, but here is what I will add.

If you want to have a product that will just work, and be the "Klashnikov Rifle" of Ebikes, you need a good DD hub, especially as you have described for the delivery companies that will be abused. Where you live, it is VERY hot, so you need to consider several factors:

1) Simplicity - Should be able to be ridden by the average user and take their abuse/use

My father had a nasty bicycle accident in 2007, and we got into Ebikes to help get him back on a bicycle, he is probably the worse case customer for motor abuse. He started with a DD Amped Bikes motor (later sold as 9C, same motor design, different company) and As far as I know, that motor is still being used today, with no issues!

We tried an Amped bikes geared hub motor, for all the advantages we have all seen listed in this thread, however, my father would almost not pedal at all starting the bike (brain injury prevented his really understanding the importance of this) and he killed a 350 Watt geared hub motor about every 1 yr to 6 months, and then we went back to the heavier DD because it just worked. His ride has no real hills, and he would see top speeds of around 28 MPH but this is because he liked the speed and pedaled hard too, but he always stays in top gear, so at the start the motor has to do everything, and he gets going just fine at 36V to boot.

2) Durability - Should not require maintenance more than a bicycle

This is kind of a misnomer, because ALL Ebikes require more than a regular bicycle, (battery, greater speeds/power increase wear etc.) but the goal is to keep it as simple and minimal as possible.

Eventually, all geared motors WILL require replacement or at least maintenance of the gears, a DD doesn't really have these kinds of requirements, other than extreme wet climates (rust builds up inside and can eventually corrode the wiring inside), and normal replacing of worn bearings like anything mechanical.

3) Cost Effective - Should be the best all-round for up-keep and maintenance costs (see reliability)

For your use, both for the delivery businesses and regular customers, I would decide what speed you want to shoot for as the average cruise speed in traffic, get a DD hub motor that has the windings to be most efficient at this speed, match the battery (the main reason that my father got good performance with just 36V was because it was a high out-put Li-Ion battery more than anything else) and use the "industry standard 1000w Motor w/ 20 Amp controller" and limit it to legal power/speed by the battery.

Geared hub motors are a good choice for more experienced Ebike users or just people who are mechanically minded and won't accidentally abuse them, and can be great, but I wouldn't want to be in the business of replacing these gears, on some motors, it is cost prohibitive to do so, and the entire motors are just replaced instead, so if you choose a geared motor, make sure the manufacturer supports replacing gears, not all do.

You really can't beat the simplicity and low nearly maintenance free DD hub motor. I don't personally care for them in the rear wheel, I make custom set-ups with the DD hub as a mid-drive so I have a still gearless Ebike motor, but all the advantages of a geared set-up as now the Ebike motor can use the bicycle transmission.

I have also been impressed by the BBS02 and BBSHD mid-drives from Bafang, these are much higher cost systems, but so much more advantage, that you can get almost twice the distance out of the same capacity of a typical Ebike battery, even with a relatively inefficient 80% motor, compared to the DD motor in the wheel that will at most times be much less than the rated %80 efficiency because you aren't able to ride at full throttle, and much of your power goes to waste heat.

Full disclaimer, I build Ebikes to sell, but I am first an enthusiast and DIY builder at heart!

Good luck in your business in India. :D
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
Back on track E-Bronco! Now with Cro Motor Mid-Drive Goodness!
https://endless-sphere.com/forums/viewt ... 28&t=44997

Vision R40 w/3000w MXUS as mid-drive, NuVinci N171B rear wheel as transmission, Silent yet powerful, running 72v 11.6 ah (20s 18650 Li-Ion) to climb hills, tow trailer with zero pedaling when needed!

https://endless-sphere.com/forums/viewt ... 28&t=75247[/size]

Post Reply