Total newbie question motor position
#1
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Thread Starter
Total newbie question motor position
Hello. First post here. I am familiar with the GREAT advise available on forums like this. I come knowing very little about e bikes. In my younger years, I rode as my primary mode of transportation, but due to health, I have not ridden at all in 30 years. I think an E bike would be a great way to get around when we go camping, both around the campground and nearby trails. Right now, I barely know enough to ask intelligent questions. Please be gentle.
I understand the mechanical difference of front hub, rear hub and mid motor designs. When riding an E bike, what difference do these styles make in ride, handling, braking, etc.
I assume a mid motor design takes advantage of the gearing of the derailleur or internal hub gearing.
Thanks in advance for this education.
I understand the mechanical difference of front hub, rear hub and mid motor designs. When riding an E bike, what difference do these styles make in ride, handling, braking, etc.
I assume a mid motor design takes advantage of the gearing of the derailleur or internal hub gearing.
Thanks in advance for this education.
#2
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My experience includes owing a front drive, one mid drive and several rear drives. Most of these are home built conversions, all inexpensive. And all in the context of ridng in a flat area, mostly under 15 mph.
Front drive is mainly for smooth pavement. Most forks with shocks aren't strong enough for the added weight of a front drive, so it's not good for mild trail or bad streets where the added banging/crunching will stress the axle. Does make the front of bike feel heavy when lifting. Can slip on loose surfaces starting out or going uphill. If you're going to buy a bike, not many front drives anyway.
I see no negatives with my Mid drive, other than it was my expensive kit. One has to keep riding it like a bike though, i.e., downshift to low gear when coming up to a stop so the bike an start easier.Keep it at a high spin rate going up long hills.
Rear drive also has little tradeoffs.
I guess my main advice is to avoid front drive. Some people and a few companies make it work, but why choose the weakest link approach for your first venture into ebiking,
Front drive is mainly for smooth pavement. Most forks with shocks aren't strong enough for the added weight of a front drive, so it's not good for mild trail or bad streets where the added banging/crunching will stress the axle. Does make the front of bike feel heavy when lifting. Can slip on loose surfaces starting out or going uphill. If you're going to buy a bike, not many front drives anyway.
I see no negatives with my Mid drive, other than it was my expensive kit. One has to keep riding it like a bike though, i.e., downshift to low gear when coming up to a stop so the bike an start easier.Keep it at a high spin rate going up long hills.
Rear drive also has little tradeoffs.
I guess my main advice is to avoid front drive. Some people and a few companies make it work, but why choose the weakest link approach for your first venture into ebiking,
Last edited by Doc_Wui; 10-26-19 at 10:47 AM.
#3
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Go test ride some bikes and see which motor position works for you. Your weight, the terrain, etc., all will impact how it rides.
#4
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Good advice ^^^. Since it's doubtful you'll be riding severe hills or technical off road, probably a rear hub motor will be the best option. Only reason in general for front hub is IGH (internal gear rear hub), belt drive or cargo bike IMO.
#5
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The more recent conversion is an early '90s Trek 720 with 38-622 tires on Velocity Dyad rims, using a 36V 500W TSDZ2. No throttle, torque sensor BB - you have to pedal to get assist. Assist levels are 50%, 100%, 200% and 400% increase in torque, limited to a maximum current of 12A (user selectable, default is 16A, but I want to preserve the gear). With the 42T chainring, and 12-36 9 speed cassette, I am limited to a bit above 20 mph due to my limited pedalling speed. I have a 52T chainring on order, which will push it over 25 mph. On a 12-14 AH, 36V battery, I am using less than half the charge for a round trip (no charging at work). The bike is ~25 lbs lighter than the BEAST, is much more relaxing to ride.
I have no ground clearance worries for my commuting - and would choose the TSDZ2 over any other conversion, because of the torque sensor system and its low weight.
If ground clearance is a concern, neither BaFang nor Tong Sheng are good choices because they hang down below the BB.
I have no ground clearance worries for my commuting - and would choose the TSDZ2 over any other conversion, because of the torque sensor system and its low weight.
If ground clearance is a concern, neither BaFang nor Tong Sheng are good choices because they hang down below the BB.
#6
In my experience, when choosing a motor location I first, ask who’s going to be using the bike. Is this going to be a bike for a young or elderly person?
For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
In front hub motors the motor drives the front wheel and you can add to that by applying pedal power. If the motor is installed in the front hub, then the wheel can sometimes slip because the front wheel is less loaded.
One big advantage of the front hub motors is that they have a simple design. If you need to change the tire, it’s very easy to do, whereas, if you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation.
In rear hub motors, the motor pushes the bike forward and it’s very familiar for people since the majority of bikes are built that way.
For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
In front hub motors the motor drives the front wheel and you can add to that by applying pedal power. If the motor is installed in the front hub, then the wheel can sometimes slip because the front wheel is less loaded.
One big advantage of the front hub motors is that they have a simple design. If you need to change the tire, it’s very easy to do, whereas, if you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation.
In rear hub motors, the motor pushes the bike forward and it’s very familiar for people since the majority of bikes are built that way.
#7
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I have no ground clearance worries for my commuting - and would choose the TSDZ2 over any other conversion, because of the torque sensor system and its low weight.
If ground clearance is a concern, neither BaFang nor Tong Sheng are good choices because they hang down below the BB.
If ground clearance is a concern, neither BaFang nor Tong Sheng are good choices because they hang down below the BB.
In my experience, when choosing a motor location I first, ask who’s going to be using the bike. Is this going to be a bike for a young or elderly person?
For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
#8
This observation about the age of the rider is inane. What basis do you have for making this distinction?
The front-wheel usually is less loaded, and there's a chance that it might slip. The rear wheel is usually more heavily loaded. This gives us better pulling power.
Since elderly people have a calm riding style in general and don't need to develop high speeds, the front-hub motor position is more beneficial here. It's much easier in maintenance and gets the job done.
If you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation as changing a tire, for elderly people this can be a real time sink and a hassle.
#9
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Pay attention to battery location as well. I can't stand the feeling of those big batteries mounted on rear racks. Throws the ride off rather badly. Lower and more centered is definitely better.
#10
Yes, as linberl mentioned, the battery location is important.
The rear rack battery location may be reasonable if the motor is installed in front. Then you get a more uniform distribution of the weight of the bike.
Another reason why people may install the battery at the back is that the length of the wires is reduced in this case.
However, probably the most effective location of the battery would be somewhere in the middle of the frame triangle. This arrangement most evenly distributes the weight on the bicycle frame.
Unfortunately, the disadvantage of this location is that it really complicates battery maintenance. The battery replacement can take much longer time.
But again, there are so many different bikes and frames, so each situation can be completely unique.
The rear rack battery location may be reasonable if the motor is installed in front. Then you get a more uniform distribution of the weight of the bike.
Another reason why people may install the battery at the back is that the length of the wires is reduced in this case.
However, probably the most effective location of the battery would be somewhere in the middle of the frame triangle. This arrangement most evenly distributes the weight on the bicycle frame.
Unfortunately, the disadvantage of this location is that it really complicates battery maintenance. The battery replacement can take much longer time.
But again, there are so many different bikes and frames, so each situation can be completely unique.
#11
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Since elderly people have a calm riding style in general and don't need to develop high speeds, the front-hub motor position is more beneficial here. It's much easier in maintenance and gets the job done.
If you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation as changing a tire, for elderly people this can be a real time sink and a hassle.
If you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation as changing a tire, for elderly people this can be a real time sink and a hassle.
Last edited by Moe Zhoost; 12-04-19 at 07:03 PM.
#12
Senior Member
I favour mid-drive systems in purpose-built ebike frames, with derailleur or IGH rear wheel, and with standard bike stem, handlebars, etc. Yes, the frame is bulkier and the whole system is more expensive - but the rest of the components are relatively inexpensive when (not if!) they need replacement.
My shop had a bit of a nightmare with several Stromer e-bikes this past summer.... Not only do they have extremely heavy rear wheel hub drives, but many of their models have a proprietary all-in-one stem and handlebar that was subject to a recall last summer. It was AWFUL.
Then I spent $60 replacing my own e-bike's cassette, chain, and brake pads. (Bosch mid drive system with derailleur). So cheap! So easy! No waiting for weird parts to come from Germany! I can lift the bike into a work stand without 3 helpers or a hydraulic lift!
My shop had a bit of a nightmare with several Stromer e-bikes this past summer.... Not only do they have extremely heavy rear wheel hub drives, but many of their models have a proprietary all-in-one stem and handlebar that was subject to a recall last summer. It was AWFUL.
Then I spent $60 replacing my own e-bike's cassette, chain, and brake pads. (Bosch mid drive system with derailleur). So cheap! So easy! No waiting for weird parts to come from Germany! I can lift the bike into a work stand without 3 helpers or a hydraulic lift!
#13
Member
Thread Starter
In my experience, when choosing a motor location I first, ask who’s going to be using the bike. Is this going to be a bike for a young or elderly person?
For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
In front hub motors the motor drives the front wheel and you can add to that by applying pedal power. If the motor is installed in the front hub, then the wheel can sometimes slip because the front wheel is less loaded.
One big advantage of the front hub motors is that they have a simple design. If you need to change the tire, it’s very easy to do, whereas, if you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation.
In rear hub motors, the motor pushes the bike forward and it’s very familiar for people since the majority of bikes are built that way.
For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
In front hub motors the motor drives the front wheel and you can add to that by applying pedal power. If the motor is installed in the front hub, then the wheel can sometimes slip because the front wheel is less loaded.
One big advantage of the front hub motors is that they have a simple design. If you need to change the tire, it’s very easy to do, whereas, if you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation.
In rear hub motors, the motor pushes the bike forward and it’s very familiar for people since the majority of bikes are built that way.
#14
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Manufactured ebikes will generally have the right kind of forks for a fronnt wheel mount, Home built ebikes should avoid them unless the builder understands where you go wrong. This picture was taken by a kit builder using a 359W motor, Luckilty for him, he wrote that his bike was stopped when the wheel fell off. It lasted for 15 minutes.
I have an ebike with aluminum forks and a 350W motor, and it has dual torque arms. After seeing the above picture, I get nervous all over again. I've marked the axle nuts with a sharpie pen, and they haven't moved.
That's why I think do-it-yourself people should just avoid the issue and use steel forks or a rear drive kit.
I have an ebike with aluminum forks and a 350W motor, and it has dual torque arms. After seeing the above picture, I get nervous all over again. I've marked the axle nuts with a sharpie pen, and they haven't moved.
That's why I think do-it-yourself people should just avoid the issue and use steel forks or a rear drive kit.
Last edited by Doc_Wui; 12-05-19 at 03:15 PM.
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#15
Senior Member
Probably you're safe with dual torque arms; I wouldn't consider a front hub system on anything but steel forks and then use a torque arm too.
#17
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There's a guy on MTBR that has a front hub motor on a carbon fork. He got really pissed at me when I said that the combination seemed unsafe.
#18
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Unles you're running something big, like 500w, you're fine with a quality steel fork and no torque arms. 500w or more, I personally wouldn't put on the front, anyway. But the 250w/300w units are okay as long as you know the steel fork is in good condition.
#19
Senior Member
I have a 1500w (30 amp, 52V) front hub bike; steel fork, one torque arm, with a rear coaster brake, although I'll be adding a front cantilever soon. Great for road riding at 30 mph or so.
#20
Senior Member
I beg your pardon, you have a COASTER BRAKE? on an e-bike??? and you are "considering" a cantilever on the front, but you don't currently have anything stopping you and your motorcycle-size engine* except a coaster brake?
I hope you have good life insurance. That's honestly one of the more terrifying things I have ever read on here, or encountered in 7 years as a full time pro mechanic. There is absolutely nothing about this scenario which is remotely safe. That isn't a personal attack, it's a statement of fact.
Coaster brakes are not very strong in the first place; they are used on very low end bicycles, mainly kids' bikes. They are subject to overheating and failure at the kind of speeds you are describing - especially with the added mass of a motor, battery, and adult rider.
https://www.sheldonbrown.com/coaster-brakes.html
*In Alberta, a bicycle fitted with an electric motor of anything over 500W is legally a motorcycle and is subject to licensing and registration.