metanewbie
100 W
Yep. That's one of my major concerns about mid-drive.
Hill Climbing Assistance
- Thread starter metanewbie
- Start date
molybdenum
1 kW
There are a variety of motor options, all with advantages and disadvantages. Most on this forum are interested in riding fairly high powered ebikes > 1000W and in some cases, in the multi KW range. Few here have real life experience building and riding setups aimed at minimal assistance for a fit rider, but will definitely be aware of most motor options available. As power is increased, so does complexity and wear and tear. Conversely, an under-powered system can overheat on hills, but only if the rider does not provide substantial assistance. The graphs above show an efficiency curve at different speeds. The reason why small motors overheat on hills is because they are being operated at lower speeds where the motor is much less efficient and all the watts provided to the motor end up being dumped as waste heat. In my experience, a fit rider could take advantage of a smaller motor for hill assistance and keep it happy by not bogging it down on hills. You'd have to be mindful and make sure to keep a minimum speed on hills to avoid stressing the motor, or ease off the throttle and rely on the lower gears of the bike and leg power.
Friction drives are cheap, low power requirements. Excess tire wear might be a concern, and I don't see them being discussed much on this forum. Hence, there isn't a whole lot of collective real life experiences with these friction drives and members here won't have practical advice to help guide you with troubleshooting, or even choosing the best system for your needs. Most would probably cog and increase pedaling resistance if connected to the tire, but would easily be disconnected after serving their purpose on a hill climb. Looking at the available options, it does look like the technology has improved over the years and there are some potentially interesting choices to explore.
Mid-drive motors are great climbers owing to being able to run them through your cassette gears. They require some ongoing tuning to keep them aligned with the gears and they greatly increase wear and tear on drivetrain components such as cassettes and chains. This would be an OK option for someone who is mechanically inclined with lots of bike maintenance experience, but might increase expenses long term if commuting significant distances on a daily basis owing to component wear and increased maintenance costs. They can be pedaled without cogging, and would feel much like riding a normal bike when unpowered.
Geared hubmotors are in themselves great climbers and can be purchased with slower winds which have much slower top speed but much greater hillclimbing torque. Most have a clutch and do not cog or increase pedaling resistance when unpowered, so will feel like riding a normal bike without power. It is possible to purchase tiny <200W hubmotors or multi KW monsters, and in a variety of motor gear ratios from fast to torquey. The nylon gears are fragile and prone to melting if the motor is overheated. That being said, they can last several years and several thousand km if treated nicely. Overheating can be avoided by a fit rider who only wants a bit of extra push on hills. Keeping a bike at a minimum speed of 10-15 kph depending on motor winding, and avoiding bogging it down will prevent damage.
Direct drive hubmotors are not geared, tend to be larger, heavier and more noticeable on the bike, and will cog and increase pedaling resistance when unpowered. They are the most robust, as they contain magnets and do not have moving parts such as internal gears. They can be good hillclimbers if you choose one with slow windings that will increase torque at expense of top speed. Members on this forum have a lot of experience with these, as they are real workhorses and ideal for higher powered builds. They are still prone to overheating, which will often cook the hall sensors first, but in extreme cases, will fry the motor windings or wiring.
It is more challenging to purchase a quality system that suits a fit rider wanting minimal assistance, as most want a higher power setup and these sell better. Still, there are options out there for those requiring minimal assistance, mostly due to European ebike power restrictions of 200-250W assistance, which create/maintain a market for lower power motors.
I have some pretty steep hills in my mountainous region, and am a fit rider who is only interested in a bit of extra power to speed a lengthy work commute. I use a ~500W geared hubmotor (similar to SX2) which is vastly underpowered for these steep hills and would die in minutes if not aided by pedaling. It still works great after several years of commuting 30km+/day because I pedal hard, and keep the motor in the happy zone. If I didn't have steep hills, I'd have probably opted for an even smaller geared motor.
Regardless of your motor choice, I'll be following this thread as it seems like our ebike needs are similar.
Friction drives are cheap, low power requirements. Excess tire wear might be a concern, and I don't see them being discussed much on this forum. Hence, there isn't a whole lot of collective real life experiences with these friction drives and members here won't have practical advice to help guide you with troubleshooting, or even choosing the best system for your needs. Most would probably cog and increase pedaling resistance if connected to the tire, but would easily be disconnected after serving their purpose on a hill climb. Looking at the available options, it does look like the technology has improved over the years and there are some potentially interesting choices to explore.
Mid-drive motors are great climbers owing to being able to run them through your cassette gears. They require some ongoing tuning to keep them aligned with the gears and they greatly increase wear and tear on drivetrain components such as cassettes and chains. This would be an OK option for someone who is mechanically inclined with lots of bike maintenance experience, but might increase expenses long term if commuting significant distances on a daily basis owing to component wear and increased maintenance costs. They can be pedaled without cogging, and would feel much like riding a normal bike when unpowered.
Geared hubmotors are in themselves great climbers and can be purchased with slower winds which have much slower top speed but much greater hillclimbing torque. Most have a clutch and do not cog or increase pedaling resistance when unpowered, so will feel like riding a normal bike without power. It is possible to purchase tiny <200W hubmotors or multi KW monsters, and in a variety of motor gear ratios from fast to torquey. The nylon gears are fragile and prone to melting if the motor is overheated. That being said, they can last several years and several thousand km if treated nicely. Overheating can be avoided by a fit rider who only wants a bit of extra push on hills. Keeping a bike at a minimum speed of 10-15 kph depending on motor winding, and avoiding bogging it down will prevent damage.
Direct drive hubmotors are not geared, tend to be larger, heavier and more noticeable on the bike, and will cog and increase pedaling resistance when unpowered. They are the most robust, as they contain magnets and do not have moving parts such as internal gears. They can be good hillclimbers if you choose one with slow windings that will increase torque at expense of top speed. Members on this forum have a lot of experience with these, as they are real workhorses and ideal for higher powered builds. They are still prone to overheating, which will often cook the hall sensors first, but in extreme cases, will fry the motor windings or wiring.
It is more challenging to purchase a quality system that suits a fit rider wanting minimal assistance, as most want a higher power setup and these sell better. Still, there are options out there for those requiring minimal assistance, mostly due to European ebike power restrictions of 200-250W assistance, which create/maintain a market for lower power motors.
I have some pretty steep hills in my mountainous region, and am a fit rider who is only interested in a bit of extra power to speed a lengthy work commute. I use a ~500W geared hubmotor (similar to SX2) which is vastly underpowered for these steep hills and would die in minutes if not aided by pedaling. It still works great after several years of commuting 30km+/day because I pedal hard, and keep the motor in the happy zone. If I didn't have steep hills, I'd have probably opted for an even smaller geared motor.
Regardless of your motor choice, I'll be following this thread as it seems like our ebike needs are similar.
docw009
1 MW
How about experiences with the Kepler friction drive developed by a forum member in Australia? A number of members bought it. You had to supply your own motor controller and battery, and maybe the motor, but I think total cost was still less than what above the kits cost.
I was interested as I already had controllers and batteries laying around. but in those days, I could get a hub motor kit for under $200. I believe I can still them from China for under $300 today.
I was interested as I already had controllers and batteries laying around. but in those days, I could get a hub motor kit for under $200. I believe I can still them from China for under $300 today.
Chalo
100 TW
If that kind of system were used, the motor unit could be duplicated on both bikes, with the battery and controller in a swappable bag or box.
That could be the case for hub motor systems as well.
Motor $300
TSDZ8 tongsheng Mid Drive Motor Kit 750W 500W 250W electric bicycle Conversion Engine with torque sensor for ebike
TSDZ8 tongsheng Mid Drive Motor Kit 750W 500W 250W electric bicycle Conversion Engine with torque sensor for ebike
48V 15Ah Samsung battery $200, but OOS in USA now.
Electric bicycle ebike Battery Hailong G70 G56 21700 18650 Cells Pack 48V 36V 17.5AH 15AH 20AH 13AH Bicycle Lithium ebike Battery Lithium fits1000W
Electric bicycle ebike Battery Hailong G70 G56 21700 18650 Cells Pack 48V 36V 17.5AH 15AH 20AH 13AH Bicycle Lithium ebike Battery Lithium fits1000W
Here's what concerns me about the qiroll:
..that's extremely high gearing for a 320w motor on 700c wheels. I'm concerned with that thing burning up on your mega hillclimb.
Coincidentally this would be perfect for the bike with 16" wheels.
AZ: True, i personally wouldn't recommend any batteries with unnamed Chinese cells though, which are not known for being the safest. I'm kinda shocked to see the TSDZ8 going for so cheap!
..that's extremely high gearing for a 320w motor on 700c wheels. I'm concerned with that thing burning up on your mega hillclimb.
Coincidentally this would be perfect for the bike with 16" wheels.
AZ: True, i personally wouldn't recommend any batteries with unnamed Chinese cells though, which are not known for being the safest. I'm kinda shocked to see the TSDZ8 going for so cheap!
Neither would I, that is why I linked battery with Samsung cells (SAMSUNG INR21700-50GB).
Me too, especially so quickly after it was released. I paid much more at the beginning of the year, but I paid extra for road legal one with 250W label. I don't regret, happy others can buy it cheap.
metanewbie
100 W
That is my personal issue. I would greatly prefer something that can mechanically disconnect anytime I wish. The motor would only be helpful for hills because I spend my recreational riding miles around flat areas near the beaches. Only the ride home is very hilly.
It seems only the friction drives are capable of such disconnections, but would they assist on hills? I expect to pedal a lot, which is fine, but it would be helpful not to be dead tired at home on arrival each time. Even if it means going faster or with less energy drain, it would help a lot.
I think I'm in good shape, but I'm also in my early 50s, so my youthful energy no longer exists, especially after a long day at work. (Sorry, I'm ranting.)
So, for the moment, let’s assume I should try friction drive.
For your information, I have an Amazon Prime account, which has an incredible return policy, but I don't plan to exploit that on purpose.
Here are some feasible friction drive solutions I’ve come across (I’m open to other suggestions):
QR-E PRO +H70 Battery Kit – Ebike Conversion Kit-Qiroll - $439 (with proprietary voltage battery. Bidirectional with regen braking. Good tech support with replacement parts, requires occasional replacing a tape strip which can be purchased as 3M floor grip anywhere. Quick release attachment available for easy swap between bicycles.)
QR-E MUTE-Plus +B70*1 200Wh Ebike Kit (same as above, but lower watts with proprietary battery.) Non bidirectional. No regenerative braking. Lower battery capacity than Pro. Quick release attachment available.)
QR-E M-Flex Motor Kit – Ebike Conversion Kit-Qiroll $198.00 (requires a separate battery, same as the previous for other details like not bidirectional and no regenerative braking, but any size 36v battery can be used, quick release attachment available etc.)
With Qiroll devices above, is it better to get the pro with the regen and proprietary voltage or something like the flex and purchase separate batteries?
Amazon Prime Generic ‘Candidate 1) $259 (not many reviews but they like it. It requires 48 v battery, can mechanically disengage via throttle, no apparent company, support, or replacement parts.)
Amazon Prime Generic ‘Candidate 2’ $155 (the least expensive, requires 48 v battery. Not sure how clutch throttle works. Seller demonstrates 100% waterproof in videos. Replacement roller wheels available for purchase. Appears to use a quick release attachment for easy swapping.)
They do, but they don't have batteries in USA warehouse now. Worth to keep an eye on or drop them an email as price is very good IMO.
metanewbie
100 W
So the 16” is a better candidate for friction drive? Good to know. I actually have identical Advent drive trains on both bicycles but different chainring sizes because of the wheel sizes. The gearing is very close so they feel similar when I ride them.
metanewbie
100 W
That's a good point!
metanewbie
100 W
Ha! Yes I've been down that rabbit hole with a bafang mid drive em3ev battery and all the fancy stuff. I wasn't happy with it. Felt like a ball and chain most of the time because I didn't need it. So I'm hoping to come up with a very light solution, if possible.
metanewbie
100 W
I wouldn't consider friction system at all, so I can't offer advice on that. I just said to avoid proprietary systems as in long term it will cost you a fortune.
Here would be my top pick for geared hub motor if cheap and light are the highest priorities.
Q100H 36V350W Rear Driving EBike Hub Motor RPM 201
- Very cheap
- Dual reduction, so high very torque per lb; same density advantage as mid drive.
- 201RPM winding should go slow enough that it won't overheat on hills.
- Sad 82% efficiency on the flat but you're just using it for hills?
- 4.6lbs
- Downside: requires threaded freewheel, limits your maximum gears to 8 speeds.
- Freewheels better than a friction drive.
Advantages over friction drive:
- Better supported, many companies making these motors have been in business for decades
- Doesn't consume tires constantly
- 1000's - 10000's of miles without maintenance if not abused
- Power delivery doesn't slip in rain/dirt/etc
I don't know if you'll get help here on friction drives, they're probably the least popular of all drive types, but good luck, maybe someone here knows something about them.
Q100H 36V350W Rear Driving EBike Hub Motor RPM 201
- Very cheap
- Dual reduction, so high very torque per lb; same density advantage as mid drive.
- 201RPM winding should go slow enough that it won't overheat on hills.
- Sad 82% efficiency on the flat but you're just using it for hills?
- 4.6lbs
- Downside: requires threaded freewheel, limits your maximum gears to 8 speeds.
- Freewheels better than a friction drive.
Advantages over friction drive:
- Better supported, many companies making these motors have been in business for decades
- Doesn't consume tires constantly
- 1000's - 10000's of miles without maintenance if not abused
- Power delivery doesn't slip in rain/dirt/etc
I don't know if you'll get help here on friction drives, they're probably the least popular of all drive types, but good luck, maybe someone here knows something about them.
metanewbie
100 W
I'm super open to all ideas and options including ingesting loads of spinach like Popeye!
metanewbie
100 W
Is there a way to get that as a kit? And is there a close 9-speed cassette-compatible cousin?
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,268
Q100C CST 36V350W Rear Driving EBike Hub Motor RPM 201
Q100C CST 36V350W Rear Driving V-brake, rim-brake, Disc-Brake compatible E-Bike Hub Motor.
P.S. Is the rear spacing on your Jamis Coda Comp 135mm or 130mm?
Last edited:
metanewbie
100 W
Thanks! I wish they sold their hubs as kits too.Q100C CST 36V350W Rear Driving EBike Hub Motor RPM 201
Q100C CST 36V350W Rear Driving V-brake, rim-brake, Disc-Brake compatible E-Bike Hub Motor.bmsbattery.com
P.S. Is the rear spacing on your Jamis Coda comp 135mm or 130mm?
metanewbie
100 W
Q100C CST 36V350W Rear Driving EBike Hub Motor RPM 201
Q100C CST 36V350W Rear Driving V-brake, rim-brake, Disc-Brake compatible E-Bike Hub Motor.
P.S. Is the rear spacing on your Jamis Coda Comp 135mm or 130mm?
Good question! Unfortunately I’m not sure. It’s a 2012 Jamis Coda Comp but I’m not sure if that helps.Q100C CST 36V350W Rear Driving EBike Hub Motor RPM 201
Q100C CST 36V350W Rear Driving V-brake, rim-brake, Disc-Brake compatible E-Bike Hub Motor.
P.S. Is the rear spacing on your Jamis Coda Comp 135mm or 130mm?
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,268
Jamis Coda Comp (2012) Specs
View product specifications: Jamis Coda Comp 2012 - View Reviews, Specifications, Prices, Comparisons and Local Bike Shops.
www.bikeroar.com
Shimano 2200 rear hub...that would be 130mm.
I think you are overcomplicating simple things. A little like you want to eat cake and have it. E-bikes are different than bikes. Don't fight it... embrace it.
If I were you I would buy used hybrid on Ebay or Facebook and convert it with small rear hub motor + medium battery with good cells. You want to arrive at work rested and fresh. That is what e-bikes are for.
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