Hi - I have a few questions about what to choose?

goral

Pedelecer
Jan 20, 2024
56
3
I have a few questions about what to choose?
Mid motor or front wheel?
750W or 1000W?
20Ah battery - on the frame or on the rack?
I'm hoping someone who knows both this and this system can explain to me which will be better - thanks.
 

thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,209
371
oxon
What bike is undergoing the conversion, and whats the expectation in terms of range weight carried and terrain/conditions.

Generally rear wheel hub drives are preferred over the front since more weight is focused on the rear hence added traction where powerful front hubs could just spin on the spot.

Bike balance is a prime consideration for battery placement but many bikes leave few options.

Lots of folk in here with vastly more info than me but clarifying the bike and needs will get you the best answers.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,814
3,152
Telford
I have a few questions about what to choose?
Mid motor or front wheel?
750W or 1000W?
20Ah battery - on the frame or on the rack?
I'm hoping someone who knows both this and this system can explain to me which will be better - thanks.
Generally, a front wheel motor is a bad idea, but it depends on the bike. You certainly can't fit a 750w or 1000w motor into standard MTB forks. You need heavy duty rigid steel forks for that.
 

goral

Pedelecer
Jan 20, 2024
56
3
Hi thanks for reply.
This will be an older (10 years old) mid-price, urban-type bike.
29in wheels, derailleurs.
I want to bring it back to life, for myself as a curiosity - everyone writes that conversion to e-bike gives new life not only to the bike but also to the user:)
Generally as an everyday bike - work - shopping - pleasure.
I'm looking for something in the 750-1000W range as I feel it will catch me ;)
I've enjoyed cycling since I was a kid, but my current state of physical condition limits me a bit.
By the way, what do you guys think of the mid hub (Bafang)?
Thanks.

ps.
Terrain, predominantly paths, tarmac, concrete pavement rather than grass or other typical off road use -Not that type of bike..
 
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cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,639
770
Beds & Norfolk
I'm looking for something in the 750-1000W range as I feel it will catch me ;)
You just don't need 750/1000w for that kind of riding. Apart from the legalities of being caught on public pavements/roads, seizure/penalty points on your licence, even a fully legal geared 250w motor will propel you beyond the legal assisted 15.5mph limit if that's what you're winking about.
 

thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,209
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oxon
Fwiw im not small, under 100kg just,, and the 250w rear hub motor on the bike pictured in my profile pic ( a £200 ortler) rolls up hills near me with nominal input from myself, and on the flat i can if i choose ghost pedal and roll along at 15mph which is pretty much the limit im happy with relying on rim brakes to stop.
..

a geared 750w motor could carry you upto 30mph and beyond with a suitable (and expensive) battery at which point i think everyone would rather not rely on old style rim brakes, and if your bike has no mount points for disk brakes i would definatley not consider a motor rated that high.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,814
3,152
Telford
Hi thanks for reply.
This will be an older (10 years old) mid-price, urban-type bike.
29in wheels, derailleurs.
I want to bring it back to life, for myself as a curiosity - everyone writes that conversion to e-bike gives new life not only to the bike but also to the user:)
Generally as an everyday bike - work - shopping - pleasure.
I'm looking for something in the 750-1000W range as I feel it will catch me ;)
I've enjoyed cycling since I was a kid, but my current state of physical condition limits me a bit.
By the way, what do you guys think of the mid hub (Bafang)?
Thanks.

ps.
Terrain, predominantly paths, tarmac, concrete pavement rather than grass or other typical off road use -Not that type of bike..
It would be best to give us exact details of the bike you intend to convert because there are lots of ifs and buts.
 
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RollingChunder

Pedelecer
Dec 7, 2023
96
36
Hi thanks for reply.
This will be an older (10 years old) mid-price, urban-type bike.
29in wheels, derailleurs.
I want to bring it back to life, for myself as a curiosity - everyone writes that conversion to e-bike gives new life not only to the bike but also to the user:)
Generally as an everyday bike - work - shopping - pleasure.
I'm looking for something in the 750-1000W range as I feel it will catch me ;)
I've enjoyed cycling since I was a kid, but my current state of physical condition limits me a bit.
By the way, what do you guys think of the mid hub (Bafang)?
Thanks.

ps.
Terrain, predominantly paths, tarmac, concrete pavement rather than grass or other typical off road use -Not that type of bike..
Picture of bike please.
 

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
2,590
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Do not get caught up in big numbers. High wattage motors are generally direct drive, good at high speed on the flat, crap at climbing hills and highly inefficient at low speed or stop/start riding. This means they are battery eaters.
Motors only consume what they are fed by the controller. To get 1Kw of input power (at 36v) would need a 28A controller. In order to supply this the battery would have to be able to supply 40A to avoid voltage sag and battery damage. Mega expensive.
And, because the motor is rated at 1Kw, the bike would be ilegal.

We can point you to very capable 250w rated geared hub motors that coupled to the right controller and battery will give in the region of 800w peak. That would be on maximum setting and wouldn't be used all the time. Battery will be cheaper (though any 20Ah battery is going to cost) and system will be legal if pegged to 25Kph.

I recently removed a direct drive motor from a bike I was working on. In it's wheel it weighed a little over 8Kg. Its replacement legal motor was a little under 4Kg in its wheel. A massive difference to the braking energy needed.
If the bike you wish to convert cannot accomodate disc brakes, I think I'd look elsewhere.

For reliability and a more relaxed riding experience, I would go for rear hub. Personal choice.
 
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Peter.Bridge

Esteemed Pedelecer
Apr 19, 2023
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584
1) The balance of the bike is better with the battery mounted on the downtube. I have both - don't really notice it when I am riding but when I am pushing / carrying / putting away - the rear rack battery is more awkward to manoeuvre. Better to go with a larger battery if you can afford it - as well as better range they are more powerful for longer portion of your journey and will tend to last longer.
2) It's worth getting a bike that will be easy to convert rather than start with a bike and then consider converting it - so disc brakes (and convert to hydraulic if mechanical) and room for downtube battery for starters.
3) The Bafang mid drives are very good and powerful but you need to concentrate when riding to keep in the right gear (since the motor power goes through the drivetrain) and the gear change can be a bit clunky when using the higher power settings (particularly changing down gears up a hill) and using the 11 tooth cog. For really steep off road hill climbing there is an advantage for the motor power to go through the gears.
4) For road / light trail use I prefer a rear hub motor with torque sensor. It is very relaxing to ride and if you stop / slow down in the wrong gear, then a dab on the pedals will kick the motor in to help you start off. The motor power isn't going through the chain drive train so it doesn't matter what gear you are in.
5) Be a bit wary - a 750W rated motor isn't 3 times as powerful as one rated 250W. The most important thing is the controller power. For example there are kits with 250W rated motors that have 48V 15A controllers that are quite powerful. If choosing a hub drive, think about the max speed of the motor and the power band. A hub drive that can propel you at over 30 mph won't be in it's peak power band at 6mph up a steep hill. The same motor with a higher winding will have a lower top speed but more powerful at 6mph up a steep hill.
 
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goral

Pedelecer
Jan 20, 2024
56
3
So, however, a rear wheel motor is better than a mid hub?
Another question about wheel size, because I am a little confused.
I have 3 dimensions for my wheel.
1. tyre dimension, on me 69 cm ~27"17
2. the dimension taken from the top of the frame, at my place 62cm ~24"41
3. the dimension taken from the lower edge of the frame, at me 59cm ~23"22
And from tyre on picture.
Which one should I take into account if I decide to go with a motor in a wheel?
As you can see from the picture, the space for a downtube battery is unlikely to be there, and it will definitely be 20Ah.
I'm planning long distance trips.

56028


56029

This is a temporary bike, the target bike will be something between a mountain bike and a road bike. I don't know what category it will. I am currently in the phase of looking for a second-hand, cheap bike.
That's why I don't want to drill or change the structural integrity of this temporary one.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,814
3,152
Telford
So, however, a rear wheel motor is better than a mid hub?
Another question about wheel size, because I am a little confused.
I have 3 dimensions for my wheel.
1. tyre dimension, on me 69 cm ~27"17
2. the dimension taken from the top of the frame, at my place 62cm ~24"41
3. the dimension taken from the lower edge of the frame, at me 59cm ~23"22
And from tyre on picture.
Which one should I take into account if I decide to go with a motor in a wheel?
As you can see from the picture, the space for a downtube battery is unlikely to be there, and it will definitely be 20Ah.
I'm planning long distance trips.

View attachment 56028


View attachment 56029

This is a temporary bike, the target bike will be something between a mountain bike and a road bike. I don't know what category it will. I am currently in the phase of looking for a second-hand, cheap bike.
That's why I don't want to drill or change the structural integrity of this temporary one.
You can forget fitting a 750w or 1000w motor to that bike. It has crappy rim brakes that are hardly adequate for it without a motor. What people don't realise is that your average speed increases when you have a motor. A pedal bike averages about 8 - 10 mph. When you fit a 250w motor, it goes up to about 14 mph, which means you have on average twice as much kinetic energy, so you'd have to add an extra set of brakes to each wheel to get the same braking as you had before. If you fitted a 1000w motor and averaged 20 mph, you'd need 4 times the braking, and for 30 mph, 9 times the braking. For any motor you need disc brakes unless you fit a very lightweight, low power kit and only ride slow.

For a step through bike like that, a front motor can work as long as it's fairly low power, and you can fit a rack battery. A rear motor with rack battery is sort of OK, but it makes the bike a bit unbalanced when getting it out of the shed and pushing it around. A low-powered crank motor would also work with a rack battery, but as I said above, best is to forget that bike and find a better donor. The donor needs disc brakes and a triangle frame with plenty of room for the battery. You don't need fancy gears, wheels or anything else when you fit a motor, so no need to buy anything expensive. Cable disc brakes can be easily swapped out for hydraulic ones in a few minutes and don't cost too much.

Your wheels are probably 700C, which should be written on the tyre somewhere.
 
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thelarkbox

Esteemed Pedelecer
Aug 23, 2023
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Had similar wheel size queries when shopping for my conversion kit but i can spot a clear 700x35 stamped on the tyre ;) thats 700mm x 35mm .

+1 to everything @saneagle says above. since fitting the rear wheel kit this summer Ive already replaced the brake blocks and my white/cream tyres are stained black from the worn rubber blocks. And when returning from tesco with a full load in the panniers and boxes the extra braking distance when rolling along at 15mph is significant and needs taking into consideration.

from my perspective as a lazy bloke with a bike and not a sports cyclist, a bafang mid drive would be a pita requiring me to physically keep up with the required pedaling speed or loose motor power.. while with my hub motor i can just keep the pedals moving to trick the pas sensor into thinking im cycling (ghost pedaling)
and relax while the motor does all the work for a bit ;)

Also anythig other than a smooth cycle track or perfectly even road surface 15mph on my bike is HARD on the backside, pre ebike i woud cycle slower now i cycle 10-12mph with motor assist and only open to 15mph when i dont risk loosing all the box contents carried when rolling over a 1 inch deep pot hole.
 
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Az.

Esteemed Pedelecer
Apr 27, 2022
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Plymouth
from my perspective as a lazy bloke with a bike and not a sports cyclist, a bafang mid drive would be a pita requiring me to physically keep up with the required pedaling speed or loose motor power.. while with my hub motor i can just keep the pedals moving to trick the pas sensor into thinking im cycling (ghost pedaling)
and relax while the motor does all the work for a bit ;)
Nah... Bafang motors are for lazy people. Still can ghost pedal or use throttle. You probably had Tongsheng motors with torque sensors in mind.
 

goral

Pedelecer
Jan 20, 2024
56
3
There is no problem at all changing to disc brakes at front wheel if necessary.
On the current ones, it brakes without a problem, going from a gradient of 30% over 20mph - tested.

Nah... Bafang motors are for lazy people. Still can ghost pedal or use throttle. You probably had Tongsheng motors with torque sensors in mind.
In your opinion, is it worth fitting a mid hub or is a rear wheel better?
I've looked through the various options and I'm confused.
Whether mid hub or front wheel, rear wheel.
The cost of conversion is very similar, with mid hub being the most expensive.
I would therefore like to buy once and not have problems, and then change something else and go into further expense.
Or is it not possible and you have to practice it yourself?
Personally, I am now considering the mid hub or the rear wheel. Changing gears does not scare me:)
I live in an area where there are a lot of uphill climbs.
The mid hub (in the photos) is not noticeable.
 

thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,209
371
oxon
Nah... Bafang motors are for lazy people. Still can ghost pedal or use throttle. You probably had Tongsheng motors with torque sensors in mind.
Thanks for the correction, I have No experience with the mid drives and above is based on what i have read only and misinterpreted apparently ;)

? but with the drive via the chain ring are the pedals not revolving at stupid rpm at full throttle? take your feet off and loose one trying to catch the pedals again?
I thought the Tongsheng tdz drives had a pawl and freewheeling chain ring?

sorry for the interruption OP now i AM confused .
 
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Az.

Esteemed Pedelecer
Apr 27, 2022
2,045
903
Plymouth
In your opinion, is it worth fitting a mid hub or is a rear wheel better?
In my opinion none is better they are just different.
I would suggest mid drive for off-road and hub drives for roads.

Front hub is the easiest to install. It should be fine on your bike, but rear will be fine too.
 

goral

Pedelecer
Jan 20, 2024
56
3
Had similar wheel size queries when shopping for my conversion kit but i can spot a clear 700x35 stamped on the tyre ;) thats 700mm x 35mm .
Is same as 28"?
from my perspective as a lazy bloke with a bike and not a sports cyclist, a bafang mid drive would be a pita requiring me to physically keep up with the required pedaling speed or loose motor power.. while with my hub motor i can just keep the pedals moving to trick the pas sensor into thinking im cycling (ghost pedaling)
and relax while the motor does all the work for a bit ;)
What motor and battery do you have?
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,814
3,152
Telford
There is no problem at all changing to disc brakes at front wheel if necessary.
On the current ones, it brakes without a problem, going from a gradient of 30% over 20mph - tested.



In your opinion, is it worth fitting a mid hub or is a rear wheel better?
I've looked through the various options and I'm confused.
Whether mid hub or front wheel, rear wheel.
The cost of conversion is very similar, with mid hub being the most expensive.
I would therefore like to buy once and not have problems, and then change something else and go into further expense.
Or is it not possible and you have to practice it yourself?
Personally, I am now considering the mid hub or the rear wheel. Changing gears does not scare me:)
I live in an area where there are a lot of uphill climbs.
The mid hub (in the photos) is not noticeable.
The main decision point between hub and crank drive is whether you're going to do any serious off-road riding, where the more centalised mass of the crank drive makes the bike more agile. The crank drives give the advantage of very high torque at low speed in bottom gear, so you can climb very steep hills. They can also give some advantage for towing. For normal riding on the road, crank drives have mainly disadvantages. If you choose your system carefully, there is no hill on a road that a legal hub-motor cannot manage. Hub motor gives a better ride, is more reliable, more durable, cheaper to run and cheaper to buy. The crank motors, for most bikes, are a little easier to install. The overall differences aren't massive, so it's not too much to get hung up on. Many people are happily commuting on their BBS01/2s. I think hub motors do it better.

You might think that your brakes are OK now, but when you convert to ebike, you'll change your mind. Considering that you can get a much more suitable donor bike for less than £100, it's not worth putting any effort into that bone-shaker.
 
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