Tempted to DIY

[Andy Bluenoes]

Ive been e-biking for about 10 months now, and gone through 3 bikes. Anyone who has read some of my posts will see that its not quite been plain sailing.

Anyway, after learning quite a bit about how they work, and now I know a bit clearer what I need from the bike, I am thinking about building my own in a couple of months time.

Main things I need from the bike:
Range of 25 miles
Be able to do a steady 20mph with pedal assist. I would like to do the 20 mile trip to work in an hour and not be soaked in sweat when I get there.
Not be replacing parts every 2 months, or the electrics failing.

I will be doing around 120 miles a week, not sure of the exact route yet, as it will coincide with a house move.
My current bike is the cyclotricity stealth 1000watt with a 12ah battery.
I can comfortably do a 15 mile run to work with power set on legal mode, using the highest assist level, and it takes around 50 minutes. Thats over roads, cycle paths, and some pretty horrendous muddy towpaths.

If money was no object, I think given the mileage I do, something like a R&M cruiser would be perfect, but thats way too much at the moment.

So, my idea is to buy the most suitable bike using the C2W scheme up to £1000 that can be converted using something like the BBS02. I watched a video of how to install that, and Im pretty sure I could manage it.
There are different power levels available, not sure which one would do the job I need. And have no idea about what bike to use for the conversion.

If I did it this way, my hope is to get a quality bike that will easily meet my needs, and most of all, stand up to the mileage and potentially hard life it may have.

Good idea or not?

 

[Martyn979]

Ive been e-biking for about 10 months now, and gone through 3 bikes. Anyone who has read some of my posts will see that its not quite been plain sailing.

Anyway, after learning quite a bit about how they work, and now I know a bit clearer what I need from the bike, I am thinking about building my own in a couple of months time.

Main things I need from the bike:
Range of 25 miles
Be able to do a steady 20mph with pedal assist. I would like to do the 20 mile trip to work in an hour and not be soaked in sweat when I get there.
Not be replacing parts every 2 months, or the electrics failing.

I will be doing around 120 miles a week, not sure of the exact route yet, as it will coincide with a house move.
My current bike is the cyclotricity stealth 1000watt with a 12ah battery.
I can comfortably do a 15 mile run to work with power set on legal mode, using the highest assist level, and it takes around 50 minutes. Thats over roads, cycle paths, and some pretty horrendous muddy towpaths.

If money was no object, I think given the mileage I do, something like a R&M cruiser would be perfect, but thats way too much at the moment.

So, my idea is to buy the most suitable bike using the C2W scheme up to £1000 that can be converted using something like the BBS02. I watched a video of how to install that, and Im pretty sure I could manage it.
There are different power levels available, not sure which one would do the job I need. And have no idea about what bike to use for the conversion.

If I did it this way, my hope is to get a quality bike that will easily meet my needs, and most of all, stand up to the mileage and potentially hard life it may have.

Good idea or not?

Have you considered hub motors? A lot cheaper, usually more reliable and can be very efficient if you stay below 500W, the 250W ebay kits are just over £100 and they have 20mph top speed. Also its nice to have the motor seperate from the drive system in my opinion, regardless of what gear your in or whatever the motor is still doing its thing, predictability is good. Plenty of torque for hills too. Hobbyking have a sale on lipos at the moment also, i priced up a 4 cell 16ah and a 6 cell 16ah multistar combo (to make a 10S 16ah 36V pack) also for just over £100. So just over £200 you have a 16ah battery and a reliable motor. Not exactly sure in range but probably 40ish miles. Worth considering

 

[Andy Bluenoes]

Yes, thats something else to consider then

Just reading through the latest posts, it just seems the right way to go would be with a chain drive?

I like the idea of being able to change the tyre without all the excess weight of the motor.

Quite happy to go with over 250 watts if needed to get the speed I want, that side of things doesnt worry me.

 

[Martyn979]

Yes, thats something else to consider then

Just reading through the latest posts, it just seems the right way to go would be with a chain drive?

I like the idea of being able to change the tyre without all the excess weight of the motor.

Quite happy to go with over 250 watts if needed to get the speed I want, that side of things doesnt worry me.

Nothing wrong with chain drives, just more expensive, much more complicated mechanically which makes them less reliable, and potentially easier to overload without realising (throttling up in top gear from a standstill) Also fixing a flat on a hub motor is not as much of a problem as you might think, its awkward to change the tire yes but you only do that once a year maybe, repairing a flat can be done without loosening a single bolt, just take the tube out of the tire with the wheel on the bike, patch the flat and your done.

Slightly more awkward but its really not that bad, i have a 1000W rear motor with 2 torque arms (one either side) so its big awkward and heavy but it doesent really bother me because as i said you never really need to remove the wheel.

I also changed to the Kenda thorn resistant tubes recently (highly recommended by the way) so i had to take out my old tube from the motorised wheel obviously, it took about 5 minutes longer than it usually would have to swap out the tube. If you use zip ties on your motor power wire its literally as simple as cutting the ties so you can move the wire a bit, loosening the wheel nuts, sliding the old tube out while lifting one side of the axle then sliding the new tube in, replace the ties, tighten everything up and your done. But again you hardly ever have to replace tubes and tires. In my opinion this mild inconvenience is well worth the reliability and consistency of the little 250w motors, not to mention it would actually be legal on UK roads. Not that it matters to most of us lol

 

[Andy Bluenoes]

Cheers Martyn
Should have said my current ebike has rear 1000 watt motor so know where you are coming from.
Luckily I've not had a puncture in the last 9 months. ....Either down to sliming them or good luck!
I've just swapped to marathon tyres with Kevlar... Really don't want a rear puncture.
I've tried repairing in the past but could never get the patches to stick so just carry spare tubes now

Sent from my BUSH SPIRA D3 5 using Tapatalk

 

[Martyn979]

Cheers Martyn
Should have said my current ebike has rear 1000 watt motor so know where you are coming from.
Luckily I've not had a puncture in the last 9 months. ....Either down to sliming them or good luck!
I've just swapped to marathon tyres with Kevlar... Really don't want a rear puncture.
I've tried repairing in the past but could never get the patches to stick so just carry spare tubes now

Sent from my BUSH SPIRA D3 5 using Tapatalk

Get a decent repair kit, iv still got functionak spare tubes that are more patch than tube lol, keep them on my bike for emergency spares

 

[Deleted member 4366]

For commuting, I think a hub-motor would be much better. 20mph would be no problem if you use 48v. If you have a lot of stop-starts or hills, a geared one would be better, like the 500w Bafang CST, otherwise a DD would be OK.

You need to figure on about 20 WH per mile. IIUC, your ride to work is 20 miles, which means yo need a 40 mile range, in which case you'd need about 1000 WH to do the return journey, i.e. 48v 20 AH. There's plenty of reasonably priced triangle batteries of that size on Aliexpress.

Another thing to think about is a light-weight efficient bike, like a cyclocross one with straight handlebars - basically a road bike with disc brakes and straight bars. That would need less energy to maintain 20+ mph than an MTB, so you could probably do the return trip on 500 WH if you pedalled steadily. For that, you could also use a legal motor like a Bafang SWX02C at 48v and about 15 amps.

If you want to travel at 22mph, the motor needs to be about 280 rpm in a 26" wheel at the voltage you run it, so if its a 36v nominal one run at 48v, you need one about 220 rpm. If you get a motor that's too fast, you'll use a lot more battery without actually going faster.

Don't buy a new donor bike. that's a complete waste of money. A used one will cost half as much and be just as good.

 

[Woosh]

Just reading through the latest posts, it just seems the right way to go would be with a chain drive?

I can see from your earlier posts than your average speed is over 15mph.
In my experience, at less than 22mph, geared hub motors are difficult to beat, they give good torque, low energy consumption and low cost. However, all the geared hub motors are limited by the maximum RPM that the motor is built for. Beyond that maximum RPM, the motor does not assist. My SWX02 and BPM motors are wound for 234 RPM maximum.
Between 20-25mph, the BBS02 gives you flexible power, all the benefit of high torque and relatively low weight, good weight distribution but high cost.
At over 25mph, your existing 1000W kit is difficult to beat.
I would be tempted to save money, get a second hand high end bike and transfer the existing 1000W kit to it.

 

[Andy Bluenoes]

For commuting, I think a hub-motor would be much better. 20mph would be no problem if you use 48v. If you have a lot of stop-starts or hills, a geared one would be better, like the 500w Bafang CST, otherwise a DD would be OK.

You need to figure on about 20 WH per mile. IIUC, your ride to work is 20 miles, which means yo need a 40 mile range, in which case you'd need about 1000 WH to do the return journey, i.e. 48v 20 AH. There's plenty of reasonably priced triangle batteries of that size on Aliexpress.

Another thing to think about is a light-weight efficient bike, like a cyclocross one with straight handlebars - basically a road bike with disc brakes and straight bars. That would need less energy to maintain 20+ mph than an MTB, so you could probably do the return trip on 500 WH if you pedalled steadily. For that, you could also use a legal motor like a Bafang SWX02C at 48v and about 15 amps.

If you want to travel at 22mph, the motor needs to be about 280 rpm in a 26" wheel at the voltage you run it, so if its a 36v nominal one run at 48v, you need one about 220 rpm. If you get a motor that's too fast, you'll use a lot more battery without actually going faster.

Don't buy a new donor bike. that's a complete waste of money. A used one will cost half as much and be just as good.

Thanks for all the information D8veh....lots of googling to get my head round all that, given me plenty to think about

 

[Andy Bluenoes]

I can see from your earlier posts than your average speed is over 15mph.
In my experience, at less than 22mph, geared hub motors are difficult to beat, they give good torque, low energy consumption and low cost. However, all the geared hub motors are limited by the maximum RPM that the motor is built for. Beyond that maximum RPM, the motor does not assist. My SWX02 and BPM motors are wound for 234 RPM maximum.
Between 20-25mph, the BBS02 gives you flexible power, all the benefit of high torque and relatively low weight, good weight distribution but high cost.
At over 25mph, your existing 1000W kit is difficult to beat.
I would be tempted to save money, get a second hand high end bike and transfer the existing 1000W kit to it.

I can see from your earlier posts than your average speed is over 15mph.
In my experience, at less than 22mph, geared hub motors are difficult to beat, they give good torque, low energy consumption and low cost. However, all the geared hub motors are limited by the maximum RPM that the motor is built for. Beyond that maximum RPM, the motor does not assist. My SWX02 and BPM motors are wound for 234 RPM maximum.
Between 20-25mph, the BBS02 gives you flexible power, all the benefit of high torque and relatively low weight, good weight distribution but high cost.
At over 25mph, your existing 1000W kit is difficult to beat.
I would be tempted to save money, get a second hand high end bike and transfer the existing 1000W kit to it.

Thanks Woosh.
Im probably going to end up confusin myself over all these options!

I hadnt thought about that one. Mainly because I am doing 15 miles each way at the moment, running the bike in 250watt mode and it just gets me to work on mostly level 5.
So feel in a way, Im wasting the extra 750 watts....with hindsight it would have made more sense to get either the standard 250 w or 500 w stealth as they would be much lighter...the 1000 watt bike is a right heavy monster.

 

[Martyn979]

Check this out, good info

 

[Andy Bluenoes]

Thanks, its on my watch later list for when I get home

 

[RRC]

I'm a BIG Haibike fan. I'd never consider that buying components off the shelf, and putting them on a standard bicycle, to remotely come close in quality to what a team of engineers can design and test before putting it on the market.

 

[awol]

My SWX02 and BPM motors are wound for 234 RPM maximum.

Got any spare ones laid around? I can't seem to find a seller of this motor.

 

[Nealh]

234rpm quoted is the no load speed apply on road/riding load then then they are a 201rpm winding.

 

[Nealh]

Got any spare ones laid around? I can't seem to find a seller of this motor.

Elife bike sell a 48v cst.

 

[Woosh]

234rpm quoted is the no load speed apply on road/riding load then then they are a 201rpm winding.

they can support 234rpm* no pedaling but please don't translate it to wheel speed.

*with Big Bear 20A controller.

 

[Deleted member 4366]

Check this out, good info

Great find, Martyn. That's one of the best explanations I've seen. I give him 9/10. He missed the fact that you can get crank motors with throttles and the reason that the Haibike needs that extra idler is because of the high rear suspension pivot and/or to prevent chain suck problems.

 

[danielrlee]

I'm a BIG Haibike fan. I'd never consider that buying components off the shelf, and putting them on a standard bicycle, to remotely come close in quality to what a team of engineers can design and test before putting it on the market.

Nearly anybody can design and build a reliable low powered system. Your statement however couldn't be further from the truth. It is the hobbyists creating new and wonderful builds in their homes, sheds and garages that are really pushing the envelope of what's possible. I'd go as far as to say that most of the advancements that make it to the big name manufacturer's production lines, start as experiments by individuals who are members of forums such as this.

 

[Andy Bluenoes]

Check this out, good info

Just watched the video, very helpful thanks.
Have to think that a hub motor is best for my needs really.

Found this one too, all about direct drive or geared motors as a few people have mentioned them and it confused me!

Very helpful, so now I know what everyone means when they say mine is a direct drive!