Changing from hub motor to mid drive

Captain Nick

Finding my (electric) wheels
Feb 27, 2023
7
3
Hi all, I'm considering changing my DIY e-bike from a 1000W hub motor to a 500W Bafang mid drive. My intention is to de-rate the motor in the programming so it is legal to use on the road. What is the Bafang like to ride when the PAS etc is properly set up, specifically with 250W/25kph limit?

Thanks
Nick
 
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jimriley

Esteemed Pedelecer
Jun 17, 2020
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Why not go the other way, fit a completely legal 250w bbs01b, it certainly copes with ordinary roads etc and can have the speed limit raised from the control panel. Maybe 25mph dependent on hearing. The motor can be tweaked to 350w using a connecting lead and a laptop or via speeed app on an android phone. Only in the grounds of your family estate obviously.
I have a hybrid set up like that and it copes with steep and rough local bridleways etc admirably, I changed the chainring from a 46t to a 42t to get up steep.tracks better. Check out the thread about getting the throttle legalised, that certainly wouldn't be possible with a non legal motor.
 
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Nealh

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Aug 7, 2014
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It doesn't matter what you do, in the eyes of the law 500w is illegal and that is the motors rating no matter what you do to the settings.

Simply tweaking and playing with settings makes no difference if the motors rating needs to be prooved.
 

Zlatan

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Nov 26, 2016
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Hi all, I'm considering changing my DIY e-bike from a 1000W hub motor to a 500W Bafang mid drive. My intention is to de-rate the motor in the programming so it is legal to use on the road. What is the Bafang like to ride when the PAS etc is properly set up, specifically with 250W/25kph limit?

Thanks
Nick
Don't know about the 500w Bafang but I fitted a (in theory) 250w one to a Cube mtb about 18 months ago for daughter. (it's marked 250 w) and it's absolutely fine.
I do think the crank drives cope better than hubbs on the 250 w limit. I don't think the Bafang feels quite as powerful as my Haibike but there's hardly anything in it. There are no hills in Peak District I would avoid using it.
To be honest, and I don't want to upset all those folk with hub drives, but I strongly suspect once anyone tries a Crank drive they will never go back to hub,and I suspect even more so if limited to 250w..(I have never found the 250w limit on crank drive restrictive, or disappointing. Quite the reverse to be fair. Mine still surprises me how good it climbs..)
And just to reinforce what folk are saying. Even if you restrict motor to 250w in settings if it's capable (or marked) of offering over 250w (continuous) it's illegal.
If you have it tho, fit it. If you haven't buy a 250..I suspect they are same anyway. Daughter's has made a great bike with a brilliant range.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,139
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For day to day use a hub is the more relaxing option to ride and is my errand commuting choice, the mid drive has it's merits and is my choice for my cargo bike towing. A propriety mid drive is a different beast to a mid drive kit.

Before covid my go to ride bike was hub simply for reliability.

Most fair weather riders will have a mid drive because simply the proprietary brands have gone that way because of the revenue they can charge and the anti consumer repair option.
 

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
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Just to add fuel to the fire it should be pointed out many legal pre-built proprietary ebikes are 250W in Europe but in other markets the same motors are sold as 350W or more and they don't even seem to restrict the wattage and can go over 700W for some motors but do always meet the 15.5mph assisted speed restriction for 250W rated models. From what I've seen some Chinese manufacturers and US/EU importer brands are learning about how EU manufacturers manipulate their certification to claim 250W and now we are seeing models with so called 250W motors which look extremely similar to their much higher rated models even matching them for peak torque or close to it. Again though they are keeping to the 15.5mph limit.
 

Captain Nick

Finding my (electric) wheels
Feb 27, 2023
7
3
Why not go the other way, fit a completely legal 250w bbs01b, it certainly copes with ordinary roads etc and can have the speed limit raised from the control panel. Maybe 25mph dependent on hearing. The motor can be tweaked to 350w using a connecting lead and a laptop or via speeed app on an android phone. Only in the grounds of your family estate obviously.
I have a hybrid set up like that and it copes with steep and rough local bridleways etc admirably, I changed the chainring from a 46t to a 42t to get up steep.tracks better. Check out the thread about getting the throttle legalised, that certainly wouldn't be possible with a non legal motor.
I was interested in the BBS02b because there is a 48V version of this and my bike is already set up to 48V. I don't want to go to 36V as it means buying a new battery etc. Plus I read that the motor controller etc is stronger on the BBS02 so it's less likely to blow up. I think the throttle behaviour can also be programmed - I'm quite happy for it to only work up to 6km/h, that's enough to get you moving which is all I use mine for now anyway.
 
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Captain Nick

Finding my (electric) wheels
Feb 27, 2023
7
3
You really sure its legal to use a motor above the 250W limit, on the road, just by making adjustments to the controller ?
I don't see why not, the Bosch and Shimano motors used on the pre-built e-bikes are capable of far more than 250W but they are de-rated in software. Those can be up-rated by plugging in a simple box, which you could do out on the road quite easily. The Bafang needs a laptop connected which is not really plausible while you're out and about. It's not exactly like there is a switch on the side of the motor you can flick to get 1000W
 

Captain Nick

Finding my (electric) wheels
Feb 27, 2023
7
3
For day to day use a hub is the more relaxing option to ride and is my errand commuting choice, the mid drive has it's merits and is my choice for my cargo bike towing. A propriety mid drive is a different beast to a mid drive kit.

Before covid my go to ride bike was hub simply for reliability.

Most fair weather riders will have a mid drive because simply the proprietary brands have gone that way because of the revenue they can charge and the anti consumer repair option.
One of the things I hate most about the hub motor is the fact that it's virtually impossible to repair a puncture in the rear tyre out on the road. The wheel is tethered to the bike by the motor cable and there obviously isn't a quick release. There's no way I would be able to change an inner tube away from home, and it's only a matter of time before I need to.
 

Captain Nick

Finding my (electric) wheels
Feb 27, 2023
7
3
Just to add fuel to the fire it should be pointed out many legal pre-built proprietary ebikes are 250W in Europe but in other markets the same motors are sold as 350W or more and they don't even seem to restrict the wattage and can go over 700W for some motors but do always meet the 15.5mph assisted speed restriction for 250W rated models. From what I've seen some Chinese manufacturers and US/EU importer brands are learning about how EU manufacturers manipulate their certification to claim 250W and now we are seeing models with so called 250W motors which look extremely similar to their much higher rated models even matching them for peak torque or close to it. Again though they are keeping to the 15.5mph limit.
I think Bosch use the same motors in their 250W/25kph e-bikes as in their 45kph speed pedelecs, just with a software change obviously to raise the cut-off speed. I don't see why a 500W Bafang will be different, I will remove any labels and put some of my own on stating the voltage, nominal output power and cut-off speed. These will be honest too - I'll set them in the software. I'm really not sure what lengths the rozzers will go to to prove it's an illegal bike...if they just ride it themselves they'll see on the display it's only kicking out 250W, and it cuts off at 25kph.
 

soundwave

Esteemed Pedelecer
May 23, 2015
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dongles dont give you any more power it just removes the speed limit but the bosch controllers are 20amps as thats what gets you up the hills.

under 15.5mph the motors can pull 8-900w climbing a hill but will cut off over 15mph limit.
 
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Captain Nick

Finding my (electric) wheels
Feb 27, 2023
7
3
dongles dont give you any more power it just removes the speed limit but the bosch controllers are 20amps as thats what gets you up the hills.

under 15.5mph the motors can pull 8-900w climbing a hill but will cut off over 15mph limit.
If I set the current limit on the Bafang to limit it to 250W will it be a hard limit or will it still draw more when it's under heavy load?
 

soundwave

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May 23, 2015
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it does not matter what you set it at as it still wont be road legal.

the fact that you can get in to the controllers settings and change stuff means it has a off road mode or switch where as on my bosch bike there is no way at all to change anything like that and why i had to get a rip off dongle as it is the only way to remove the speed limit or just rip out the controller and use a vesc or phase runner controller.

my m8 has been blasting to work in all weather for the last 2 years on his hd and has never been stopped same as me there just not interested and if you go on just eat and get some food delivered it will be on a 1000w+ hub drive bike. :p
 

Sturmey

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Jan 26, 2018
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One of the things I hate most about the hub motor is the fact that it's virtually impossible to repair a puncture in the rear tyre out on the road. The wheel is tethered to the bike by the motor cable and there obviously isn't a quick release. There's no way I would be able to change an inner tube away from home, and it's only a matter of time before I need to.
Carry a double ended tube as a spare. (and a small scissors/knife to cut off the old tube). Then no need to take off the wheel.
50492
 
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StuartsProjects

Esteemed Pedelecer
May 9, 2021
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One of the things I hate most about the hub motor is the fact that it's virtually impossible to repair a puncture in the rear tyre out on the road.
Most of the hub motors I have seen, including the 3 I have bought, have a short cable coming out of the hub which plugs into the extension cable going to the controller.

Removing a wheel with a hub motor is easy enough, I just unplug the cable by the motor.
 

jimriley

Esteemed Pedelecer
Jun 17, 2020
562
384
If I set the current limit on the Bafang to limit it to 250W will it be a hard limit or will it still draw more when it's under heavy load?
The 250w rating isn't a fixed limit, afaik a "250w" rated motor can be pushing 500w at times. There was also a comment that you'd need to carry a laptop to tweak your motor to 350w while out and about in the grounds of your mansion, no, the Android Speeed App works great, using the same cable. I know it isn't legal on the road, on the other hand, while officer Dibble might be a traffic cop with power to decide, he can check your speed limit readily, but not the internal motor settings. All he can see is that the motor is stamped 250w and appears legal. Afaik an ordinary plod isn't competent to rule on traffic related matters.
 
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esuark

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Jul 23, 2019
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kent
Carry a double ended tube as a spare. (and a small scissors/knife to cut off the old tube). Then no need to take off the wheel.
View attachment 50492
I had a rear wheel hub motor puncture a couple of weeks ago and still had a normal tube fitted. So wrapped the normal tube around the chain stays and fitted a Gaadi (I have two). Took the normal tube off when I got home.