Single speed - Ebike ( fixie style ) mid drive

[extrasilver]

hey

i was i'm currently in the middle of converting my my single speed bike to electric, about 25minutes ago i thought i may as well post the project on an online forum as there doesn't seem to be too many people converting a bike like this .. literally in the past 15 minutes iv just been i've just snapped a snapped a few pictures of my bike showing where i'm up to so far.

any questions or comments along the way i will try to answer

so, heres a shop bought bike i picked up from a local store here in Germany.
its an SE draft lite.. its only cost around 240 euro new but i do think it will make a for a good conversion of my my own spec.. and not mentioning the cost of upwards to 2000+ euro for a purpose built one.

https://ibb.co/iBXO6Q
https://ibb.co/kDSC0k

the motor i bought is a Q100H 350w nominal geared hub.. it was tricky trying to find a motor that would like with a rear drop out width of only 120mm.. i fighured as this motor has a removable collar spacer so i can modify it for use with a 120mm setup pretty easily

https://ibb.co/mnofmQ
https://ibb.co/hcULmQ

my chain was due to be replaced soon and i heard that a 415 motorcycle chain can work with BMX's and single speed bikes.. as i work for a motorcycle wholesale supplier i had access to getting hold of one at a very cheap price, so i thought it was worth the cost to find out if they really do fit?

https://ibb.co/eUsjD5
https://ibb.co/nozxY5

here is a simple tool i made out of nut's, bolts and washers.. it's so i can spread out the rear drop outs if needed.. turns out i didn't really need it as the washers on the axel do straighten the drop outs if they have become untrue a little

https://ibb.co/mB1N0k
https://ibb.co/dJ2jD5

here is the how the motor will be installed.. i may find better fitting washers soon to tidy things up a little.

https://ibb.co/dg9mRQ
https://ibb.co/fJYD6Q
https://ibb.co/jTnvLk
https://ibb.co/jcw0mQ
https://ibb.co/nkCHY5

here is the crank with the 415H chain, i just testing the fitment between here. it seems fine so far.
https://ibb.co/gVOPD5
https://ibb.co/eUKWt5
https://ibb.co/ijXUfk

the wheel that i think i will having the hub mounted in.. im toying with the idea to purchase better and lighter wheels at some point tho.

https://ibb.co/c6oPD5

for next month, im planning on getting a hidden controller mounted and the wheel laced

UPDATE

- ended up canceling lacing the hub due to the 5 week wait.. settled for a mid drive instead

 

[extrasilver]

 

[extrasilver]

 

[extrasilver]

Hey guys, its been a long time but i finally put an e-bike together!

long story short with the hub motor. i gave a bike shop 5 weeks to lace the wheel with the hub but when i finally came to collect it, it wasn't ready so i decided to cancel the job and picked up a mid drive system in which i could easily install myself at home..

i picked up a TSDZ2 350w system from BMS battery for around 420 euro's after postage and import duties to Germany. link below

https://bmsbattery.com/home/803-sdz2-torque-sensor-central-motor.html

i was a little worried that a mid drive system wont really like to work with a single speed bike such as this, but it proved me wrong. 36Kph top speed is good for me and awesome at climbing hills! only downside is that on the flat straights the motor will cut off once you reach the top speed due the motors maximum speed not being able to keep up, although i can just about pedel faster myself ( its a lower RPM mid drive system than most on the market ) .. i will fix this problem soon once the DC to DC boost converter arrives, the converter will boost my 36v battery up to 49 volts with up to 20 amps at the input, hopefully it will give the motors RPM so i'm able to reach 40+ Kph.. the controllers speed limit of 25Kph has been disabled by the way

i desperately need to purchase some better non-painted wheels and purchase the brake system mentioned above! the stock brakes just can't keep up.

any questions, just ask

i've posted a picture of the bike below and a little above

 

[extrasilver]

hmm, i was expecting more comments than this x)

 

[D C]

hmm, i was expecting more comments than this x)

I'm sure you'll get plenty of response if you need help or advice
You have two likes all ready and I'll give you another one.
Stick around, it's a friendly forum
Dave.

 

[Benjahmin]

How's it working out with the mid drive on a single speed bike? As I understand it you need gears to keep the motor at the right revs and to prevent it from stalling. Unless you live in the flatlands

 

[extrasilver]

How's it working out with the mid drive on a single speed bike? As I understand it you need gears to keep the motor at the right revs and to prevent it from stalling. Unless you live in the flatlands

Hi Benjahmin

i had the same concern myself when purchasing the kit but after installing and trying it, i had absolutely nothing to worry about after all.. the performance is amazing.

i can climb and accelerate up steep hills with minimal input from myself very easily.. it literally drags me up hills! without the motor bogging down at all.. and with the stock gearing of 44/16t ( standard single speed gearing ) it also gets brings me to a top speed of 38Kph in under 4 seconds

the problem im having now is that i really need a 13-14 tooth freewheel at the rear because when i reach my top speed of 38kph the motor simply cuts off due the very small amount of pressure i'm applying to the pedals at the higher cadence speeds ( torque sensing system ).. i believe the motor is more than capable of getting me up to 50+ Kph with the correct gearing..

the TSDZ350 mid drive system has different gearing setup compared to the BBS01/02

the TSDZ350 has an internal gearing of approximately 45:1.. the motor spins at speeds up to 4000 Rpm while the crank will max out between 80-100 rpm <- i can peddle faster that the motor can turn it.. this results in having much much better low-mid end torque

i believe the BBS02 system can turn the crank up to around 160-200 rpm, much faster than a human can pedal.

the TSDZ350 system is perfectly suited for single speed bikes

im currently looking to purchase a 48v controller as a replacement to the current 36v one.. and to use the thumb throttle that can be purchaed sepreatly i'm hoping this will allow me to reach 45-50Kph

 

[extrasilver]

easy way to view it

bafang BBS01/02 - drives like a petrol engine
higher RPM and power at mid-top end

TSDZ350 - drives like a diesel engine
lots of power and torque at low-mid range, not so much at the higher rpm's
( bringing the voltage up from 36 to 48v should solve this )

 

[KTM Bike Industries UK]

hmm, i was expecting more comments than this x)

You've posted about what is essentially a motorbike (in the UK) on a UK pedelec forum, so this isn't really the place to show off your illegal bike. Sorry.

 

[anotherkiwi]

Correction: it is a moped. And yes there is a forum subject for that on here too

 

[extrasilver]

You've posted about what is essentially a motorbike (in the UK) on a UK pedelec forum, so this isn't really the place to show off your illegal bike. Sorry.

technically its not an illegal bike, can be limited to 250watts and speed limited to 25Kph.. just the display allows me to remove the restrictions by holding both buttons down at start up..

i just have an road and 'off-road' option if you will.

 

[KTM Bike Industries UK]

technically its not an illegal bike, can be limited to 250watts and speed limited to 25Kph.. just the display allows me to remove the restrictions by holding both buttons down at start up..

i just have an road and 'off-road' option if you will.

Yes, which in the UK, makes it illegal.

 

[extrasilver]

Yes, which in the UK, makes it illegal.

wellllll...sue me for not living between the lines

 

[anotherkiwi]

What we are saying is that you posted in the wrong subject. You could have posted in http://www.pedelecs.co.uk/forum/forums/speed-pedelecs-s-pedelecs-non-eapcs-overseas.43/ and the above comments would not have been made.

Oh and you can replace UK by EU still (at least until 2019) mode change switching is illegal in the EU.

wellllll...sue me for not living between the lines

Many of us ride or have ridden bikes capable of over 25 km/h but we are polite about it...

 

[KTM Bike Industries UK]

Just helping you understand, because clearly you thought the "switch" made it legal, which it doesn't. Now you know you're riding a motorbike hopefully you'll be a bit more aware of what laws you're breaking, especially as you work in the motorcycle industry. But if you're breaking the law anyway, I don't see why you don't just ride a motorbike? But its your choice, just realise you are posting in a pedelec site, not a motorbike site.

 

[extrasilver]

Just helping you understand, because clearly you thought the "switch" made it legal, which it doesn't. Now you know you're riding a motorbike hopefully you'll be a bit more aware of what laws you're breaking, especially as you work in the motorcycle industry. But if you're breaking the law anyway, I don't see why you don't just ride a motorbike? But its your choice, just realise you are posting in a pedelec site, not a motorbike site.

its all good, the smiley face at the end was just to make it clear i wasn't being serious

 

[extrasilver]

Ooo KTM, i have a friend in the design team over at Kiska ( i'm sure you know them ), i know of so many secret projects happening within the company .. i'm not aloud to say anything tho

the new Bosh drive system they are working on seems pretty cool tho! i asked my friend to tell the software designer to make some kind of flaw in the system so we can easily remove the speed & power restrictions.. i'm pretty sure it wont happen tho, but it was worth a shot

 

[extrasilver]

What we are saying is that you posted in the wrong subject. You could have posted in http://www.pedelecs.co.uk/forum/forums/speed-pedelecs-s-pedelecs-non-eapcs-overseas.43/ and the above comments would not have been made.

Oh and you can replace UK by EU still (at least until 2019) mode change switching is illegal in the EU.



Many of us ride or have ridden bikes capable of over 25 km/h but we are polite about it...

its all good, the smiley face at the end was just to make it clear i wasn't being serious

 

[xander02]

hmm, i was expecting more comments than this x)

Hi extrasilver. I think this build is absolutely fantastic. Great job!!

I was also thinking of installing a rear hub on my single speed but after seeing your build you have convinced me to go with a mid drive . It basically means I won't have to get new rims threaded etc and I think it will hopefully look more stealthy.

Couple of questions:

What battery do you use? I'm thinking of getting a 36v 10.5A bottle battery attached to my downtube. I have seen some online that look like water bottles which will hopefully add to the stealthy look. I've only got a 16km round trip commute so hopefully this battery will be fine.

I currently have a 47/17 set up on my single speed. I would like to try and use the same ratio with this middrive and I'm a little worried the gearing is a bit high and the motor may struggle to get off the mark and cause damage. Does your motor struggle when you start up with your 44/16 ratio?

Have you been tampered to install a throttle too?

Thanks