fixie/single speed electric bike build

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

sorry for the poor lighting

Cool project! I'll follow along!

my plan is to have a very small 600w motor controller below the crank hidden away as much as possible.. as controlling the power im just going to rather have a twist throttle or either a thumb throttle..no LCD or brakes with cut-off switches.. im trying to keep it as tidy looking and stealth as possible .

for the battery, i will be keeping it in a backpack and simply have a cable with leading to the seat post.

currently looking at running 52v 15 amps max at the moment

Looking forward to see how this finishes up.
Looking to kit up my commuter at some point.

I always like different kind of projects, so good luck with it! May I ask the reason behind it?

How much would a battery like that weigh?

Q )I always like different kind of projects, so good luck with it! May I ask the reason behind it?

A) hey thank you! :) reason behind it is mainly due me to simply having an interest in electric vehicles and wanting to build something for a while now. i originally thought of converting a car but the cost would of been wayyy to high.. 2nd though was a motorcycle but i don't have a bike licence.. so i ended up with the idea of converting a bicycle.. much cheaper and simpler :)

Q) How much would a battery like that weigh?

A) my planned battery setup is to use 2x 7 cell li-po batterys from hobbyking wired in series

should leave me with a 52 volt 5.8 Amph battery weighing in at around 1.9 Kg, 300 watt/h pack

my journey to work is only around 5 minutes, supermarket 2 minutes, train station 1 minute away from home so i don't need a large battery for long distance 20+ miles for example :)

off to the bike shop to have the wheel laced up :)

should have an update in the next couple of days

ok so... my local bike shop completely declined the job of lacing the hub.. as he only speaks German its hard for me to translate.. the only thing i believe i managed to pick up was that the spokes will be too short for the wheel to work :S

can anybody shine some light on why the bike store rather aggressively declined the job?

700c wheel, 30mm deep dish, the spoke count on the ehub and stock rim are the same so i'm not sure why they claim it cant be done? i've also seen this exact hub motor used with fordable bikes with very small wheels before without issue.

hmm

I would guess they might just not want the risk. Presumably there is the potential for far more force to be transmitted from the hub to the rim, when it is under power, and the shop might just not want to be seen as being responsible for any issues that might occur.

I'd also look into the law at this point. I know in the UK eBikes have to be limited to 15 mph and 250w motor, and beyond that it counts as a motor vehicle with all that entails

i like your thinking branwen.. you may be right here..

i have another bike store in the town which is a 1 man business.. he's a younger guy ( mid 20's like myself ) and i find the younger generation here speak English just fine.. at least i will be able to speak with him and explain that i'm happy to take full responsibility if the wheel brakes or anything bad happens.

I thought a lot about this idea myself.. It makes a lot more sense than an ebike with gears. Most electric cars have only one gear. Good luck.

What was the motivation for swapping to a motorbike chain?

A guess here but with a larger diameter hub flange and deeper section rim, while that shortens the spokes, it also moves the angle that the spokes leave the rim further away from 90 degrees. The angle at the hub flange is ok because the spokes pivot. But as the nipples at the rim are (usually) designed to be at 90 degrees, you end up bending the spoke. If you bend the threaded part it is even more likely to break.

In reality, you might be ok. Modern spokes are way over engineered and if the threads are rolled rather than cut, there is even less chance of a break.

I would just go for the beefiest spokes I could and just crack on. Like you say, it's your bike and your risk. It is unlikely to suddenly explode and it's worth giving it a go.

@lasyrabbit
i really like the minimalist look of a single speed and after riding one for 8+ months now my legs have definitely settled in to it.. i think that if i can gear the bike correctly it could work really well.. the motor could help me at lower speeds to get going. and i can help the motor at higher speeds.. that's the plan anyway! :)

@o̼wlz͛
Hi Owlz.. 70% of the reason why is because i work for motorcycle wholesale parts supplier so the chain cost me less than a cup of coffee, i read online somewhere that a 415 chain will fit.. i wouldn't say i can prove it yet tho!

10% i think it kinda looks cool

20% i really needed a new chain anyway.

keep in mind that this project is kinda of an experiment :)

Interesting project. A pal of mine built up a SS commuter e-bike using a pompetamine frame and a bionix rear wheel. The concept worked really well apart from the bionix motor breaking down three times and him finally giving up on all the warranty claims hassle.

ah awesome!.. well apart from the warranty claims that is.. seems like a nice system, but i'd never pay the 2300+ euro price tag!.. my hub motor only cost me 82 dollars directly from china.

i managed to stretch out the drop outs last night.. 120mm to 135mm
now i'm already looking at upgrading the motor to a MAC t10 xD

if i buy this motor, i wont be running it at 76v and 55 amps.. maybe 60v 20-30amps myself but the video gives you an idea of what this MAC motor can really do

https://www.youtube.com/watch?v=UD_K_TRGcs4

120mm to 135! That's quite a distance, got a pic of the frame?

Hi MCamb, i'm currently in work at the moment but i take take a snip when i'm home and upload it for you.. the motor i have is fitting much better now.

• having a drop out of 135mm opens up a whole other world of motors to choose from
  

small update
the rear wheel and motor are currently in the shop being laced up
and i've just placed an order for some upgraded brakes :D :D

i bought a pair of Magura HS33 R Urban Hydraulic Rim Brake's

1 Attachment

Cool, what switch/throttle are you going for? What with the nature of SS riding, a on/off switch would be awkward no?

Oh and will you need special brake levers that have a cut off built in?