custom 34lb(15kg) full carbon E-bike

[michael.kozera]

hi all.

just wanted to share my E-bike build with you guys. let me know any thoughts or criticisms about it.

please keep in mind that i had 3 main goals for this build:
1-stealth, i didnt want it to look like an E-bike, i wanted it to look and feel like a regular bike.
2-weight, i wanted it to weigh like a regular bike, again, goes back to #1
3-cost, kept this project under 4G Canadian (3g-USD at the time)

and i could add a 4th, it had to be fully dual purpose. as in i wanted to ride it to work on the street like a street bike, then hit the fire roads like a gravel bike, and lastly still have enough suspension to do light off-road rocky roads.

It's full Chinese carbon fiber parts:
-carbon frame
-29er's carbon rims (40mm wide)
-carbon de-railer
-carbon seat
-carbon crank
-carbon pedals
-carbon handle bar
-carbon stem
-carbon riser
-carbon bottle cage
-carbon seat clamp

as for the rest of the parts, its got aluminum/ titanium screws everywhere as i pretty much replaced every single screw with TI, with the expectation of a few parts that needed to be steel for the strength.

fox rear and manitou front. both covered with custom neoprene protectors.

11speed gearset, bottom 5 are steel/top 6 are aluminum. and lightweight chain.

bike has 130mm in the rear and 140mm in the front.

200mm front and rear with deore brakes

for the electric system its got a custom made motor (from china), i had it spec'ed for 52v nominal at 350Kv, i also had them build it in a smaller sized motor then they usually do so the motor is very small for its speed as you can see in the photos.

battery is custom internal battery i made using Samsung 3500mah cells, 56 of em for a total of 706wh pack

ESC is 52v/350w with no speed limiter of course.


bike weighed in at aprox 34lb(15kg), however as seen in the photo i added a few things for comfort:
- custom extra wide carbon Gel seat
- gel grips
- HD tubes (i absolutely HATE tubless.....)
- and some fairly fat 2.2 urban tires with some slight off road thread to em, since they are mounted on wide 40mm rims the 2.2 tire measures in at aprox 2.5"
-it had a carbon crank which broke so i replaced it with a IXF aluminum crank for now

this brought the weight up to apox 38lb(17kg), not bad IMO


the bike has a top speed of aprox 110km/hr down hill with the wind, pedaling cadence runs out at about 90km/hr tho........ so on flat ground i usually hit around 80km/hr average. without pedaling it goes around 50km/hr.


to make this project work i had to cut a hole in the frame at the bottom to slide in the pack and then mill out a mount for the ESC that would act like part of the frame structure once bolted back on, i also added cooling fins to this mount to keep the ESC nice and cool.

all internal wiring of course and no screen, only a throttle.

on/off button and charging port hidden under bottle cage


as most know, range varys greatly depending on what your doing. but this bike is very light and very efficient, on regular street riding i regularly get over 200km's while on the gravel roads ill get about 100km's then off road about 50km's..... so i would say aprox 120km's or range is fair?



ive put over 15,000km's on this bike in the last 12 months and the only issue i had was with the broken china crank.



i get very strange looks on the bike paths as you cant tell its an E-bike and the motor makes almost no noise at all haha

please let me know what you think?

 

[Gary]

Nice work.
Do you think the frame will hold up with the modifications you've done?
Did you have any way of testing its strength?
Also. How is the motor controlled? Is it torque sensing pedal assist or throttle controlled. Or some combination of the two?

 

[Gary]

Oh... And please also start a thread for your custom intense

 

[michael.kozera]

Oh... And please also start a thread for your custom intense

haha, ty, and yes that one is coming very soon.

Nice work.
Do you think the frame will hold up with the modifications you've done?
Did you have any way of testing its strength?
Also. How is the motor controlled? Is it torque sensing pedal assist or throttle controlled. Or some combination of the two?

ive ridden it over 15,000km's already, mostly street and gravel/dirt roads, but i have taken it off-road and off jumps abunch too. if i was to guess i would say aprox 1,000km's or offroad so far. the suspension is on the softer side for comfort, but it does have lock out.

as stated in the thread i originally had a china carbon crank, the crank broke when i took a 5ft jump in -25c and landed hard...... but the frame looks good, i dont see any cracks or dont hear any creeks.

the motor is controller via thumb throttle only. the reason being is i was not able to get a PAS working without adding a screen and i wanted this bike to be stealth soooo yeah. if you look on the handle bar on the left i made a custom thumb throttle lock to be able to lock the throttle in various positions. really handy on those flat long roads when your doing 70km/hr+

 

[ggx]

☢ ? Top work.

 

[Supratad]

That is astonishing, if those figures are correct. 50 Kph without pedalling is not an ebike though is it? Its an electric motorbike when used that way.
Any photos of the motor and battery on their own? It'd be nice to see just how small they both are, as from the pictures, it looks like any acoustic bike.
The cynic in me says there has to be a trade off somewhere, otherwise all the "big boys" would be selling bikes like this.

edit, hang on, motor is the rear hub yes? Not in the BB like I thought it was?

 

[Gary]

the motor is controller via thumb throttle only. the reason being is i was not able to get a PAS working without adding a screen and i wanted this bike to be stealth soooo yeah. if you look on the handle bar on the left i made a custom thumb throttle lock to be able to lock the throttle in various positions. really handy on those flat long roads when your doing 70km/hr+

Pretty cool. I'd like something similar but for a drop bar road/gravel bike. Off the shelf E road bikes are limited to 15mph here which is stupid.
I guess when you have the throttle switch off there's minimal drag in the hub so the bike could easily be ridden with no assistance too?
Also.. How does it feel last minute braking? I guess with your confirmation you need to flick the throttle down at the same time?
Haven't really looked into this sort of thing much. Thanks for sharing.

 

[michael.kozera]

That is astonishing, if those figures are correct. 50 Kph without pedaling is not an ebike though is it? Its an electric motorbike when used that way.
Any photos of the motor and battery on their own? It'd be nice to see just how small they both are, as from the pictures, it looks like any acoustic bike.
The cynic in me says there has to be a trade off somewhere, otherwise all the "big boys" would be selling bikes like this.

edit, hang on, motor is the rear hub yes? Not in the BB like I thought it was?

you should see my other bikes haha.

i might put of more photos later, perhaps a video. the battery in non-removable and its sealed inside the frame, and its a 3 piece battery.

the trade-off? i would say non-removable battery. the rear wheel is removable but very difficult to remove due to the hub. and no screen/PAS, but thats by design.

it funny, when i walk into a bike shop and see bikes going for 15-20G, as an engineer i sit there and laugh because there is no way a bike should cost that much. just because you added a motor does not make a bike 2x as expensive...... the electric components including the battery cost me less then 1g. but i guess i did have to build it all so there's that.

Pretty cool. I'd like something similar but for a drop bar road/gravel bike. Off the shelf E road bikes are limited to 15mph here which is stupid.
I guess when you have the throttle switch off there's minimal drag in the hub so the bike could easily be ridden with no assistance too?
Also.. How does it feel last minute braking? I guess with your confirmation you need to flick the throttle down at the same time?
Haven't really looked into this sort of thing much. Thanks for sharing.

one of the main reasons i build my own bikes/ build bikes for friends and family is because of the 25km/hr limiter...... like wtf. the bike has to assist to at least 40km/hr because most ppl can pedal to that speed. but im sure nanny state ppl have something to say about that....

yes, the HUB has minimal drag, in fact its got next to no drag, if i just free spin the rear wheel it spins for several minutes, as does the front wheel.

the throttle is spring loaded and will return to "0" when you let go, the power cuts off almost immediately.

 

[michael.kozera]

Looks great, but...

It has a rear hub motor, so it will be throttle controlled, or at best rudimentary cadence controlled, not torque sensing.
So I guess that would be a serious compromise in pedal feel, for some.

Where are the 706wh of batteries?
And the bike weighs in at 15kg including the 706wh of batteries?


If those 706wh of batteries are in the frame, and it weighs 15kg all in... top job

i ride motor bikes alot, so i like having a throttle haha.


the 706wh battery is in 3 pieces. the bulk of the battery is squeezed into the lower part of the frame tube (BB to head). the remaining 20 cells are in the top part of the tube. and the BMS is mounted ontop of the controller.

its a VERY tight fit, and no space for plugs even, everything is directly soldered.

 

[Gary]

Sounds like you know what you're doing here. Great stuff. A video would be great to watch if you get round to making one.

it funny, when i walk into a bike shop and see bikes going for 15-20G, as an engineer i sit there and laugh because there is no way a bike should cost that much. just because you added a motor does not make a bike 2x as expensive...... the electric components including the battery cost me less then 1g. but i guess i did have to build it all so there's that

Thing about bikes you can walk into a shop and buy is they have gone through tons of design processes before even being built nevermind all the various costs passed between design, component choice/acquisition, manufacture, marketing, assembly, distribution, shipping, taxes and the actual bike shop.
I wouldn't expect a guy like you to build something like you have here for a box of beer to any old stranger passing by with £3k in his hand. ?

 

[apac]

Nice build, is it a direct drive hub? otherwise I hope the geared hub and its axle hold out for you if you are jumping stuff. Internal hub gears take a hammering if you land while throttle is engaged. It's So cool to see DIY battery packs being put into down tubes.

 

[Jeffrey]

i get very strange looks on the bike paths as you cant tell its an E-bike and the motor makes almost no noise at all haha

Awesome build!
I thought the pictures were "before custom build". I didn't pay attention to the motor before reading the comments below.

What brand/type is the motor?

 

[Mcharza]

Awesome build!
I thought the pictures were "before custom build". I didn't pay attention to the motor before reading the comments below.

What brand/type is the motor?

I bet it's a bafang

 

[michael.kozera]

Nice build, is it a direct drive hub? otherwise I hope the geared hub and its axle hold out for you if you are jumping stuff. Internal hub gears take a hammering if you land while throttle is engaged. It's So cool to see DIY battery packs being put into down tubes.

it is not a direct drive. it is a plantery style hub motor.

i have the suspension set to more soft/comfort which should help with wear on the motor. i replaced the bearings in the motor already. took out the el-chepo bearings and put in some top tier bearings as ive had hub motor bearings fail before on various other builds.

i ride motorbike my entire life so im well experienced in not using the throttle when you land. cuz yeah. that would for sure break something.

 

[michael.kozera]

Awesome build!
I thought the pictures were "before custom build". I didn't pay attention to the motor before reading the comments below.

What brand/type is the motor?

haha, so i fooled you too. good, thats the entire point of the build. it looks and feels like a regular MTB, rides like one too.


motor is a CSC ( carbon speed cycles) off ebay.

 

[Mabman]

Nice bike there OP!

Pretty cool. I'd like something similar but for a drop bar road/gravel bike. Off the shelf E road bikes are limited to 15mph here which is stupid.
I guess when you have the throttle switch off there's minimal drag in the hub so the bike could easily be ridden with no assistance too?
Also.. How does it feel last minute braking? I guess with your confirmation you need to flick the throttle down at the same time?
Haven't really looked into this sort of thing much. Thanks for sharing.

That is exactly why I use a throttle on my e gravel bikes with no PAS and limiter crap. Don't have to go any faster than 50kmh but it is nice to have on tap, mainly I cruise around in lower to mid 40's.

I use front hub Direct Drive's also for the 2wd effect and have had 0 issues as most complain about, that have never ridden a front hub bike....I can set the watt output by holding the throttle for 2 secs at the desired amount and then let go. Blip the throttle to release or when I depress my regen button it also cuts power and it is the first thing I reach for when braking.

And @Kilham5:
so it will be throttle controlled, or at best rudimentary cadence controlled, not torque sensing.
So I guess that would be a serious compromise in pedal feel, for some.

To me there is a serious compromise in pedal feel on a PAS bike doing higher consistent cadence on the road. Eliminating it actually provides the same natural feeling you get on a non eBike and you can shift up and down easily as well without the extra tension on the drivetrain. However I do far prefer torque assist for my eMTB's.

 

[Gary]

That is exactly why I use a throttle on my e gravel bikes with no PAS and limiter crap. Don't have to go any faster than 50kmh but it is nice to have on tap, mainly I cruise around in lower to mid 40's.

I don't think it is.
I don't want to cruise around at 40. I just don't want the assistance to cut off before the speed I can pedal my normal road bike at.
Basically want a bike just as fast as my roadbike but less effort to do so so I'm not too sweaty when arriving at work
If I wanted a bike that does 50mph with no pedal assist I'd just buy a 125cc motorcycle. They're a lot cheaper than Ebikes.

 

[michael.kozera]

I don't think it is.
I don't want to cruise around at 40. I just don't want the assistance to cut off before the speed I can pedal my normal road bike at.
Basically want a bike just as fast as my roadbike but less effort to do so so I'm not too sweaty when arriving at work
If I wanted a bike that does 50mph with no pedal assist I'd just buy a 125cc motorcycle. They're a lot cheaper than Ebikes.

pretty much the exact reason i made this bike.

i dont want to be all gross and sweaty going to work, or to dinner, or meet a friend. on the way back tho, its open season and i hardly use any electrons, and i get a good work out on the way back.

its also nice that if we get too tired, or if you injure urself, u can always limb back using primarily E-power.

 

[Mabman]

I don't think it is.
I don't want to cruise around at 40. I just don't want the assistance to cut off before the speed I can pedal my normal road bike at.
Basically want a bike just as fast as my roadbike but less effort to do so so I'm not too sweaty when arriving at work
If I wanted a bike that does 50mph with no pedal assist I'd just buy a 125cc motorcycle. They're a lot cheaper than Ebikes.

That was meant to be 40kmh as I referenced 50kmh previously. So 22 to 24mph is my comfort zone for speed/range on the road which is beyond the 20mph limiter here in the US.

 

[Gary]

Isn't the assistance limit in certain US states 28mph by law on the road?
A far more sensible limit.

 

[EebStrider]

Do you make bikes for a living? If not, you should. ?

 

[Mabman]

Isn't the assistance limit in certain US states 28mph by law on the road?
A far more sensible limit.

Only in states that have adopted the Class laws put forth by the industry lobbying People for Bikes. My state, Oregon, hasn't yet and hopefully doesn't quite frankly. I might add that the limit for "Scooters" here is 25mph and that is what we are trying to get the state to adopt for eBikes instead of the Class laws.

However as my bikes will do 28mph pretty easily, especially because I have the gearing to be able to pedal effectively at that speed due to using Schlumpf high speed drives, the battery will still deplete pretty fast and it really isn't worth it on a bicycle with a 1hp motor.....I get way better wh/mi in the range I mentioned.

The Class 3 bikes I see out there don't even have enough gearing to pedal at 28 so I imagine they will zap a battery even faster because the motor is doing most of the work.

Also our Federal guidelines only go to 20mph so to me there is the possibility of liability if you are riding a Class 3 labeled bike and get into an accident going over 20? A worst case scenario that hasn't been tested yet to my knowledge.

 

[Jeffrey]

Hi Michael,

I'm planning to do a custom build based on yours using a Cube Stereo 150 SL actionteam ☺

I got yesterday the rear-wheel motor (also from CSC, but standard 36V 350W), the motor cover came with a freewheel thread.
Did you modify the motor cover to fit a cassette? Or directly get a motor cover compatible for cassette?

 

[michael.kozera]

Hi Michael,

I'm planning to do a custom build based on yours using a Cube Stereo 150 SL actionteam ☺

I got yesterday the rear-wheel motor (also from CSC, but standard 36V 350W), the motor cover came with a freewheel thread.
Did you modify the motor cover to fit a cassette? Or directly get a motor cover compatible for cassette?

i got a motor that was cassette compatible.

 

[Jeffrey]

i got a motor that was cassette compatible.

Thanks for the quick reply.
I will try to fit a shimano freehub from my spare parts to the motor cover, great challenge ?

 

[michael.kozera]

Thanks for the quick reply.
I will try to fit a shimano freehub from my spare parts to the motor cover, great challenge ?

dont bother. freehubs are crap.

just get a cassette motor. or find the part to swap out the freehub to a casette. youll thank me later haha

 

[Manc44]

Has this got a carbon or metal rear triangle?

What about a torque arm?

 

[michael.kozera]

Has this got a carbon or metal rear triangle?

What about a torque arm?

the bike is 100% carbon. the rear triangle is carbon with the aluminum insert for the hanger.

no TQ arm required becuase the ESC is only 350w ( about 800w burst/ 5 secs, and 400w continuous). not even close enough to require a TQ arm, a TQ arm is needed when you go 1000w or more.

 

[Manc44]

the bike is 100% carbon. the rear triangle is carbon with the aluminum insert for the hanger.

no TQ arm required becuase the ESC is only 350w ( about 800w burst/ 5 secs, and 400w continuous). not even close enough to require a TQ arm, a TQ arm is needed when you go 1000w or more.

I'm considering putting my 500W rear hub motor on my carbon frame.

If you've done 15,000Km on it and it's still OK, that says it all.

My motor puts out about 850W max and is rated at 45Nm. I was wondering what the forces must be on a rear disc brake, since it's stressing the chainstay and dropout in a very similar way, just the opposite direction. Braking has to amount to more torque than the 45Nm of my motor.

Then there's the axle nuts I do up at 35Nm each - so it would take 70Nm to loosen them anyway (in theory) and 45Nm is way under that.

 

[michael.kozera]

I'm considering putting my 500W rear hub motor on my carbon frame.

If you've done 15,000Km on it and it's still OK, that says it all.

My motor puts out about 850W max and is rated at 45Nm. I was wondering what the forces must be on a rear disc brake, since it's stressing the chainstay and dropout in a very similar way, just the opposite direction. Braking has to amount to more torque than the 45Nm of my motor.

Then there's the axle nuts I do up at 35Nm each - so it would take 70Nm to loosen them anyway (in theory) and 45Nm is way under that.

interesting,

the way i look at it it when you brake you are applying force through the rotor ---> then to the hub ---> then the spokes-----> then the rim/tire. the axle doesn't actually experience force apart from maybe side to side twisting force, as opposed to radial force ( 90 degrees opposite to side to side).

radial force is applied to the axale when accelerating because the force goes through the hub and into the frame somehow to push u forward. and thus a TQ arm will be needed i high radial force loads.

nothing wrong with using a tq arm, its just extra safety for ur frame.

BTW, i did use these, i guess you can call "mini" tq arms cuz they kinda do the same thing and they mount on the axle/frame.