Built Emtb from scratch - Kirby Bikes

[StuckintheSpokes]

Haven’t seen it on the forums, so thought I’d share.

 

[R120]

Funnily I saw this earlier as it popped up in my you tube feed - I kinda respect the guy for what he has done, but that bike would be an utter pig to try and ride aggressively on proper trails, geo all wrong, weight distribution all wrong, and the Bafang software is no where near as advanced a the Shimano/Bosch/Brose equivalents, which far more than power output are what make the motor feel natural rather than on/off in terms of assistance.

 

[All Mountain Coaching]

Same, turned up in my feed too. Turned it off after a few minutes, hardly ultimate Emtb.

 

[Mark S]

I'm not sure I have any other choice but to build my own. I also have a friend who has a programmable engine controller which he thinks he can get to work on Bafang.
Because of an injury to me knee which stopped me cycling over 10 years ago, I’m told by the medical specialists that I should not put any strain on my knee if I do cycle. Without a motor I could only cycle on the flat at a steady cadence.

So on very steep hills I think I will need: (i) a throttle, and (ii) a motor a little stronger than 250 watts ... unless someone has info to the contrary. A throttle is not permitted for road use and is unlikely to be needed as there are no very steep hills with roads anywhere near me. But I will need it for off-roading.

The need for a stronger motor with an option for a throttle, severely limits my purchase options, and I am thus looking to build my own eMTB bike. The two frames I have found are both designed for a Bafang M600 (500watts, 120Nm, about 3.6kg {the 250 watt M500 looks virtually identical and fits the same frames}). They are Dengfu (M09 BAFANG_dengfubikes 11), and a frame by Xiamen Yishun Carbon Composite Technology company Ltd, (New Enduro Full Suspension Ebike Frameset With Bafang Engine E1075 Suppliers,Manufacturers,Factories). They have different frame geometries, and after some research I need some advice about geometry (for another post). I have not been able to find other options than these two frames but if anyone can suggest another frame, or a different course of action, I'd be only too pleased to look at it.
Cheers
Mark

 

[ccrdave]

Funnily I saw this earlier as it popped up in my you tube feed - I kinda respect the guy for what he has done, but that bike would be an utter pig to try and ride aggressively on proper trails, geo all wrong, weight distribution all wrong, and the Bafang software is no where near as advanced a the Shimano/Bosch/Brose equivalents, which far more than power output are what make the motor feel natural rather than on/off in terms of assistance.

where did you see the geometry figures, i have been looking at these frames on ali baba but cant find any geo
I talked to the bafang guys at the Birmingham bike show and I thought their software was pretty good and quite customisable

 

[Marke]

I love this bike. For me this is the most exciting innovation i have seen in the 2 years or so I have owned an emtb and been following ebike news. Far more so than a few hundred grams shaved off motor weight or a few extra cells in a battery.

The idea of being able to source your own battery, motor and frame and put it together yourself is (IMHO) the direction the sport should be moving in. It will introduce competition which will mean better products at lower prices - sorely needed.

I'm a fan of high power motors - this type of system would allow for 1 frame with multiple motors for different circumstances (closed course or on road). It would enable me to build and develop my own batteries and tune motors and controllers. It is my opinion that tuning is not a dirty word and actually a very good thing. It could make for some great racing.

 

[ccrdave]

where did you see the geometry figures, i have been looking at these frames on ali baba but cant find any geo
I talked to the bafang guys at the Birmingham bike show and I thought their software was pretty good and quite customisable

ignore that I found the geo, your right not enough reach too long chainstays for 27.5 wheels

 

[Mark S]

where did you see the geometry figures, i have been looking at these frames on ali baba but cant find any geo
I talked to the bafang guys at the Birmingham bike show and I thought their software was pretty good and quite customisable

Try this New Enduro Full Suspension Ebike Frameset With Bafang Engine E1075 Suppliers,Manufacturers,Factories
and M09 BAFANG_dengfubikes 11
Cheers
Mark

 

[Mark S]

Try this New Enduro Full Suspension Ebike Frameset With Bafang Engine E1075 Suppliers,Manufacturers,Factories
and M09 BAFANG_dengfubikes 11
Cheers
Mark

Oh, I pasted the links but the WWW address was replaced by a link. Suggest you should each into Google

 

[Mark S]

Oh, I pasted the links but the WWW address was replaced by a link. Suggest you should each into Google

ignore that I found the geo, your right not enough reach too long chainstays for 27.5 wheels

Can fit 29ers to each ... I think that is expected

 

[craig landau]

so what did the bike cost to build and what was the total weight ,

 

[StuckintheSpokes]

so what did the bike cost to build and what was the total weight ,

Well it was a one-off with the spec, but you can find links in the description to a full build as well as what you need to convert:

YouTube

YouTube

 

[dirt huffer]

He built the exact bike he wanted. Props to him. I bet he will enjoy that bike more, considering the hard work he put into figuring it all out. Anyone with a credit card can go out and buy a prebuilt bike, but to build one is cool, even if it's not something someone else would ride

 

[paquo]

So on very steep hills I think I will need: (i) a throttle, and (ii) a motor a little stronger than 250 watts ... unless someone has info to the contrary.

have you tried out any of the current generation of bikes? Turbo and first gear and you can almost coast up hills

 

[R120]

There are plenty of off the shelf frames out there that you can buy direct from China, I have looked at doing it quite a few times but most have odd or conservative geometry that are not what I am looking for.

I would have no problem going down this route for a general/commuting bike, but for a performance EMTB (and by that I mean handling not power) there just isn’t a great self build option with an off the shelf frame out there right now, unless you get a frame builder to build you one, or go down the Light Carbon OEM mould frame route.

When I looked at it, there was just no way you could make it economically stack up against the likes of a Vitus, Canyon or Commencal, as buying all the individual bits separately to a good spec cost more than a new bike from them, so unless you just buy a frame and swap everything over it doesn’t work out.

I believe he built the bike for 5k, which is a grand more than a VItus E-Sommett VR

 

[Marke]

There are plenty of off the shelf frames out there that you can buy direct from China, I have looked at doing it quite a few times but most have odd or conservative geometry that are not what I am looking for.

I would have no problem going down this route for a general/commuting bike, but for a performance EMTB (and by that I mean handling not power) there just isn’t a great self build option with an off the shelf frame out there right now, unless you get a frame builder to build you one, or go down the Light Carbon OEM mould frame route.

When I looked at it, there was just no way you could make it economically stack up against the likes of a Vitus, Canyon or Commencal, as buying all the individual bits separately to a good spec cost more than a new bike from them, so unless you just buy a frame and swap everything over it doesn’t work out.

I believe he built the bike for 5k, which is a grand more than a VItus E-Sommett VR

 

[MattyB]

I commented against the video that the geometry was outdated for trail/enduro use. His response...

"Frame is not dated, just because it doesn’t have an integrated tube battery. It means you can fit over 1kWh of energy storage if you are using it to commute etc."

It's time for an official...

 

[Mark S]

have you tried out any of the current generation of bikes? Turbo and first gear and you can almost coast up hills

I’m going to try a couple at least. Do you know if the mag Brose Specialised has this feature?

 

[Mark S]

Have you checked the two frame above. Yishun also builds carbon wheel, seat posts, bars, add Bafang M600 so USD 3000; with front and rear shocks to add along with breaks, seat, peddles, group set ... if you use SRAM for e bikes, you’d spend about $5700 for an all carbon eMTB. If the frame geometry is good you can make it handle
Cheers
Mark

 

[Mark S]

so what did the bike cost to build and what was the total weight ,

I have not built it yet, but see my post from a few mins ago ... about USD 5700 for an all carbon eMTB

 

[craig landau]

check these guys bikes out wood u ride one

 

[All Mountain Coaching]

If the bike has a throttle, it's a motorbike. End of IMO

 

[Indigo]

I’m going to try a couple at least. Do you know if the mag Brose Specialised has this feature?

Yes, the 2019 Levo has a tuning feature called shuttle mode -- enabling you to adjust between 0% (fully peddle torque controlled) and 100% (overall power controlled, which is a combination of torque and cadence).

I have shuttle mode set to 50% via app BLEvo. In BLEvo, I have Smart Power: 68 Watt(+/-10) -- dynamic legs power.

Stats from my last ride:
Average biker power 68 Watt, (max 182 Watt)
Average motor power 326 Watt, (max 681 Watt)
326 / 68 = 480% support.

The law states 250W nominal (averaged over 30 mins) and maximum assist speed of 25km/h. Peak power can be anything, the most I've seen so far is 724W.

 

[Marke]

Another really great thing about this bike is it should last indefinitely.... like triggers broom. The bafang motors are very popular and you can buy spare parts for the motor internals. The motors also accept a wide range of batteries including home made. If your clocking up serious miles commuting or riding your bike really hard in wet conditions you won't need to buy a whole new motor when it fails out of warranty.

 

[Jamsxr]

It’s this sort of thing that will get eBikes banned. Timmy builds ultimate eBike and knocks over/kills/hurts Mrs Miggins, hits the local news, national news etc...

Fair play to the guy for building it up and putting in the effort, but if you really want to go this route I would hazard a guess it’s cheaper to buy a eMTB and tune/modify.

As mentioned above, it’s got a throttle, it’s a motorbike, end of... Take that thing to a bike park or trail centre and it will be rattling and loose in no time.

 

[R120]

I would say all the existing major motors have enough power for anyone to get up any hill - I live in Surrey Hills and various older members of my family have Bosch motored hybrid bikes - they are all in their 70"s and early 80's and have no problem riding them up any hill round here.

There are also several members on here with disabilities who have no issues with the power of standard bikes.

If you need to ride the bike in turbo the whole time, then the main issue is going to be battery usage. A more powerful motor like a Bafang, is going to go though its battery in full power just as fast as a Bosch or Shimano at full power, so what you really want out of a bike if you are going to be using maximum assistance all the time, is a big battery.

If you need a throttle you can buy a Speed Pedlec, but there are quite a lot of regulations about using them on the road, as they are legally viewed as a moped.

Also it is critical if building a bike with a throttle, that it has a brake system linked into the motor system, so that the throttle cuts out when you use the brakes.

If you are interested in a self build, I would suggest talking to the likes of Brighton Bikes, who are a great shop, and have a wealth of experience building safe and useable bikes with the Bafang and similar.

Brighton E-bikes transform your favourite bike into a UK road legal E-bike & inject more smile per mile.

 

[Marke]

Looks like you can run the bafang M620 in pedal assist mode only - i.e. no throttle. You can also adjust the power levels through the software.

 

[R120]

Yes the bafang systems essentially work like all the major brands when used in a Pedelec application - on mainland Europe, where E-Bikes are a lot more common, you see a lot of Bafang equipped bikes, for example a lot of the big supermarkets sell own brand E-Bikes and they have Bafang systems.

 

[thewildblue]

Think the weight was 26kg from what he replied to me on his facebook thread. Dont think the battery has BMS either...

 

[R120]

E.G this Toplife which I saw in a Leclerc supermarket when on holidays last, year, running a Bafang system