Electric downhill/freeride bike

[Ratking]

Awesome job Ratking, I like the way you integrated the suspension. That bike should handle like a dream, all the weight is is in the right place. excellent!

Thanks, I hope it handles like a fat big hit
Would like to have more than 1.25kw of battery, but done is done. Have to be the next frame

 

[Ratking]

Hello guys!

I got a fair bit done today, but not much to show for it.
I did make my first keyed slot, both in an axle and two sprockets. I have made slots before, but not inside a sprocket/hub.
It was fairly easy with the right tool.

There is just a few more things to do before I can take it for a ride, much will come together the next days.
I am waiting for the freewheels, but I will get them soon enough.

Some pictures:

 

[Ratking]

Hello guys!

I got a big boost when I could sit on the bike for the first time. I just mounted the wheels and frontfork, still many pieces left off, but it was a great feeling to know that almost all the mechanical work is done. I have a few details, and a lot of soldering left, but that is nothing compared to all this.

As is, in the picture, with one of the motors fitted, and only missing pedals and a few misc parts it weights in at 24.6kg. Compared to the 21kg of the original bike, i think I am doing well enough. On top of that there will be 12kg battery, 1.5kg motor, controllers+ misc 3kg.
From that I think I could manage to get under +/-42kg ready to drive. I am so exited

 

[geetarboy]

Looks good Ratking, weighs about the same as my green bike loaded w/ 24s 10ah lipo 86lbs. What's the wheelbase & rake angle?

 

[Ratking]

Looks good Ratking, weighs about the same as my green bike loaded w/ 24s 10ah lipo 86lbs. What's the wheelbase & rake angle?

I've tried to keep the original design from the big hit frame I took the design from, only difference is the frame that is made 30mm longer behind the cranks.
The rake angle is around 67-68 degrees. Should be good for some offroad rampage.

 

[lostrack]

Looks great mate. You must be very pleased so far!

 

[Ratking]

Looks great mate. You must be very pleased so far!

You bet I am. I played a bit with the beta ca-rc in current mode. Limited to 5 amps, and I could not stop the motor from rotating, crazy amount of torque(if my shunt value is right that is).
I already fear the power of two of those beasts

 

[Ratking]

I hate makita/konion batterys.
I've been testing every single cell for capacity, voltage drop over time and resistance. All good, and the 12s6p modules did hold capacity and voltage for several weeks. Today, when I was about to charge them up before testing, two rows of cell where dead. How is that possible? No sign of damage, leak or anything that could help me understand what happen. Just dead cells. I don't trust these anymore and will buy some hardcase batteries instead.
Talk about bad timing, just when I was about to test the bike

 

[Ratking]

Hello guys

Time to update this tread, been doing lots of stuff lately. Tud was kind enough to help me splining two freewheels. I go them in the mail and made an adapter between them and the sprocket.
I also made a system out of all the wires that I did no know what to do with. Since I got a lot of rc stuff, I decided to use ordinary 3 pin plugs for all the signal connections from the ca to the controller etc.
That way I can disconnect everything without any soldering.

My makitapack decided to burn a few cells when I was away from home today, some burnt plastic, but no other damage. I was lucky this time.
Since the makita project went south, I bought 15 4s hardcase packs instead. I don't want to waste anymore time on batteries. I won't get as much capacity on board, but I don't care as long as they don't burn and stay alive.

On a positive side, I go my first test ride today. Started out with a saggy dead pack at 43v and limited the ca to 20A. Did not give me crazy acceleration, so I stared to up the limit in 20A steps. 60A started to get fun but 150A was much more impressive. Due to massive sag I could not get to full 150A because the ca started to limit because of the lvc. Still more then enough to lift he front wheel and give me a big smile. There are some stuff I need to address, but all in all very fun. Its very noisy, first reduction should probably not be chain, but the motors itself makes a lot of noise without the chain also. Seems like the steel frame resonates the vibrations. Have to look into that, but for now I will focus on getting the bike working completely.

 

[sn0wchyld]

great to hear your up and running!

let me be the first to say... videos! Love to see those twin motors spinning!

and is that 150A total, or 150A per motor? sound like a pretty sane and reasonable level of power... :wink:

 

[Ratking]

great to hear your up and running!

let me be the first to say... videos! Love to see those twin motors spinning!

and is that 150A total, or 150A per motor? sound like a pretty sane and reasonable level of power... :wink:

That's a total of 150A battery side. I swapped a few rows of shorted konions, so my pack is up and running at 50v. Had a bit of rain last night, but it's been drying up, so I am out the door to test it out with some more amps

I will take some videos when I feel that things work. As for now I am sorting out bugs.

 

[Ratking]

Hello

I've been having some good and bad experiences with the bike. First, ThrO->UpRamp needs to be very low. Its 500 as default, that is terrifying even at 150A. I set it at 250, that is aggressive enough. My first attempt with freshly charged battery ended very bad at 150A limit. It started with a wheelie without rear brake fitted and just had to try to run the speed of. Needless to say, I did not have a chance so I ended being dragged after the bike. Still got some fresh wounds from that.

I can't imagine the bike at 200A. I will have to tweak everything and slowly work myself up there, because this is a bit scary much power

I understand why people are scared by rc-motors. They have brutal torque and if no careful it will hurt you. I am just glad I did have the beta rc-ca to manage the power to healthy levels.

The konions are sagging like nothing I've seen. I've seen them drop from 49.5v to 43 ish volts. Thats with a 18Ah pack. They should manage at least 180A without problems. Don't know how much sag I should except, any ideas?

 

[mdd0127]

I don't have any first hand knowledge of Konions but my turnigy lipo sags from 49.5v to 47v at a 160A load. It's a 12s 15ah pack but I'm only getting 13ah out of it before it starts going way out of balance. Turnigy lipo is neat when it works but overall, it's a waste of money.

Awesome build BTW!

 

[Ratking]

I don't have any first hand knowledge of Konions but my turnigy lipo sags from 49.5v to 47v at a 160A load. It's a 12s 15ah pack but I'm only getting 13ah out of it before it starts going way out of balance. Turnigy lipo is neat when it works but overall, it's a waste of money.

Awesome build BTW!

Thanks, I think I have room for 24Ah of konions, but I can't imagine that I can pump out anymore than 200A without massive sag. Thats strange, the internal resistance is around what the specs on the konions says, but still saggy.

I read that you had plans for building an awesome bike yourself, how would you build it? If I was to make another frame I would make more room for batteries and for the controller. If you want big power, big batteries are needed. I would say no less than 15Ah. With two motors, two controllers, drive line and batteries it hard to keep the complete bike under 40-45kg.

 

[mdd0127]

I don't have any first hand knowledge of Konions but my turnigy lipo sags from 49.5v to 47v at a 160A load. It's a 12s 15ah pack but I'm only getting 13ah out of it before it starts going way out of balance. Turnigy lipo is neat when it works but overall, it's a waste of money.

Awesome build BTW!

Thanks, I think I have room for 24Ah of konions, but I can't imagine that I can pump out anymore than 200A without massive sag. Thats strange, the internal resistance is around what the specs on the konions says, but still saggy.

I read that you had plans for building an awesome bike yourself, how would you build it? If I was to make another frame I would make more room for batteries and for the controller. If you want big power, big batteries are needed. I would say no less than 15Ah. With two motors, two controllers, drive line and batteries it hard to keep the complete bike under 40-45kg.

How would I build it?

That would be an extremely complicated answer and would call for a thread of it's own....maybe even a book. I'm going to do it eventually. I'm just waiting to be in a better position to get it done.....and waiting for motors, controllers, and batteries to come out that are reliably available and worthy of the effort of designing a frame around. I have all of the parts to build it right now though. I just don't have the time, motivation, and stability to commit to the project 100%. I need some alone time to finish all of the drawings and once those are all done, I'll whittle away at getting all of the parts made. Everything's getting close and if the economy doesn't completely collapse, it might all come together soon. If you search my posts, I've mentioned a bunch of my ideas about it in random threads over the years. The project totally bankrupted me, was a major factor in ruining my last romantic relationship, and has been a huge struggle from day one so I just can't go after it with the gusto I once had. I still think about it daily though and so far, no one's even close to doing something similar. If I had some funding and some help with drawing and building, I could jump right back in but building something that will not only compete with, but blow away everything else that's out there is too much of a job for one broke, broken man.

 

[Byte]

I don't have any first hand knowledge of Konions but my turnigy lipo sags from 49.5v to 47v at a 160A load. It's a 12s 15ah pack but I'm only getting 13ah out of it before it starts going way out of balance. Turnigy lipo is neat when it works but overall, it's a waste of money.

Awesome build BTW!

Thanks, I think I have room for 24Ah of konions, but I can't imagine that I can pump out anymore than 200A without massive sag. Thats strange, the internal resistance is around what the specs on the konions says, but still saggy.

I read that you had plans for building an awesome bike yourself, how would you build it? If I was to make another frame I would make more room for batteries and for the controller. If you want big power, big batteries are needed. I would say no less than 15Ah. With two motors, two controllers, drive line and batteries it hard to keep the complete bike under 40-45kg.

How would I build it?

That would be an extremely complicated answer and would call for a thread of it's own....maybe even a book. I'm going to do it eventually. I'm just waiting to be in a better position to get it done.....and waiting for motors, controllers, and batteries to come out that are reliably available and worthy of the effort of designing a frame around. I have all of the parts to build it right now though. I just don't have the time, motivation, and stability to commit to the project 100%. I need some alone time to finish all of the drawings and once those are all done, I'll whittle away at getting all of the parts made. Everything's getting close and if the economy doesn't completely collapse, it might all come together soon. If you search my posts, I've mentioned a bunch of my ideas about it in random threads over the years. The project totally bankrupted me, was a major factor in ruining my last romantic relationship, and has been a huge struggle from day one so I just can't go after it with the gusto I once had. I still think about it daily though and so far, no one's even close to doing something similar. If I had some funding and some help with drawing and building, I could jump right back in but building something that will not only compete with, but blow away everything else that's out there is too much of a job for one broke, broken man.

Sorry for going off-topic... But how much is that bike going to weight approximately? And at what power levels?

 

[mdd0127]

75lbs or less, 8-10kw with the current drivetrain, 20ah @48v, 8+ inches of travel at both ends, fat tires, on the fly adjustable geometry and seat height, all belt drives, nuvinci in frame, hammerschmidt. PM me if you want give me a bunch of money. :lol:


Back to your regularly scheduled programming. :wink:

 

[Ratking]

75lbs or less, 8-10kw with the current drivetrain, 20ah @48v, 8+ inches of travel at both ends, fat tires, on the fly adjustable geometry and seat height, all belt drives, nuvinci in frame, hammerschmidt. PM me if you want give me a bunch of money. :lol:


Back to your regularly scheduled programming. :wink:

I'm sorry things did not go your way, but maybe some day you will have a high quality product that people will pay premium for. I hope that day will come when batteries and controllers are solid and cheap.
For now I just play around with whats available.



I just want to ask how you would make it that lightweight with todays technology?
I've played around with some numbers, and thats a hard weight to beat.

Lets take a high end Specialized Demo 8, it weighs 17-18kg.
12s 20Ah lipo, Turnigy nanotech 6s 5Ah, 800g per brick. Eight needed, 6,4kg http://www.hobbyking.com/hobbyking/store/__14616__Turnigy_nano_tech_5000mah_6S_45_90C_Lipo_Pack.html
The lightest controller would be a hv 160, thats 210g
I don't know about a suitable motor for 8-10Kw, but lets say a 80-100. Thats 1,5kg, you wont find any lighter motor capable of 8-10Kw(This one is not, so I would guess that you will need a bigger heavier motor. Copper and steel weighs a lot)
Misc hardware as chains, sprockets etc: 4kg.
Total: 29-30kg or 66lbs

But then you don't have any mounts, just a bare frame. I don't know if it is feasible or not. If I had the money I would like to give them to you so I could see what you could create.

 

[mdd0127]

Your build so far is awesome. It's a great idea to experiment with what's available now because when better stuff comes out, you've already learned all of the basic lessons and can implement the new stuff very efficiently. I've showed your thread to a few friends and they have all be really impressed!

Your calculations about the weight are right on. If the frame actually contains the mounts for everything and belts are used to replace the chains, it's totally possible to get something done under 75 lbs. I've weighed all of the individual components and had 12 lbs left over for the frame. So using aluminum with carbon fiber inserts/side panels, I know I can get really close to target weight. Also, my test bike is exactly 75 lbs and it's frame weighs at least 20 lbs. The fork is heavy. The battery box is wood. I used vintage steel snowmobile bars. The reduction has separate mounts and supports. A sub 75 lb freeride bike is definitely possible and something refined would really boost the public image of e-bikes. One McAskill video and high performance e-bikes would go viral.

The money thing is tricky. Most of the people that have money these days got it from following the status quo. A bike like we're developing would really shake things up which is scary for investors. I'm more likely to get paid to shut up about it than I am to find a real investor that's willing to get behind it seriously enough to take it to market at an economy of scale that will actually make it affordable.

 

[recumpence]

You hit an interesting point........

The vast majority of consumers are into the status quo. We run against the status quo. That is an inherantly incompatible scinerio.

Public opinion needs to change. One way to do that is to improve quality and reduce cost simultaneously.

Matt

 

[mdd0127]

You hit an interesting point........

The vast majority of consumers are into the status quo. We run against the status quo. That is an inherantly incompatible scinerio.

Public opinion needs to change. One way to do that is to improve quality and reduce cost simultaneously.

Matt

It's a booger of a catch 22 isn't it.
People won't put money into it until there's a big demand but it takes a lot of money to build something awesome, release at a scale that will make it affordable, and market it sufficiently to build demand. It's going to take someone with a ton of money and some juevos grandes.

 

[Ratking]

Your build so far is awesome. It's a great idea to experiment with what's available now because when better stuff comes out, you've already learned all of the basic lessons and can implement the new stuff very efficiently. I've showed your thread to a few friends and they have all be really impressed!

Your calculations about the weight are right on. If the frame actually contains the mounts for everything and belts are used to replace the chains, it's totally possible to get something done under 75 lbs. I've weighed all of the individual components and had 12 lbs left over for the frame. So using aluminum with carbon fiber inserts/side panels, I know I can get really close to target weight. Also, my test bike is exactly 75 lbs and it's frame weighs at least 20 lbs. The fork is heavy. The battery box is wood. I used vintage steel snowmobile bars. The reduction has separate mounts and supports. A sub 75 lb freeride bike is definitely possible and something refined would really boost the public image of e-bikes. One McAskill video and high performance e-bikes would go viral.

The money thing is tricky. Most of the people that have money these days got it from following the status quo. A bike like we're developing would really shake things up which is scary for investors. I'm more likely to get paid to shut up about it than I am to find a real investor that's willing to get behind it seriously enough to take it to market at an economy of scale that will actually make it affordable.

Thanks man, I appreciate the kind words.
The only reason I chose to use chain in the first stage was to get the bike narrow. After some testing I can tell that I don't like the sound of chain at high speed. I think timing belt is the way to go. A bit tricky since I would need a belt with tooths on both sides due to the two motors.
I've learned a ton by building a bike myself. One can learn a lot by reading, but when you have to actually make every detail and decision is when you see how complicated everything is. But I love it this way, I am the creator of my bikes and I am the limitation for how good the results will be. Money is a problem, but I have time on my side.

About making this kind of bikes commercial, I don't know. I know too well what would happen if this product would be huge and popular. It would be regulated and killed by all the rules and laws. Since I am on of the few I my country(that I know of) with a high power bike I don't have to worry about the police, because they don't have any clue what it is. I would like it to stay that way a couple of more years. I know its selfish, but I would rather have a bike that I can use everywhere than be one of thousand with a 250w pedeleck limited bike. I cant ride a downhill bike at 20-25km/h when it begs for at least 50 km/h

Btw, I got 15 hard case packs on the way, as inside my country, only hours away. That will make a nice 12s 25Ah pack. Too bad I only have space for 12 of them, so a 12s 20Ah pack= 888Wh inboard. If that is not enough I can build a pack for my backpack that can be as big as I want to/can carry out of konions. I should have bought a few packs of the best nanotechs instead of the cheap hardcase packs, but done is done.

 

[drewjet]

I am happy to see you are finally gettting to ride it. It is an AWESOME build! With the abilties you have shown throught this build, I am sure you will get all the bugs worked out.

On my Astro mountain bike build I used a belt drive and found it was not up to the power of one Astro, let alone 2 Turnigys. If you used the wider belt than maybe, If i recall mine was the 10mm. I now have a #25 chain on the primary and while it handles the power OK it could be better. It is not that much noiseier than the belt drive, I think a lot of the noise comes from the high speed of the motor and the necesity of double reduction. If I had my choice I would use #219 chain for the primary. I have had great success with it on the secondary.

I also am using 219 with a single reduction on my race bike with an Etek motor, and it is nearly silent, and handles the 25KW peaks just fine.

 

[Ratking]

Yeah, I got my batteries, and all of them are balanced(almost)

Have to say this, the batteries where bubble wrapped and in separate cardboard boxes with another bubble wrap layer. Not a sign of damage or funky cells. All batteries came in with voltages between 3.83-3.88v but one pack that had one cell at 3.75v. I bought a few spare packs, so no worry there but I hope I can use that too.
Good times for a bike builder

 

[Ratking]

I am happy to see you are finally gettting to ride it. It is an AWESOME build! With the abilties you have shown throught this build, I am sure you will get all the bugs worked out.

On my Astro mountain bike build I used a belt drive and found it was not up to the power of one Astro, let alone 2 Turnigys. If you used the wider belt than maybe, If i recall mine was the 10mm. I now have a #25 chain on the primary and while it handles the power OK it could be better. It is not that much noiseier than the belt drive, I think a lot of the noise comes from the high speed of the motor and the necesity of double reduction. If I had my choice I would use #219 chain for the primary. I have had great success with it on the secondary.

I also am using 219 with a single reduction on my race bike with an Etek motor, and it is nearly silent, and handles the 25KW peaks just fine.

Thank you, far too kind. Everybody can do this with the right tools. I've looked at a T10 profile, 25mm wide belt. Should handle 15kw cont. under the right circumstances. All though I will test the chain a bit more to find where the noise come from.
Good to hear that you have good experience with 25# chain, gives me hope. I have not found a good source of 219 parts, so I just ruled that out. Maybe thats the ticket.