New 24' slopestyle freeride build, getting serious!

[bzhwindtalker]

Coming from my semi-serious 20 incher build, I wanted a bike that was more usable as a bike, more agile and nervous, but not neccesarly more powerfull.
I was seeing the limits of 20's and 250wh was not enougth when I got used to the 4kw peaks.
The 80-85 I had failed mecanically (phases shorting to the can... vibrations are a bitch) and killed one of my ss190-200 in the process. That's when I decided to take the whole bike apart and do something better
Solving the low end torque issue was one of the objectives, so i decided to go with a pocket bike clutch, and i found a very nice unit for only 25euros, that has a 1/5 #25 chain geardown!
I picked 16 headway cells back in december, I know those cells are far from perfect and way outdated compared to lipo, but as a RC guy I know how those can fail (don't ask me how )
With this bike i will use a 63-74 motor and a trustable ss190-200 on 8s2p, with the option to reconfigure for 16s1p and a sensorless ebike controller if I find one capable of reving this 180kv motor on 48+ volts.
Enuf talkin' :





I hope to get it runing soon, i still need to order a sproket adapter for the rear wheel and wire the pack and electronics.

Big plus to this build : removable from the bike in less than 5 minutes as motor and batts are one single unit!

[lostrack]

Coming from my semi-serious 20 incher build, I wanted a bike that was more usable as a bike, more agile and nervous, but not neccesarly more powerfull.
I was seeing the limits of 20's and 250wh was not enougth when I got used to the 4kw peaks.
The 80-85 I had failed mecanically (phases shorting to the can... vibrations are a bitch) and killed one of my ss190-200 in the process. That's when I decided to take the whole bike apart and do something better
Solving the low end torque issue was one of the objectives, so i decided to go with a pocket bike clutch, and i found a very nice unit for only 25euros, that has a 1/5 #25 chain geardown!
I picked 16 headway cells back in december, I know those cells are far from perfect and way outdated compared to lipo, but as a RC guy I know how those can fail (don't ask me how )
With this bike i will use a 63-74 motor and a trustable ss190-200 on 8s2p, with the option to reconfigure for 16s1p and a sensorless ebike controller if I find one capable of reving this 180kv motor on 48+ volts.
Enuf talkin' :





I hope to get it runing soon, i still need to order a sproket adapter for the rear wheel and wire the pack and electronics.

Big plus to this build : removable from the bike in less than 5 minutes as motor and batts are one single unit!

Looks like it could be a fun bike mate. What are you planning to do with the chain growth under suspension travel? That was my biggest challenge on my build

[farmkid4]

very nice! what battery setup are you going to run as far as BMS etc?

Sharp bike what model is it?

[bzhwindtalker]

Got some work done, I decided to try the sensorless 48v option as I had a 12 fet under hand and I needed my spare SS190-200 for my coroplast RC wing
did some wiring, secured the clutch to the motor axle, tested the thing a little...










I still need to make a sprocket adapter for the back wheel, or mount a jackshaft on the other side to drive the normal chainline, i'm quite undecided for now...
Anyway I made an adapter to gain some clearance to fit a sproket adapter on the disk side, succes.

I will probably run the pack with no bms, and do an individual cell charger system, 'ive been wanting to try that for a long time!


btw the bike is a Vario mezkal, got it for cheap new on ebay, but one day or another i'll get one of these :
http://www.ebay.com/itm/MOUNTAIN-CYCLE- ... 1e6c361816

[GITech]

Nice! Your original build was one of the insperations for my build.

Can't wait for your ride reports and vids!

[damcard]

Nice. I really like how you can remove the entire unit. -Damcard

[bzhwindtalker]

I changed my plans a little I moved the whole unit on the right side, reversed the clutch and ordered freewheeling cranks from SBP, along with some T8F chain and sprocket. This setup will allow me to use gears, which I wanted to try for a long time!
I hope the fw cranks get there fast, I want to ride this bad boy It weights in at just 25,4kg on the scale, probably under 26 when it will be done, with 500wh on board
I calculated the first gear to spin the rear wheel at 200rpm (27kph) loaded, it may be a bit high, especially considering that full rpm gives about 340rpm at the cranks^^
A 10-15 kph first gear would be better for trials and acceleration

[adrian_sm]

Solving the low end torque issue was one of the objectives, so i decided to go with a pocket bike clutch, and i found a very nice unit for only 25euros, that has a 1/5 #25 chain geardown!

Got more details on this little unit? Link? Weight?

Cheers, Adrian

[bzhwindtalker]

here you go! http://endless-sphere.com/forums/viewtopic.php?f=28&t=37141
The unit weights almost nothing, I would say less than 800g... The output chain is actually T8f pitch chain, which is super cheap compared to #219 or #35, but I only found sprockets up to 63t

[adrian_sm]

800g. Cool.

A quick ebay search turned up this. Looks pretty similar.
http://www.ebay.com.au/itm/Clutch-Gear- ... 0614227767

Plans for an RC upgrade to my full suspension bike are starting to fall in to place. Thanks for the help.

- Adrian

[bzhwindtalker]

Yep, Cheap right? I removed the springs on the centrifugal clutch to have it engage at lower rpm, but I think that some slipping will remain under heavy torque loadings, but this will hopefully save the controller from blowing! How much current can a stock 23$ 12fet handle? I need to learn how to mod controllers...

[adrian_sm]

Are you just using the clutch for the RC ESC setup to save it from low speed, high load stress?
So with the ebike controller you should be able to lock/remove the clutch. Right?

WTF T8F chain. Hmmm. I might have to work out how to put a different pitch output cog on for my setup.

Oh. And found a link to the double chain reduction mentioned in your link above for those interested.
http://www.ebay.com.au/itm/Clutch-Drum- ... 4311wt_956

I was actually planning on mounting everything on the rear swing arm for my setup, to hopefully avoid chain growth.

[bzhwindtalker]

Very nice find on the double #25 unit!! A bit more expensive but it should be able to pass some serious torque!

I did not fit hall sensors on my motors, I am using a sensorless 12fet that seems happy to spin the motor up to max rpm (at least no load...)
The clutch will also help to get a smoother throttle response, hopefully.
I don't really understand why those pocket bike parts are not used more??

[sn0wchyld]

Very nice find on the double #25 unit!! A bit more expensive but it should be able to pass some serious torque!

I did not fit hall sensors on my motors, I am using a sensorless 12fet that seems happy to spin the motor up to max rpm (at least no load...)
The clutch will also help to get a smoother throttle response, hopefully.
I don't really understand why those pocket bike parts are not used more??

I think they've got a rep for breaking under load allot... those 49cc engines dont produce torque quite like a electric motor does. still... itll be interesting to see how a double chain unit holds up. anyone got any idea what sort of reduction you get from a box like that?

ps
love the new build mate. what'd you do with the broken 8085?

[adrian_sm]

Yeah. Pocket bike part prices are pretty good. But time will tell on the quality, especially for our different application.

Would you mind giving me some basic measurements of the reduction unit.
- overall length
- diameters at each end
- thickness

I want to flesh out a few mounting ideas.

Cheers.

[gwhy!]

Yep, Cheap right? I removed the springs on the centrifugal clutch to have it engage at lower rpm, but I think that some slipping will remain under heavy torque loadings, but this will hopefully save the controller from blowing! How much current can a stock 23$ 12fet handle? I need to learn how to mod controllers...

I have run a stock 12fet at 70A with a 6374 motor with halls, it was ok but you have to watch the temps.

[Whiplash]

Are you sure the box is 5:1? I thought those were 3:1 when I was going to use them... the gear driven ones are 5:1 but the chains were labeled as3:1 most times I saw them??

[bzhwindtalker]

I plan on running the 12fet at 40-50a so I should be fine! What kind of "stock" 12 fet are you using?

You are right whiplash, they are actually 1/3, I tested mine right now... this kinda sucks because my gearing is way off then :/

Edit, I calculated 45kph in slowest gear unloaded :/

[gwhy!]

I plan on running the 12fet at 40-50a so I should be fine! What kind of "stock" 12 fet are you using?

You are right whiplash, they are actually 1/3, I tested mine right now... this kinda sucks because my gearing is way off then :/

Edit, I calculated 45kph in slowest gear unloaded :/

It was one from e-crazyman ( sensored ) all i done soon as i received it was to add a pot across the shunt ( as Bigmoose have mentioned in another thread somewhere ) so I could adjust the current.

[Whiplash]

I plan on running the 12fet at 40-50a so I should be fine! What kind of "stock" 12 fet are you using?

You are right whiplash, they are actually 1/3, I tested mine right now... this kinda sucks because my gearing is way off then :/

Edit, I calculated 45kph in slowest gear unloaded :/

It was one from e-crazyman ( sensored ) all i done soon as i received it was to add a pot across the shunt ( as Bigmoose have mentioned in another thread somewhere ) so I could adjust the current.

Hey cool idea there!

[bzhwindtalker]

Gwhy, I know you have been up with 12 fets and 6374 for a while, how do you gear your builds (speed)?

I think 45kph will be too higth for a first gear, especially considering that this build will be used 80% of the time on technical offroad stuff, averaging under 20kph. my previous build was geared for 35-40kph loaded, and was pulling hard with a 80-85 at 20v, 2500-3000w peaks and no torque from 0 to 3kph.

The new 63-74 spins more than twice as fast as the 80-85, so it should be able of more power to weigth than the 80-85 bogged at 20v, but still, I realy wish I had a 15kph first gear with tire shredding torque

[Whiplash]

Just use a two stage chain box? I bet you could modify the double row box to be two stage and get 9:1!

[Whiplash]

Excuse the cell phone paint...

[sn0wchyld]

Just use a two stage chain box? I bet you could modify the double row box to be two stage and get 9:1!

I was actually thinking of using 2 boxes put back to back, that way you keep the double chain strength but get a 9:1 in one unit. efficiency might be a bit sucky though.

[gwhy!]

Gwhy, I know you have been up with 12 fets and 6374 for a while, how do you gear your builds (speed)?

I think 45kph will be too higth for a first gear, especially considering that this build will be used 80% of the time on technical offroad stuff, averaging under 20kph. my previous build was geared for 35-40kph loaded, and was pulling hard with a 80-85 at 20v, 2500-3000w peaks and no torque from 0 to 3kph.

The new 63-74 spins more than twice as fast as the 80-85, so it should be able of more power to weigth than the 80-85 bogged at 20v, but still, I realy wish I had a 15kph first gear with tire shredding torque

all my off road stuff has been geared for around 35-40kph when using the 63-74 ( running on 48v with a current limit of around 70-80A), the bikes will take me up and over anything I point them at, the biggest problem that I have had is with throttle control at these sort of power levels is with traction. On the full size motorcycle that I have been playing around with ( that has been put on hold for a little while until I have some more parts ) I geared it for around 30-35kph still using the same small outrunner ( because its twice the weight of my pushbike based bikes but it did end up under powered) I found that the problem with gearing even slower really starts to effect throttle response due to the amount of reduction, this may not be a problem for most but I have always ridden very technical sections where even the slightest of delay in the throttle can be the difference of getting up a 3 foot rockstep after a full lock U-turn or ending up on your a$$. I have never run one of these motors sensorless and I think by running sensors this is where the <1 rpm power/torque comes from, I really cant imagine a sensorless setup working for for the stuff I ride.