New 24' slopestyle freeride build, getting serious!

[bzhwindtalker]

Allrigth i'm racing there next year : rock and solex




Old school French racing. Thats me on a fiends solex practicing cornering! only one electric was there, with a brushed motor and slas... but last year it was an electric that won. I have a quite good idea of what I need to do to have a winning setup. 150 ICE riders's butt to kick is not something i can ignore

[Stone Meadow]

I understand how the mid-mount hub motor transmits power, but what I haven't figured out is how you attach the freewheel to the side cover of the motor, as in this photo:



Is there an adapter? Do you bolt it yo the brake disc flange? Bolts through the case? Something else? Thanks!

[bzhwindtalker]

this is how I did It : I do not have a freewheel on the motor, just a track bike sprocket+lock nut screwed on the regular right side of the motor. As the lock ring was still unscrewing from torque, I tack welded it to the steel treaded insert. I would ned to grind that of to be able to change the motor sprocket, but it is do-able!


I have nothing left to ride from last failure, so I pulled an older frame from my pile of busted bikes, this will probably do the job while I build my next frame :


It has a nice feature : the batt will fit inside the triangle, resting on the two front motor mounts. how many riding hours before destruction?

[Stone Meadow]

this is how I did It : I do not have a freewheel on the motor, just a track bike sprocket+lock nut screwed on the regular right side of the motor. As the lock ring was still unscrewing from torque, I tack welded it to the steel treaded insert. I would ned to grind that of to be able to change the motor sprocket, but it is do-able!

Ah...thanks! Any chance you can snap a photo to show the naughty bits?

Oh, and your new wheels? I'm guessing it lasts 1 hour of harsh riding...

[bzhwindtalker]

This is exactly how I did it :

You may notice I removed the thick steel flanges, this saved an impressive amount of weight! and it makes the motor quite small. To anybody searching for a big mofo outruner that makes huge torque and is drivable with any cheap ebike controller at only 5,5kg... search no longer :



220 mm external diameter and 32mm stator, this ends up as a 32x200mm motor, this is a lot of motor!



I tryed something on this frame, with dynema kites lines and marine grade PPU 100 glue. It is an experiment but I am quite confident!






Anyway if this thing holds together while i build a real frame (No tubes yet!!! it's been a while) I'll be happy enough to have something rideable.

Adam

[Stone Meadow]

Thanks Adam...now let me make sure I understand correctly!

In the blow-up photo below I see what appears to be a cut-down freewheel that's been threaded onto the boss that holds the cassette for a RWD hub motor, right? You just tacked it in place to prevent it coming loose...correct?

Edit: Not a cut-down freewheel. Just a regular thread-on sprocket/nut...

[bzhwindtalker]

You are rigth, exepted that the tack is on a lock ring and not on the screw-on sproket itself. It is not overly complicated, you just need a welder, I did that with my stick welder... This method seems pretty bombproof to me!

[bzhwindtalker]

The glue cured, it looks nice and strong but this thing produce a lot of torque! Time will tell...

[Stone Meadow]

You are rigth, exepted that the tack is on a lock ring and not on the screw-on sproket itself. It is not overly complicated, you just need a welder, I did that with my stick welder... This method seems pretty bombproof to me!

Thanks for the clarification! I have plenty to welding capability...just not enough ebike experience to know quite what I was looking at. I'm doing my first build for my wife now (a low powered front hub), but am planning out a more ambitious approach for my own bike.

[Thud]

Biz,
I do like the glue idea...but I fear you need a little more prep work to the alloy for proper adheasion. You went right over the decals on the frame?.....if they are any polymer based sticker...its only a matter of time.

Sorry to be a buzz killer...a quick google would have had you strip the frame at the bonding points & etch the metal for a better chance of success...No big deal as an experiment, Just don't be discouraged when it fails.

You will see potentialy a 400% increase in joint strength following established procedures for bonding metals with epoxy.

Hope I am prooved wrong.....keep up the good work.

[bzhwindtalker]

Haha yeah I know...
Those old kitesurf lines are un-stretchable and the knot by itself was already quite strong, with a pattern preventing the mounts to twist around so the glue was only extra.

The shock mount on my 20' bike was holded like that, only with epoxy instead of PU. I had high quality epoxy around but the hardener leaked, and I tryed multiple times to source carboon wire but never found a cheap enough source.

This is just a "ridable mock-up" I'll update tomorow morning! I cant wait to start making my custom frame, I NEED MOAR STEEL!

[bzhwindtalker]

The mount is holding up fine, BUT I can't get a chainline to work well on this frame. So I just put a single chain going from the motor to the derailleur, and it works wery well! but the pedals are doing nothing now... One thing I would like to try on my next build is using the hub as a jachaft, with the pedals powering one side and the motor power being delivered directly to the rear derailleur on the other side! This would be neat, especially with a freewheeling motor like a MAC.

Oh and I put some DH 2,6 inchers knobbies on this rig, makes me much more confident in high speed offroad bashing!!

I have a new POV camera to play with, I have some bakyard wheelies video coming soon!

still waiting my steel order grrrr

[bzhwindtalker]

Video is curently uploading, raw from the camera.
should be done in 1h or so ~ Hope you like it!

edit : wow the sound got degraded so much by yt!

[bzhwindtalker]

I will probably go with Rc lipo from the German hobbyking warehouse for my next pack.
The hardcase packs come in quite cheap for a respectable 16s 10ah pack, plus shipping is fast and cheap. However i'm pretty sure that my current sensorless controller has 63v caps, no workie! I have a hua tong 15fet on hand too, but I don't know the lvc... I would like to go with the hardcase because they offer some protection to the cells. but then my options are only 12, 16 or 20S...The best compromise would be 15s, right on the edge of a standard controller, but 14 would work too. I dont really need or want to go much over 70v fully charged, and I only need 2500-3000w continuous... Opinions?

[Whiplash]

I am amazed that glue is holding! LOL! Nice job on the quickie fix!

[binlagin]

Rear brake left hand side?

[bzhwindtalker]

Yep it took some crashes to get used to it, but now it's really nice!

[binlagin]

Yeah, well front brake on the right hand side is standard for motorcycling.

I've been debating doing the switch so I can do wheelies too! Back brake on the right side with throttle makes it VERY challenging to use the brake to prevent a tip over

[ElliottE]

It has a nice feature : the batt will fit inside the triangle, resting on the two front motor mounts. how many riding hours before destruction?

You just gotta admire that kind of spirit...
I'm currently debating the pros and cons of a couple of different mid-drive approaches. One is to use a hub motor, as you are doing. The other would be to use a scooter motor such as a BMC, which would be somewhat more compact than the hub motor. Anyone have any thoughts on the pros and cons of either approach?

[bzhwindtalker]

A hub motor has the interest to be extremely easy to gear to the rear wheel, and would work really really well on a high voltage setup. Plus it is super easy to build a multispeed setup if you stay below 5kW. On the other hand a BMC or Mac 2000w motors could be a really nice option, with a nicer powerband if you use single speed, may be easyer to mount to the bike, but need 1/8 gearing, wich is still easy to achive with karting chain and can handle way more power than typical bike chain.




Latest frame design : I am going lightweight, with a smaller lipo battery. The chain arrangement has changed too, to have a good suspension comportment under motor load. This should work quite nicely and be simple to build. Still no tubes, this is pissing me off




Adam

[Tench]

Adam, i like your layout i can see some thought has gone into that regarding the chain pull and its influence on the rear suspension. I do think you need to raise the swing arm pivot a little more though, just enough to combat the sag from your weight, unless of course it has been drawn with the suspension loaded? in which case i think it is spot on! This will make a nice very useable bike that handles the transition from off the power to on it very well with minimal reaction from the chassis. I like how you have given priority to the motor chain and re-thought the pedal chain to accomodate this layout, Get it made!!

How about putting a fixed roller on top of the chain just above the swing arm pivot (the higher the chain is above the pivot the more it will try to pull the swingarm upwards when under power) this will keep the chain close to the pivot even under large suspension compression reducing the powers tendency to create squat and will help with keeping the chain at a more constant tension through the suspension travel giving the derailier an easier life with less chance of the chain jumping if the derailier cant react fast enough to keep the slack in check? Derailiers dont have very strong springs.

Your well on your way to a good design here Adam.

[sn0wchyld]

Adam, i like your layout i can see some thought has gone into that regarding the chain pull and its influence on the rear suspension. I do think you need to raise the swing arm pivot a little more though, just enough to combat the sag from your weight, unless of course it has been drawn with the suspension loaded? in which case i think it is spot on! This will make a nice very useable bike that handles the transition from off the power to on it very well with minimal reaction from the chassis. I like how you have given priority to the motor chain and re-thought the pedal chain to accomodate this layout, Get it made!!

How about putting a fixed roller on top of the chain just above the swing arm pivot (the higher the chain is above the pivot the more it will try to pull the swingarm upwards when under power) this will keep the chain close to the pivot even under large suspension compression reducing the powers tendency to create squat and will help with keeping the chain at a more constant tension through the suspension travel giving the derailier an easier life with less chance of the chain jumping if the derailier cant react fast enough to keep the slack in check? Derailiers dont have very strong springs.

Your well on your way to a good design here Adam.

ahhhh my head... that was a long sentence! hheheh. good point though. Does anyone have experience of how guides like that handle the tention under power? I'm mainly asking in regards to efficiency... in my head it seems like putting a great deal of tension across it would create quite a bit of friction and other losses... if not though it'll really help my next build.

as usual bhz... love ya work. gearing your pedals up to the motor speed is a great idea.

[bzhwindtalker]

Thanks for the advice, I totaly forgot about suspention sag let's say I had it planned in that draft is 15-25% of sag reasonable?

I went out riding today, but I kept braking links on my chain... I think I should go with stronger chain with a single speed to the rear wheel and more volts but the same low gear to keep the brilliant torque, and use bike chain for the bike stuff! in the current configuration the bike pulls really well and is very controlable. 30-35mph top speed is fine for me, and single pedal speed is okay too. Ill see when I get my stuff to build the new frame I guess, but breaking chains all the time starts to be annoying

Adam

[ElliottE]

Just out of curiosity, have you considered using a belt final drive? Such as the Gates Carbon Drive?

http://www.carbondrivesystems.com/

[bzhwindtalker]