|Campus Rider MK I.5| Weld-free Electric Long Board

[torqueboards]

Lpbug - There are ABEC 11 clones with a thin core line and ones with a thick core line. You currently have the thick core. That core is different than the real abec flywheels. If you get the thinner core lines then they are pretty exact to the original ABEC 11 flywheels. That's the ones I use. I received the thick ones as well but returned them for the thinner ones which are the same as the ABEC 11 flywheels originals.

 

[lpbug]

Do the thin cores have smaller hubs or bigger hubs?

 

[torqueboards]

Do the thin cores have smaller hubs or bigger hubs?

They are the same cores. The only difference is the thickness of the core lines. The one you originally have I call the "thick core lines" and the original abec and the flywheel clones have what I call the "thin core lines".

The flywheel clones and original abec 11 flywheels are pretty much the same hub - there isn't too much different. I believe the clone cores are all the same size up to 97mm. They only difference is some are thin core lines and thick core lines.

I prefer the thin core as they are compatible w/ the original abec 11 flywheels.

 

[lpbug]

I see what you mean by core lines. I measuredboth of them just now and it seems that the geometry is identical for the hub save that one is more elongated in the rotational direction. Shouldn't be hard to modify the existing hub stops for it. Thanks for the pointers torque.

 

[torqueboards]

I see what you mean by core lines. I measuredboth of them just now and it seems that the geometry is identical for the hub save that one is more elongated in the rotational direction. Shouldn't be hard to modify the existing hub stops for it. Thanks for the pointers torque.

Here's an image of both. The left is an 83mm with thick core lines which my original design didn't fit. The one on the right is a 97mm with a thin core as I didn't have any 83mm w/ thin core. Don't know why they would have 2 different core lines. Although, the thicker core lines I would imagine would be stronger but they don't fit the original abec's which makes it not compatible which isn't worth it. I wish they sold 76mm abec clones they only have 83/90/97mm wheels.

Do you think it's needed to switch over to 15mm? I've been thinking about it but definitely need more clearance for 15mm pulleys. On regular terrain it's not needed at all only when traction isn't there.

 

[lpbug]

Yeah I see where you're coming from. Why use 76mm wheels though? Also- I would definitely want to try using 15mm belts. at some point especially for single wheel drive. I haven't had much problems with the 9mm (rare slipping when belt is not tensioned when pulling full throttle) but 15mm sounds very reliable for full throttle. What about you? Are you considering switching to 15mm?

 

[torqueboards]

Yeah I see where you're coming from. Why use 76mm wheels though? Also- I would definitely want to try using 15mm belts. at some point especially for single wheel drive. I haven't had much problems with the 9mm (rare slipping when belt is not tensioned when pulling full throttle) but 15mm sounds very reliable for full throttle. What about you? Are you considering switching to 15mm?

I want 76mm wheels for lighter board, easier to carry around and lower to the ground.

I haven't had any problems with 9mm either except for trying to ride on carpet and/or surfaces that provide no traction for the wheels. I'm about 180lbs and can ride on my board with 9mm's fine on carpet occasionally it gets stuck. Put a 230lb person and the wheels sink into the carpet and it won't ride as easily. I'm thinking that the issue could be due to the carpet sinking and there isn't much we can do and a 15mm belt wouldn't help. What do you think - would a 15mm belt help?

I also want to switch over as most if not all manufactured eboards come standard with 15mm belts. I'm sure - this is due to reliability and to deal w/ the added weight for riders they don't expect to ride. I do not believe that they have no drag riding as I would think it's just not possible. There will always be drag as there is a belt connected to it. Of course - it's not too often you would kick push.

My 9mm works well and I have over 800+ miles on it up and down hills. I weigh about 180 lbs + 20 lb backpack so about 200 lbs. I brake downhill a lot as well and belts hold up fine. I find my belts last longer when the belt is tight and not loose. Downhill and braking occasionally it will be a bit slower response than usual depending on terrain. I think the 15mm would clear any and all issues as well.

Simply moving to 15mm width and HTD 5mm should be enough. I'm thinking about switching to GT3 3mm pitch 15mm width and wondering if the smaller pitch would be better than a GT3 5mm pitch 15mm.

GT2 3mm pitch 15mm width 28 teeth and a 67T GT2 3mm pitch 15mm width for 1:2.39 gearing ratio on a dual 5055-280kv sk3 on 6S.

But yeah, I mainly want to switch over to see if there's anything I'm actually missing out on with a 9mm and 15mm.

 

[kkEdlund]

Also- I would definitely want to try using 15mm belts. at some point especially for single wheel drive. I haven't had much problems with the 9mm (rare slipping when belt is not tensioned when pulling full throttle) but 15mm sounds very reliable for full throttle.

My 15mm occasionally slips under heavy braking but that is because my driven pulley is not concentric with the wheel (holes were drilled with an electric screwdriver, lol) so it spins off-center. Consequently, it is impossible to keep the belt under ideal tension and slippage sometimes results. Even as messed up as my pulley is, the belt has never slipped under acceleration.

I want 76mm wheels for lighter board, easier to carry around and lower to the ground.

...I do not believe that they have no drag riding as I would think it's just not possible.

...My 9mm works well and I have over 800+ miles on it up and down hills

I'd also like to try smaller wheels, but I haven't found any that I like yet. Kinda tired of flywheels, honestly.

As for no drag, you could use a one-way bearing on the drive pulley if you are willing to give up braking. Then the wheel would not drive the motor when you are coasting and it would be reasonably close to "no drag". I lake my brakes too much to do that, though.

Also, with the good luck you guys have had with 9mm, I think I will be using those on my next build. Torque, you were right: I am still several mm short on clearance for a dual rear Caliber build, and if I can save 12mm on pulleys I think that will give me what I need.

 

[torqueboards]

Yeah, the 9mm are pretty rock solid especially if the belt tension is very tight. I can't do without my brakes either it's too much fun braking. I want to add the 15mm but maybe later on. Should be able to add in precise bolt holes in regular wheels with a CNC similar to boosted's wheels.

 

[kkEdlund]

LPBUg, out of curiosity, why did you use 1/4" plate to make your electronics box? While it can probably survive a nuclear strike, it seems a little on the heavy side for our application.

I cut this out of 0.063" aluminum and riveted it together at the corners, and I actually stood on top of it to adhere the mounting tape to the board. The box didn't seem to mind the fact that there was ~160 pounds on top of it so I think it is strong enough, but it is still heavier than I would like.

EDIT: spelling

 

[lpbug]

Heh- funny you should ask. I work at a lab where there is a huge surplus of free 1/4'' aluminum. The thing is overkill but I don't really mind the little bit of extra weight. I will likely try the bent sheet aluminum method at some point. For your enclosure, is your lid made of metal as well? I have learning baout Faraday cages and it seems like having na all-aluminum enclosure would be detrimental to our rf signals.

 

[kkEdlund]

Well, there ya go! It's tough to beat free :wink:

My box is aluminum and the lid is steel (attached via magnets, lol). I was worried about rf interference too, but it seems to work without issue. I guess the Tx/Rx systems we use are designed to operate over comparatively large distances (100m+), so even with the interference it still has enough power operate over a few feet.

I admit, my understanding of physics is limited to what I learned in high school, but doesn't a time-varying current in the presence of a magnetic field experience some effect from that field? So would it be possible for powerful magnets in close proximity to the ESC/phase wires to interfere with the signals being sent/received by the ESC? Or am I not remembering this stuff right?

 

[lpbug]

Yeah- that would be my guess as to why it still works. I'm not too sure about how a Wii nunchuck would handle though... Not too sure about time varying currents vs. magnetic field but it would not surprised me. I didn't take E&M in high school so everything that I'm learning is all very much new. Your enclosure looks pretty good, how do the rivets work? I would love to see a closer picture.

 

[666yeti666]

I see what you mean by core lines. I measuredboth of them just now and it seems that the geometry is identical for the hub save that one is more elongated in the rotational direction. Shouldn't be hard to modify the existing hub stops for it. Thanks for the pointers torque.

Here's an image of both. The left is an 83mm with thick core lines which my original design didn't fit. The one on the right is a 97mm with a thin core as I didn't have any 83mm w/ thin core. Don't know why they would have 2 different core lines. Although, the thicker core lines I would imagine would be stronger but they don't fit the original abec's which makes it not compatible which isn't worth it. I wish they sold 76mm abec clones they only have 83/90/97mm wheels.

Do you think it's needed to switch over to 15mm? I've been thinking about it but definitely need more clearance for 15mm pulleys. On regular terrain it's not needed at all only when traction isn't there.

Sorry for my interruption, but where did you buy those clone abec11's with thin core ???
thanks
Sebastien'

 

[torqueboards]

I sell them for 4 a set for $35 but you can also get them on ebay.

 

[kkEdlund]

Yeah- that would be my guess as to why it still works. I'm not too sure about how a Wii nunchuck would handle though... Not too sure about time varying currents vs. magnetic field but it would not surprised me. I didn't take E&M in high school so everything that I'm learning is all very much new. Your enclosure looks pretty good, how do the rivets work? I would love to see a closer picture.

The rivets are great. However, when I do another box the aluminum will be thinner. I got the thinnest stuff I could find as scrap, but it is still too much. This enclosure is 0.063" thick, and is WAY stronger than it needs to be. Etching the bend lines with the waterjet was very helpful during assembly, even using a sheet metal brake.

I can get some pictures tomorrow (currently 2AM, lol). Are there any particular areas you are interested in?

And I'll let you know about the Wii nunchuck once I get mine set up. The hardware came in the mail today, now I just need to get the programming straightened out. Hopefully Voodoojar can help me out (he has a pretty good write-up on the subject), as I am a total beginner with that stuff.

 

[lpbug]

I see what you mean by core lines. I measuredboth of them just now and it seems that the geometry is identical for the hub save that one is more elongated in the rotational direction. Shouldn't be hard to modify the existing hub stops for it. Thanks for the pointers torque.

Here's an image of both. The left is an 83mm with thick core lines which my original design didn't fit. The one on the right is a 97mm with a thin core as I didn't have any 83mm w/ thin core. Don't know why they would have 2 different core lines. Although, the thicker core lines I would imagine would be stronger but they don't fit the original abec's which makes it not compatible which isn't worth it. I wish they sold 76mm abec clones they only have 83/90/97mm wheels.

Do you think it's needed to switch over to 15mm? I've been thinking about it but definitely need more clearance for 15mm pulleys. On regular terrain it's not needed at all only when traction isn't there.

Sorry for my interruption, but where did you buy those clone abec11's with thin core ???
thanks
Sebastien'

Ebay. The ones I got come with thick cores so you have to either specify to the seller or buy it from torque (I'm assuming he sells thin cores).

 

[lpbug]

Yeah- that would be my guess as to why it still works. I'm not too sure about how a Wii nunchuck would handle though... Not too sure about time varying currents vs. magnetic field but it would not surprised me. I didn't take E&M in high school so everything that I'm learning is all very much new. Your enclosure looks pretty good, how do the rivets work? I would love to see a closer picture.

The rivets are great. However, when I do another box the aluminum will be thinner. I got the thinnest stuff I could find as scrap, but it is still too much. This enclosure is 0.063" thick, and is WAY stronger than it needs to be. Etching the bend lines with the waterjet was very helpful during assembly, even using a sheet metal brake.

I can get some pictures tomorrow (currently 2AM, lol). Are there any particular areas you are interested in?

And I'll let you know about the Wii nunchuck once I get mine set up. The hardware came in the mail today, now I just need to get the programming straightened out. Hopefully Voodoojar can help me out (he has a pretty good write-up on the subject), as I am a total beginner with that stuff.

The rivets would be nice- I have never used rivets before and don't really know how they are used. Did you use the etch function in OMAX or did you end up putting small holes along the line for the bend lines?

 

[kkEdlund]

The rivets would be nice- I have never used rivets before and don't really know how they are used. Did you use the etch function in OMAX or did you end up putting small holes along the line for the bend lines?

I used the "Etch" cut quality with the waterjet, and it did a fair job. The depth is not perfectly uniform, but it is good enough for a bending guide.

I just used "pop" rivets on the enclosure, and they are pretty straightforward. Here is a simple (almost patronizingly so, lol) animation that seems to get the point across:
http://www.youtube.com/watch?v=9aoXmzdSf_I

 

[lpbug]

1:55 AM, I'm really supposed to be studying for my physics final but nah. I want to share a particular incident two days ago. Well, it's actually more like an accident. Keep this statement in mind from a few posts above:

LPBUg, out of curiosity, why did you use 1/4" plate to make your electronics box? While it can probably survive a nuclear strike, it seems a little on the heavy side for our application.

Yep, and it's also tough enough to give me a concussion. I was rushing back to my dorm because I was running late for doing my physics problem set. And in my haste, I wasn't really watching the road. I don't remember the last 10 seconds before hitting the ground but I was going roughly ~15 mph down the sidewalk. Wanted to merge on the street via an incline, but I guess I turned too soon and went over the corner (where they usually plant grass). There was a height difference, which I probably would have survived okay if not for my nuke-proof enclosure or so I think as I actually have no memory of the cause. I think the enclosure got caught on the step and flew back towards my motor mount, bending it like so and in doing such dropped the baord's speed to 0 while my speed was still around 15 mph:

and

It's not easy to bend that thing-trust me, I've tried to bend it back. The collision forces must have been pretty big. Before I knew it, I saw the ground flying towards my face and me towards the ground. I believe my arm made contact first (thankfully) then my lips and then the part of my skull right above my eyebrow. I went to medical and got checked out- thankfully no broken bones or nerve damage. Just a mild concussion. The doctor who checked me out was thoroughly confused at why I wasn't wearing a helmet and was wondering why "so many of you MIT kids don't protect your brains". Quite frankly, I don't know- convenience maybe? I am either going to go much slower now or get a helmet. I mean, kinetic energy increases with velocity squared and I really don't know what would have happened had I been going 5 mph faster.

Moral of the story: Wear a helmet, pay attention, or just don't go fast.

In terms of damage to the board, things look worse than they are. Surprisingly the caliber truck mounts I machined stood up to the beating and has not deformed. Even more of a surprise- the SK3 motor is still turning without any chatter. My enclosure got ripped off but that's fixable. The bearings in my drive wheel are trash now. Good thing spring break is coming, I will be able to do a build session soon.

In other news: MK I.5 files are now posted. Feel free to comment if you have any questions.

Stay safe everyone.

 

[kkEdlund]

Damn, that could have ended badly. Good to hear you are alright, all things considered. I should probably invest in a helmet myself even though I generally ride <10-12 mph. Most times, you are better safe than sorry...

With your 1.5 build, what thickness stock did you cut the truck mount out of? The fit on mine is not quite perfect, and it has a tiny bit of lateral play. I'm not sure if I should attribute this to the bracket being too thick and the truck hanger tapering down inside it, or a bad CAD model on my part.


EDIT: I just remembered reading the following in the "Worlds fastest skateboard" thread awhile back. I've never crashed badly, but I've got my fair share of blood loss from eboards. So yeah, true story:

cue Chalo in 3,2,1

Riding powered boards is a self-correcting mistake.

If they catch on, I predict the next step will be personal vehicles powered directly by the rider's blood loss.

 

[torqueboards]

Glad your safe and wasn't too bad. I guess, I should wear my helmet more often. I actually don't wear my helmet at all.

 

[lpbug]

Damn, that could have ended badly. Good to hear you are alright, all things considered. I should probably invest in a helmet myself even though I generally ride <10-12 mph. Most times, you are better safe than sorry...

With your 1.5 build, what thickness stock did you cut the truck mount out of? The fit on mine is not quite perfect, and it has a tiny bit of lateral play. I'm not sure if I should attribute this to the bracket being too thick and the truck hanger tapering down inside it, or a bad CAD model on my part.


EDIT: I just remembered reading the following in the "Worlds fastest skateboard" thread awhile back. I've never crashed badly, but I've got my fair share of blood loss from eboards. So yeah, true story:

cue Chalo in 3,2,1

Riding powered boards is a self-correcting mistake.

If they catch on, I predict the next step will be personal vehicles powered directly by the rider's blood loss.

I cut my truck mount out of 3/8'' stock. That thing literally just held on rock solid, did not budge one bit even though the motor mount was deformed. Which way is your clamping force applied?

 

[kkEdlund]

Which way is your clamping force applied?

I just drilled a hole in the easiest place to get to. But now you mention it, it is probably the stupid way The bolt hole is perpendicular to the length of the mount, such that it is clamping against the rounded surface of the bracket (see image below). I imagine it might work better with the bolt going in the same direction as the Alien mount, so the clamp grips the 2 flat surfaces of the hanger instead of the rounded one. Also, that screenshot is slightly outdated. The actual bolt/hole is much larger than pictured. I think it is an m6 in real life.

What's your opinion?

Also, your build is featured here, about 1/4 of the way down the page:
http://www.electricbike.com/cadcam-the-diy-builders-best-friend/

I actually started laughing when I read the caption under the image. That line made the whole post worth reading :wink:

 

[lpbug]

Lol, I didn't order the waterjet pulley- I was able to play with the machine itself - close enough though since waterjetting is so easy. Regarding the truck mount, my first build has truck mounts mounted the same way as yours. However, I soon discovered that there is slight play even under ridiculous clamping force. I changed my clamping direction to how it is now in the MK I.5 mount and everything has been rock solid. I am surprised that you're using M6, in my MK I I used M3 and even with the weak clamping method, it worked. In the MK I.5, I am using an M4 bolt and things have been working pretty great save for a few times that I had to re-tighten the lock nut. Perhaps this will be less of an issue with an M6 bolt.