The E-cumbent - A project by Matt Shumaker

What I really need to do is develop a single stage reduction unit that incorporates the BMX rear hub with freewheel in a design that is easily manufactured. One thing that is surely required is the current limiter I mentioned earlier. I have actually shredded a 15mm wide 5mm pitch belt with this thing.

Even with all this abuse, the motor, controller, and pack all run nice and cool. :wink:

Oh, the primary belt skip I have been fighting seems to be related to the motor RPM creating a harmonic resonance that makes the belt vibrate and slip on the motor pulley. It is a neusance, for sure. But, it is liveable for now. It only happens right at a specific RPM. At that RPM, I get a bit of motor buzz, then teh belt skips (if under alot of load), then I move the RPM a touch past that point, and it won't skip no matter how hard I push it.

Weird.

Anyway, that is the last technical bug to work out.

The clutch is a God-send.

Matt
 
"What I really need to do is develop a single stage reduction unit that incorporates the BMX rear hub with freewheel in a design that is easily manufactured. One thing that is surely required is the current limiter I mentioned earlier. I have actually shredded a 15mm wide 5mm pitch belt with this thing".


what you REALLY need to do Matt is maufacture the reduction unit to fit into most bike frames :D
i'll take one!!!
are you available for private work ;)


cheers

D
 
Matt, can you comment at all on what may come from your talks with the recumbent bike manufacturer? I'd love to see this gear packaged as a kit -- I'd buy it, recumbent and all, no joke.
 
So far I have been contacted by Actionbent directly, one other bike manufacturer (E-recumbent manufacturer), one small specialty show producer, and a number of engineers as well as various web site and on-line forum owners looking to do something with my design. But, so far, nothing has come of any cantacts made.

That is no big deal, though. I am used to it. I went through this when I developed my first complete RC helicopter. Many contacts are made and very little ever comes of it.

Anyway, I am just finishing the last few detail bits on the bike before I stop development.

#1 The primary belt still skips at one specific RPM. It is annoying me. Under that RPM or above it, no skip. But, right at that point, it skips. I am moving up to GT2 power grip belts and pulleys.

#2 The stock disc brake is innadequate for anything over 25mph. It stops, but not with much authority and it fades if pushed really far. I ordered a 203mm disc to replace the stock 160mm disc. It should be here today.

#3 I need a 150 amp Eagle Tree data logger. I fried my 70 amp unit. :wink:

Beyond that, I would love to weld together some cool looking racks for carrying this and that. I will probably weld together some piano wire "Baskets" (very cool looking small racks on the left and right of the bike under the seat off the rear stays).

Oh, and I need that current limiter. That will be a nice touch.

Matt
 
recumpence said:
I am moving up to GT2 power grip belts and pulleys.
Click to expand...

Good move. I'm using PowerGrip GT3 belts, which seem to be the best you can get in 5mm pitch. You might also investigate 5m PolyChain belts, which are available (in limited sizes) in the US, but not in Europe :(
 
GT3 only seems to be available in Europe, at the moment (in the same way, the Carbon core belts were only available in the US :roll: )

Let me know if you need a European source for GT3 .

The 5M PolyChain series appears to be "orphaned"...

The problem with moving to 8M is that the smallest recommended pulley size is 22t (so that is all that's available from stock). I had an 18t one made, but you can't get anything like the ratios that you can with 5M (practically).
 
Gotcha.

What I need is a 14 tooth (5mm pitch obviously) aluminum motor pulley with 8mm bore (or smaller that I can bore out to 8mm on the lathe) and a 48 tooth aluminum pulley. 9mm wide is that I have been using, but I could go up to 15mm. I do not think I will need to go that wide, though.

Matt
 
I use a Goodyear kevlar belt that I got from McMaster-Carr on my Zappy. The Goodyear belt performs much better than the stock Gates HTD belt. Much less skipping and lasts much longer. The sprocket on a Zappy motor is a 13t 5mm x15 wide with a 8mm bore, made of steel. Aluminum sprockets in the smaller sizes (under 20t) do not last long. You might be able to find Zappy sprockets somewhere.
 
Tooth profile is the same (it's never changed from the original GT spec., for this case), so GT2 pulleys are all there is...

As for GT3 belts, I get mine here: http://www.beeline.co.uk/ They will split off any width belt you want, so no need to stick to 9 or 15 if it doesn't suit.

Miles
 
Give me a brake! :mrgreen:

I have been having brake fade issues along with a lack of brake power overall. So, for $21.99 on e-Bay, I picked up a new 203mm disc (stock disc is 160mm). The braking is fantastic now! One finger moderate pull is all that is required and I have wonderful brake feel as well as no more fade.

I am thrilled!

Matt
 

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Hi Matt,

Nice disks - i had the 160mm cable disk brakes and also found that with the extra weight of the bike they weren't sufficient to pull up quick enough, quick change to 203mm and hydraulics left me with the one finger levers actually being able to stop me dead, with one finger!!!
I think for any ebike thats fast and weighty hydraulics are essential!!1

cheers

D
 
I still have the mechanical caliper with the 203mm disc. It works fine. However, hydraulics would be better. I juts wanted to see how well a larger disc would work before dropping coin on hydraulics.

So far, so good!

Matt
 
woah!!!

i just noticed that matts are cable - thats one hefty cable shroud!!!
on the upside of cable at least they are easier to adjust rather than bleed hydraulics!!!
i found with my cable 160mm that i would suffer fade?


cheers


D
 
I get very little lever buzz with the 203mm disc versus the 160mm. I actually like the feel of this brake.

I have stayed away from hydraulics primarily because I do alot of work on my mountain bike with it upside down along with hanging it from the ceiling and I was told the fluid will leak out of the system is upside down. So, I went with Avid mechanicals on that bike and have never looked back.

Thsi bike is different, though. I may go with hydraulics eventually.

I also want to figure a way to get a disc brake on the rear. Not an easy proposition with a double chain system. :mrgreen:

Matt
 
I am thinking about using the RC technology and doing a single stage reduction. The motor would have a 12 pulley and the 5/8" jack shaft a 72 pulley. For the freewheel the adapter http://www.staton-inc.com/Details.asp?ProductID=2500from Staton should work. With the adapter you could use a right side freewheel and drive the wheel on the left or right side. No need for a BMX hub.

Matt- Where did you get the blank pulleys?

Bubba



recumpence said:
What I really need to do is develop a single stage reduction unit that incorporates the BMX rear hub with freewheel in a design that is easily manufactured. One thing that is surely required is the current limiter I mentioned earlier. I have actually shredded a 15mm wide 5mm pitch belt with this thing.

Even with all this abuse, the motor, controller, and pack all run nice and cool. :wink:

Oh, the primary belt skip I have been fighting seems to be related to the motor RPM creating a harmonic resonance that makes the belt vibrate and slip on the motor pulley. It is a neusance, for sure. But, it is liveable for now. It only happens right at a specific RPM. At that RPM, I get a bit of motor buzz, then teh belt skips (if under alot of load), then I move the RPM a touch past that point, and it won't skip no matter how hard I push it.

Weird.

Anyway, that is the last technical bug to work out.

The clutch is a God-send.

Matt
Click to expand...
 
That would work fine. So would a single stage reduction using the BMX hub as the jackshaft. But, you are stuck with the left side drive in that case.

I get all pulleys and related materials from SDP/SI (stock drive products).

Matt
 
My new 15mm wide GT pulleys and belts arrived today.

I will be at the shop tomorrow doing some machining. I will also be updating my clutch with different friction material.

I will post updates as I have them.

Matt
 
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