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Thread: An electric Bike called "Fein": Made in Africa

              
   
   
  1. #31
    Senior Member Hugues's Avatar
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    Quote Originally Posted by Diethelm Rust View Post
    Hugues!

    At the moment I am at 1:6 so it should have lots of torque and I want to start of riding slow to get the feel for the bike. Might change the front 24 tooth [144 rear] to a 26 or 27 if higher speeds are required at a later stage.

    For your e-cruiser are you opting for a belt or chain drive?
    1:6
    cool, that's what I need too. At the moment i'm using a 530 chain and 13 tooth drive sprocket and 80 something at the back. But it's noisy.
    I remember asking about belt drives ratio and i was told 1:6 is impossible.
    Where did you buy the belt and pulleys ?

    What's the max torque they are rated for ?

    that looks very good !
    Regards from Switzerland
    My 2.5 Upgrade Thread

  2. #32
    Member Diethelm Rust's Avatar
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    Quote Originally Posted by Hugues View Post
    1:6
    cool, that's what I need too. At the moment i'm using a 530 chain and 13 tooth drive sprocket and 80 something at the back. But it's noisy.
    I remember asking about belt drives ratio and i was told 1:6 is impossible.
    Where did you buy the belt and pulleys ?

    What's the max torque they are rated for ?

    that looks very good !
    Noisy and eventually oily. Don't want that either.

    1:6 is very possible. I will manufacture the pulleys myself in our machine shop at the company I work for as they will have non standard features, especially the rear pulley. The front pulley I was able to find online from several resellers:

    http://www.gg-powertransmission.com/timing-belt-pulleys/htd-8m/ which is a company in Germany. But even these need to be bored out and keyed to fit the shaft. Timing pulleys are sold standard with a pilot centre hole and then modified to fit.

    For that reason I chose to make both pulleys from a 30mm 6 series aluminium plate. The tooth profile will be CNC milled and after that the pulley bore is turned using a CNC lathe to get a perfect round bore.

    Timing belts are rated for power transfer as the torque transfer capability is inverse proportional to the rotational speed of the smaller pulley in your system.
    I found some high power transfer belts locally [South Africa], up to 18kW and I think that the short burst of higher power should be lower than the FoS of the belt. The belt I will be using is 25mm wide, kevlar reinforced.

    Goodyear and Opti Belt make high power transfer belts.

    Hope this helps!
    -------------
    The Helm

    “My project was retarded by laws of nature. The world was not prepared for it. It was too far ahead of time. But the same laws will prevail in the end and make it a triumphal success.”
    ~Nikola Tesla

    http://www.evalbum.com/4510

  3. #33
    Senior Member Hugues's Avatar
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    Quote Originally Posted by Diethelm Rust View Post
    ...I found some high power transfer belts locally [South Africa], up to 18kW and I think that the short burst of higher power should be lower than the FoS of the belt. The belt I will be using is 25mm wide, kevlar reinforced.

    Goodyear and Opti Belt make high power transfer belts.

    Hope this helps!
    thanks for the link, i sent them a mail,

    as for power, i need 50 kw, have you seen anything in this ball park ?
    Regards from Switzerland
    My 2.5 Upgrade Thread

  4. #34
    Moderator ZoomSmith's Avatar
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    The tooth profile will be CNC milled and after that the pulley bore is turned using a CNC lathe to get a perfect round bore.
    Do you have access to the tooth profile geometry?

  5. #35
    Member Diethelm Rust's Avatar
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    Quote Originally Posted by ZoomSmith View Post
    Do you have access to the tooth profile geometry?
    Yes, I do. Check out Traceparts Online and search for "HTD 8M" or "HTD 14M". Bobs your uncle.

    I then went ahead to makes sure that the geometry is true
    -------------
    The Helm

    “My project was retarded by laws of nature. The world was not prepared for it. It was too far ahead of time. But the same laws will prevail in the end and make it a triumphal success.”
    ~Nikola Tesla

    http://www.evalbum.com/4510

  6. #36
    Member Diethelm Rust's Avatar
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    Quote Originally Posted by Hugues View Post
    thanks for the link, i sent them a mail,

    as for power, i need 50 kw, have you seen anything in this ball park ?
    Not for 25mm wide. The wider you can go [on your e-cruiser there should be space?] the more power you will be able to transfer. Power transfer is directly proportional to the belt width.

    If you don't find a 50kW capable belt, Go for something smaller. It might not last 5 years but it will do the trick.
    -------------
    The Helm

    “My project was retarded by laws of nature. The world was not prepared for it. It was too far ahead of time. But the same laws will prevail in the end and make it a triumphal success.”
    ~Nikola Tesla

    http://www.evalbum.com/4510

  7. #37
    Moderator ZoomSmith's Avatar
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    Yes, I do. Check out Traceparts Online and search for "HTD 8M" or "HTD 14M". Bobs your uncle.
    Great Link! Unfortunately nothing for Gates GT2 profiles (my belt).

  8. #38
    Member Diethelm Rust's Avatar
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    Quote Originally Posted by ZoomSmith View Post
    Great Link! Unfortunately nothing for Gates GT2 profiles (my belt).
    What is the tooth pitch for your GT2? Maybe I can find something for you. Also what number of teeth are you looking for front and rear?
    -------------
    The Helm

    “My project was retarded by laws of nature. The world was not prepared for it. It was too far ahead of time. But the same laws will prevail in the end and make it a triumphal success.”
    ~Nikola Tesla

    http://www.evalbum.com/4510

  9. #39
    Moderator ZoomSmith's Avatar
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    Pitch = 8mm, Front = 28 Tooth, Rear = 140

  10. #40
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    Quote Originally Posted by ZoomSmith View Post
    Great Link! Unfortunately nothing for Gates GT2 profiles (my belt).
    The HTD belts and sprockets are an older design with ~ 1/3 to 1/2 the load carrying capacity of the more modern Gates(as one example company) Poly Chain GT2 and Poly Chain GT Carbon belts and sprockets. This is why Zero can get by with a skinny 14mm(?) wide Poly Chain GT Carbon belt. To add more confusion, Gates is phasing out the Aramid fiber(Kevlar) Poly Chain GT2 belt line in favor of the carbon belts.

    The HTD and Poly Chain(PC) designs are not normally interchangeable. Although, I've heard some people get away with it in light load and test applications. The tooth profiles are different. Also, from what I've heard, the patent for the PC tooth profile has recently expired. So, it may take some hunting, but the machining info is probably out there somewhere if you want to make your own sprockets.

    Of course, this is for only one manufacturer in the U.S. Other companies might very well have their own standards. I try to stick with one company for the belts and sprockets unless I can directly eyeball the fit. It's difficult to tell the types of sprockets apart. In my shop, I lightly paint the PC sprockets with gold paint- very appropriate because they cost considerably more than the HTD sprockets!
    Last edited by Fab man; 01 May 2013 at 2024.

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