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  1. #1
    Beicwyr Hapus Gerryattrick's Avatar
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    Home-made 3-wheel tandem?

    This bike has come up locally for sale. I've never seen a three wheel tandem before and it looks a little bit awkward to ride safely to me.

    $_86.jpg
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  2. #2
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    That looks awesome and relatively well done. The weak link is often the attachment points that keep the bike from spinning in the middle. Also getting them to line up correctly so they track straight is easier said than done. I would totally rock that bike. I'd imagine turning in a confined space or while going slowly is.... difficult.

    Also, better hope the axle on the center wheel is strong.

  3. #3
    rebmeM roineS JanMM's Avatar
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    Trying to decide if that looks more stable than a typical tag-along for kids. I think it does, but a lot would depend on the details of the extra pieces that appear to have been added to beef up the connection between front and rear bikes. Three wheels but not a trike......hmmmmmmmm.
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  4. #4
    Senior Member CliffordK's Avatar
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    Quote Originally Posted by corrado33 View Post
    That looks awesome and relatively well done. The weak link is often the attachment points that keep the bike from spinning in the middle. Also getting them to line up correctly so they track straight is easier said than done. I would totally rock that bike. I'd imagine turning in a confined space or while going slowly is.... difficult.

    Also, better hope the axle on the center wheel is strong.
    I can't see the details of the attachment.
    I would assume handling would be awful if there was no natural pivot in the middle.

    I'm having troubles envisioning how the middle headtube angle would affect steering.

    Flex from a ball joint might be best. Without flex, one might get a teeter totter going over hills and bumps, and loose front traction in valleys and across ditches.

    While I would allow a pivot, I don't think I'd give the rear rider steerable bars.
    Last edited by CliffordK; 01-20-16 at 03:17 PM.

  5. #5
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    I am not taking it for granted that people will realize that the bike in the rear must allow the headset to function normally. I am therefore not understanding the function of the small piece ot tubing that runs from the fork of the rear bike to its downtube. Delta trikes often can be linked through a clamp on the rear axle of the leading trike that allows a second trike clamped only by its front dropouts to follow along. That is the principle behind the bikes linked above. IMO it should work just as simply. No extra reinforcements neeed be made except the ones that allow the rear axle of the leading bike to accept a second set of dropouts and hold them securely. Strength of the rear axle of the leading bike is a non-issue. I tow a trailer with my bike that puts far more stress on the rear wheel/axle than this thing ever will. The drawbacks as I see them is that the weight of the rear rider is high up. In the case of a 'stoker' with balance issues it would make for interesting handling. And the rear rider will need to be familiar with and able to operate the gear system. Food for thought. Thanks Gerry.

  6. #6
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    Quote Originally Posted by CliffordK View Post
    I'm having troubles envisioning how the middle headtube angle would affect steering.

    Flex from a ball joint might be best. Without flex, one might get a teeter totter going over hills and bumps, and loose front traction in valleys and across ditches.

    While I would allow a pivot, I don't think I'd give the rear rider steerable bars.
    Looks like we posted simultaneously. Agree with a lot of your points. Because I own a Bob Yak which uses a similar principle, I can explain why "flex" (ball joint) isn't necessary. The trailer has a "headtube" and it has a much steeper angle than most bikes. That said, I don't think it matters a lot. The trailer dropouts pivot up and down, around the rear axle and this allows the trailer to track over bumps and dips in the road independently of the bike. Bending right and left is accommodated by the trailer headtube. I wouldn't give the rear rider steering either, but you can see why things are left the way they are. The complexity of the project would become extreme if the builder decided to take on all the issues that have been raised here.

  7. #7
    Senior Member CliffordK's Avatar
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    Quote Originally Posted by Leisesturm View Post
    Looks like we posted simultaneously. Agree with a lot of your points. Because I own a Bob Yak which uses a similar principle, I can explain why "flex" (ball joint) isn't necessary. The trailer has a "headtube" and it has a much steeper angle than most bikes. That said, I don't think it matters a lot. The trailer dropouts pivot up and down, around the rear axle and this allows the trailer to track over bumps and dips in the road independently of the bike. Bending right and left is accommodated by the trailer headtube. I wouldn't give the rear rider steering either, but you can see why things are left the way they are. The complexity of the project would become extreme if the builder decided to take on all the issues that have been raised here.
    Your Yak pivots at the bicycle axle and at the headset.

    The one photo above isn't clear, but it appears to to have a bar from the chainstays on the front bike to the fork on the rear, and from the fork on the rear bike to the downtube. Of course, it is possible that one or both of those are flexible, or not attached on both ends.

  8. #8
    Beicwyr Hapus Gerryattrick's Avatar
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    This looks like a botched attempt to try out a tandem. It looks as if both "halves" of the bike have front and rear derailleurs and both have a rear brake!

    The seller is asking for 80 for it and I doubt he'll get anyone mad enough to buy it. He is well known for selling cheap bikes at a local market, but he knows absolutely nothing about bikes - just buys for next to nothing and aims to make a quick profit. His favourite selling line for his bikes is they have "front and rear brakes". This time it's three brakes on one bike!

    I think the joins between the bike are solid, and not pivots. Here is a pic from a slightly different angle, not very good quality.

    $_86-1.jpg
    Last edited by Gerryattrick; 01-20-16 at 04:20 PM.
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  9. #9
    Senior Member CliffordK's Avatar
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    That middle bar may also be a moderately flexible plastic fender. It looks a bit more fender-like from that second photo.

    Anybody making a bike like that may have very little welding/machining access. In fact, the fork may simply be bolted to the rear wheel, in which case, one should probably stop every mile or two to retighten the nuts.

  10. #10
    Beicwyr Hapus Gerryattrick's Avatar
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    It would be interesting seeing it go over speed bumps - and we have hundreds of those locally.
    A bike is for life, not just for Christmas.
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  11. #11
    Senior Member zonatandem's Avatar
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    An attempt to build a 'wannabe' tandem . . . looks a bit dangerous.

  12. #12
    Senior Member dwmckee's Avatar
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    There is a very good reason it is the only one you have seen...

  13. #13
    Senior Member dwmckee's Avatar
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    Hopefully they broke the mold after making it...

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