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-   -   Home-made 3-wheel tandem? (https://www.bikeforums.net/tandem-cycling/1045753-home-made-3-wheel-tandem.html)

Gerryattrick 01-20-16 11:27 AM

Home-made 3-wheel tandem?
 
1 Attachment(s)
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.

http://bikeforums.net/attachment.php...hmentid=499428

corrado33 01-20-16 11:42 AM

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.

JanMM 01-20-16 03:04 PM

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.

CliffordK 01-20-16 03:13 PM


Originally Posted by corrado33 (Post 18473223)
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.

Leisesturm 01-20-16 03:24 PM

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.

Leisesturm 01-20-16 03:35 PM


Originally Posted by CliffordK (Post 18473763)
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.

CliffordK 01-20-16 04:02 PM


Originally Posted by Leisesturm (Post 18473831)
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.

Gerryattrick 01-20-16 04:16 PM

1 Attachment(s)
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.

http://bikeforums.net/attachment.php...hmentid=499477

CliffordK 01-20-16 04:27 PM

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.

Gerryattrick 01-20-16 04:35 PM

It would be interesting seeing it go over speed bumps - and we have hundreds of those locally. :eek:

zonatandem 01-21-16 11:11 PM

An attempt to build a 'wannabe' tandem . . . looks a bit dangerous.

dwmckee 01-27-16 10:41 PM

There is a very good reason it is the only one you have seen...

dwmckee 01-27-16 10:42 PM

Hopefully they broke the mold after making it...

Binky 03-28-16 06:11 PM

2 Attachment(s)

Originally Posted by dwmckee (Post 18492450)
Hopefully they broke the mold after making it...

Still not the worst offender:

I picked up a three-wheeled tandem a few years ago and did not expect to see a reference to another.

This was also a home-built monster.... but had lots of really good parts so I bought it anyway.

Before and after pix attached. The before picture is off the ad and really low quality !!

Lucky for me -- the conversion was simply bolted-on and the frame and rear drop-outs were not damaged.

http://bikeforums.net/attachment.php...hmentid=512208http://bikeforums.net/attachment.php...hmentid=512209

dwmckee 03-29-16 08:31 PM

Well, at least with the original post I can see the advantage of no arguments between stoker and captain about what gear to be in! That brings Independent Pedaling Systems (IPS) to a whole new level...

ksisler 04-04-16 07:06 AM

If the price was low, I would buy it, take it apart and add back the front wheel to get two bikes out of it.

Monoborracho 04-04-16 03:47 PM

One of these days I figure we'll be riding one of these.
http://myweb.tiscali.co.uk/trykit/Ga.../images/04.jpg

CliffordK 04-04-16 04:59 PM


Originally Posted by Monoborracho (Post 18663729)
One of these days I figure we'll be riding one of these.
http://myweb.tiscali.co.uk/trykit/Ga.../images/04.jpg

Sweet looking ride. I wonder how it corners though? Inside rear off the ground?

I might think of migrating to something like a tandem quad recumbent.

https://s-media-cache-ak0.pinimg.com...a137fe5ba9.jpg

Or, maybe a side-by-side, but the tandem would be more appropriate for road riding.

Darth Lefty 04-04-16 06:25 PM

My wife and I saw a rig like that going up the trail this weekend, or it might have been a tadpole. I've been encouraging her to try a bent due to her back problems but her sense of dignity hasn't let her yet.

CliffordK 04-04-16 08:55 PM


Originally Posted by Darth Lefty (Post 18664121)
My wife and I saw a rig like that going up the trail this weekend, or it might have been a tadpole. I've been encouraging her to try a bent due to her back problems but her sense of dignity hasn't let her yet.

You could get one of the hybrid tandems.

http://www.pedersenbicycles.com/imag...viewpoints.jpg

Darth Lefty 04-04-16 10:03 PM


Originally Posted by CliffordK (Post 18664473)
You could get one of the hybrid tandems.

Dignity, I said!

CliffordK 04-04-16 10:08 PM


Originally Posted by Darth Lefty (Post 18664581)
Dignity, I said!

Who's dignity? Put the boss in the lounge chair up front!!!

They have one of those upright/recumbent tandems at the local co-op. I've heard people saying that it is great fun after a test ride.


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