Recumbent - Possible to connect a delta to a tadpole?

Does anyone know if its possible to connect a delta trike to a tadpole trike. I know that delta are often connected together using the hitch by Hase, but I am thinking that it might be possible to simply put the front fork of the delta on the outside of the rear dropouts of the tadpole. I would imagine that the fork would need to replaced or custom build to have a wider spacing.

This way the rear wheel of the tadpole would essentially also be the front wheel of the delta trike. Does anyone know if this is possible?

Thanks

If you are replacing the fork to fit..... I don't really see why you couldn't do it. But my question would be why? In order to have a "tandem"? I'd think you would loose a lot on weight and efficiency over a tandem. But what the heck, if you have both it would be cheaper than getting a tandem.

You'd probably have to replace the wheel on the delta with a much beefier one since it would have a lot more weight and side-ways torque put on it.

Your two immediate problems are:

1) If the tadpole rear wheel has symmetrical dishing.
2) The different dropout spacing for a front fork and a rear wheel.

If the first is true, then it will be impossible without modifying the tadpole frame or the delta fork (or both). The second one is does not have an off-the-shelf solution that I know of so it too will require some custom fabrication.

:)ensen.

It would actually be to make a triplet, adding it to a tandem trike. I know I could have 3 deltas hooked together, but I would definetly prefer the efficiency of a rigid tandem. I also plan on making a full fairing so that we can take the tandem trike in the rain and cold.

The reason for the above desire to connect to a thrid seat is:
Currently, I have a DF tandem and triplet. My daughter and I ride a lot on the tandem. I pick her up from school on the bike whenever the weather is right. I really want the tandem trike to help my stokette be more comfortable and to create an all-weather velomobile. But... I don't want to leave my wife totally on her own. She doesn't ride a single person bike (although she has never ridden a trike) and only rides the triplet for a week long tour each summer, and a few training rides before and after that. She still wants to ride with us on those occassions, but also wants my help pulling her along.

I would love to sell my tandem and my triplet and buy a tandem trike plus a delta type single trike. This would allow for all of the configurations I would ever need. Of course the three person would be extremely long, but that's alright, I'm sure we could manage just fine. After all, I already have the experience of riding an 11 foot long triplet with a cargo trailer attached.

Delta hitches provide the second degree of freedom that you need as the rotate about a horizontal axis in line with the direction of travel. (The headset provides the other degree of freedom). Connecting a delta to the back of a tadpole as has been propsed would not work because there would only be one degree of freedom (the headset only).

Delta hitches provide the second degree of freedom that you need as the rotate about a horizontal axis in line with the direction of travel. (The headset provides the other degree of freedom). Connecting a delta to the back of a tadpole as has been propsed would not work because there would only be one degree of freedom (the headset only).

The hitches need to allow 3-axis motion.... imagine climbing a hill, then making a U-turn at the point the grade changes. So, not only does the hitch rotate in line with the front-back axis of the lead trike but also allows the attached fork to rotate around it's drop-outs. The headset of the towed trike provides the 3rd axis of rotation.

:)ensen.

Does anyone know if its possible to connect a delta trike to a tadpole trike. I know that delta are often connected together using the hitch by Hase, but I am thinking that it might be possible to simply put the front fork of the delta on the outside of the rear dropouts of the tadpole. I would imagine that the fork would need to replaced or custom build to have a wider spacing.

This way the rear wheel of the tadpole would essentially also be the front wheel of the delta trike. Does anyone know if this is possible?

Thanks


It would mean custom work of some sort- either a complete custom front end on the delta along with a custom hitch, or a custom hitch hung behind the rear wheel of the tandem. The latter would require less work, but the weight distribution will be weird.

I've seen towbars for tadpole trikes, but I can't remember who makes them. There was a mention on Bentrider recently... and it appears their search function is broken right now. Grr...

Is there any reason why you want a tadpole tandem in front? Delta trikes seem to be made for "trains". There was a 4-Kett train at this year's Monster Cookie ride, which got along just fine:

http://vimeo.com/4382706

Keith and Alex Kohan (in the red, white & blue Randonneur USA jerseys behind the Kett-train) rode their Ketts on several long tours, including across Oregon on Cycle Oregon 15. They kick butt- but then both of them are ultra-randonneurs, capable of riding 500 miles in one stretch.

The hitches need to allow 3-axis motion.... imagine climbing a hill, then making a U-turn at the point the grade changes. So, not only does the hitch rotate in line with the front-back axis of the lead trike but also allows the attached fork to rotate around it's drop-outs. The headset of the towed trike provides the 3rd axis of rotation.

:)ensen.

What you are saying makes perfect sense. However, I know the Trizard and Anura hitches do not have the freedom for the stoker trike fork to rotate about the dropout centers as the Hase hitch does. I kid you not, the Triz hitch has, by itself, only one degree of freedom. I have not noticed and negative effects when riding with my wife hitched on the back of my Trizard. And we ride very rugged terrain too. Need to hitch them together and then lift the trikes up by the hitch and see how this works. It hurts my head just thinking about it.

I think the most straightforward approach would be to substitute a new front fork on the delta with the dropouts spread wider than the rear dropouts on the tadpole. This could be accomplished relatively cheaply by scavenging a donor bike.

Using the original fork with 100-mm spacing would be a problem, even if you fabricated an adaptor, because that 100-mm width would interfere with the back wheel and nearby frame members. I suppose if the adaptor pushed the delta's fork rearward of the tadpole's dropouts a fair amount, you'd avoid this, but that sounds like it would be tricky to rig in a way that would be sturdy.

Jeff Wills: In the answer to why not just use a train of kets. The main reason for the desire for a tandem trike is mentioned above, to create a fully enclosed velomobile. It might be possible to cover almost all of the delta seperately and hook them together. I've never seen this, but it might be possible. The problem would be the hitch area. They could not be enclosed in one body because of the bending in the middle.

Steamer, its nice to know that it *might* work. After hearing the logical points made above, I also thought about putting some sort of bearing on either side of the drop out. I think this would allow for the necessary movement. The only axis that wouldn't have movement would be the twisting motion, but I don't think this would be an issue (seeing how none of the other connectors address it either).

I think I'm going to try it if I ever get one. The problem will be trying to find or make a 20" (or close to it) fork that has about a 145mm spacing.

Ok. i did the quick and dirty experiment, and it was indeed revealed that the fork is just rotating directly on the hitch "axle" without the benefit of the nice bushings that are incorporated into the Hase hitch. Bearings or some kind of simple bushing sure would be a better arrangement. Bottom line there needs to be rotational freedom in all three axes. Two isn't not enough regardless of which two are chosen.

Good call Jensen

Jeff Wills: In the answer to why not just use a train of kets. The main reason for the desire for a tandem trike is mentioned above, to create a fully enclosed velomobile. It might be possible to cover almost all of the delta seperately and hook them together. I've never seen this, but it might be possible. The problem would be the hitch area. They could not be enclosed in one body because of the bending in the middle.


OK- I missed the part about the full shell. Yoicks, that's going to be something! I helped out on the Left Coast Velomobile Gathering (http://www.flickr.com/photos/wmbates/sets/72157618744819975/)last May, and we had one of everything... but no tandems! Here's a couple links that might help:

Cargo tadpole towing another tadpole (BentRider thread, scroll down a bit): http://www.bentrideronline.com/messageboard/showthread.php?t=54543
Basic shell that can be added to a tadpole (stretch it a bit for a tandem): http://www.velocityvelos.com/
Delta-style velomobiles: http://velomobiles.ca/
A Screamer tandem with bodysock, raced at PIR in 2004:
http://homepage.mac.com/joeygrimaldi/.Pictures/Photo%20Album%20Pictures/2004-06-03%2001.02.18%20-0700/Image-24E9B5BAB53311D8.jpg

I think I'm going to try it if I ever get one. The problem will be trying to find or make a 20" (or close to it) fork that has about a 145mm spacing.

Barcroft made a 135mm spacing fork for their FWD Oregon lowracer. I think they're sold out, but there was a mention of BentUp Cycles having a few more made. It might be worth a try.