Recumbent - Tadpole Trike Build

Cross-posting to Framebuilder Forum

Okay, I've decided I want to try and build a 'bent tadpole trike - fall/winter project.

I've looked at tons of pics of trikes coming up with the vision for mine. I'd love to do a laminated 'Woodie' just because what I've seen look so darned sweet. But I'm going to settle for a metal build for now. I'm just trying to figure out CroMoly or Alum. I'm leaning to Alum but have yet to find any simple to follow guidance on thickness/weight/strength on choosing the materials. Any help here would be wonderful.

Weight/size considerations:
Me- Height 5'4"
Weight 160 lbs
x-seam 32"

Primary Use: Commuting - but I want to be quick. I carry about 25 lbs of stuff to and from work daily.

Frame Considerations: Tadpole
700c wheels
CroMoly or Alum???

I'm thinking of a 10-speed hub and maybe an over/under drive.

Any thoughts or recommendations would be appreciated.

I can't help you a lot...I do not weld aluminum. If you do. that sounds like the way to go. My aluminum Linear LWB is about a 3x1 inch aluminum rectangle tube and holds my 180 pound body...for what that is worth.
I have been thinking of making myself a tadpole when I find time.... I am more worried bout the Ackerman steering and angles, etc.
hope someone jumps in here with more info.

tad pole front wheel setup is just like a car setup so there is lots of info and design specs on the net. As you've seen from the pics of other sites and go to this link:

http://home.mindspring.com/~kb7mxu/

You'll see there are a million ways people have put a trike together. Also I believe that manufactures list their tube diameters, so that will give you an idea too. And realize (IMO) that the companies selling trikes tend to overbuild them.

My homebuilt design is a hybrid with alum tubing and parts and steel tubing from racing bike build kits (Rey 531) for prototype and modular design...at least for the prototype. But I'm doing all the machining and brazing. I have to pay for alum welding at $85 an hour.

Alum has the problem of being welded, and paying to get that done. My experience, there are good and bad welders out there. Then you'll need some sort of frame jig. Theres tons more stuff you'll run into during the build so be patient.

I'd recommend sticking with steel, and I'd try to aim for 1.5 or 1.75 x 0.035" chromoly tubing for the main crucifix. You're not liable to find anything thinner in those diameters. Aero tubing would be cool for the cross-member, if you could work it and afford it. The stays could be smaller, and maybe thinner walls down to 0.028" especially if you triangulate the rear section to the seat frame. There are two issues with aluminum: 1) it should be heat-treated after welding to restore the alloy's strength and 2) it has a finite work cycle - if it's allowed to bend, it will eventually break.

That's right, my second trike was all alum, with 700c rear wheel and 2 24 inch wheels up front, and I had problems with the BB shell welded to the main tube, the tubing a little ways from the weld started bending and I had to cut it off and get it rewelded with a reinforcing tube inside.

That's why a lot of home builts are made with steel. I'm going with 2 headsets for the front steering setup to keep it simple. You'll see a lot of big, beefy and clunky front wheel axle set ups, from rod ends to big bolts. I'm using 1/2 diameter Stainless Steel shafts to hold the front wheels. All three will be 20"

Thanks for the info. So far from the Framebuilders forum was "do you have the skills need to start with?". Ouch!

I don't intend on rushing the build. If I can have it on the road by spring I'll be happy.

I do kinda think commercially built bikes are made a lot beefier than really necessary as they are afraid of lawsuits.

Well I've been working on mine off and on for over 2 years now...mine is sort of complex with FWD, Front suspension damping and more. As long as you realize there will be some challenges. Skills are learned on the way. What framebuilder forum...here at bikeforums.net?

OK- have you ridden a commercial trike? Have you ridden several? It would be a shame if you spent a lot of time and money building a trike and it turned out you weren't happy with it for some forseeable reason. You should find a group that you can ride with to see what trikes you like and what you don't- the devil is in the details.

IMO, the only reason to build a trike is for the experience of building it. There's no way you could match a commercial trike for design, build quality, or component spec without investing double or triple the money, plus all the time spent building.

Anyway:
1. Tadpole designs are great and also simplify the use of conventional bicycle drivetrains.
2. 700C wheels are not good since they are not as rigid laterally as smaller wheels. Recumbent trikes put a lot of side force on the wheels, which is why they tend to use 20" or smaller wheels.
3. Aluminum requires a highly trained welder and post-weld heat treatment. Steel can be welded with home equipment with a moderate amount of practice.

If you still want to try, Greenspeed sells plans and the unusual parts for building a trike:
http://greenspeed.com.au/plans.html
Rickey Horwitz sells plans for his aluminum Spitfire trike:
http://www.hellbentcycles.com/

ain't that the truth! I spent 4K just on the lathe/mill setup as I wasn't going to pay $$$ for machining...course the lathe was supposed to be for "other" projects too.

checked your bikes link...yes the Vector is the one that all should be measured against.

ain't that the truth! I spent 4K just on the lathe/mill setup as I wasn't going to pay $$$ for machining...course the lathe was supposed to be for "other" projects too.

checked your bikes link...yes the Vector is the one that all should be measured against.

Yeah... IIRC, they built the frame out of 2" diameter seamed mild steel , AKA muffler pipe. It didn't slow them down!

http://home.comcast.net/~jeff_wills/vector/apvector.jpg

Thanks for all the input so far. Hearing the negatives on a mistake ins design (or anything else) I think I'll skip the Alum for this time around..... still working the thought processes.

Intrigued by your "laminated woody" statement. Do you have any pictures, you could post?

Intrigued by your "laminated woody" statement. Do you have any pictures, you could post?

I'll have to go hunting again.... I did have them.

Intrigued by your "laminated woody" statement. Do you have any pictures, you could post?

This is what I found with a quick search. I didn't find the one I wanted though. It was done up in a really quality finish job and shinny brass detail.... I'll keep looking for it though.

This is what I found with a quick search. I didn't find the one I wanted though. It was done up in a really quality finish job and shinny brass detail.... I'll keep looking for it though.

From a previous thread:

Sam Bennett makes a really nice series of wooden recubents. He laminates sheets of birch for the main board. These are called "buckboards" but it is really hard to find info on them:
http://www.recumbents.com/WISIL/whpsc2006/images/krause/IMG_1445.jpg
http://www.recumbents.com/WISIL/whpsc2006/images/krause/IMG_1444.jpg

I don't understand the urge for wood as a material for bikes...but me, I love machined aluminum stuff like vintage campagnolo

I don't understand the urge for wood as a material for bikes...but me, I love machined aluminum stuff like vintage campagnolo

The best of old Campy was forged then machined, but yeah... it's really pretty. That's why I built this bike: http://home.comcast.net/~jeff_wills/lightning/index.htm

Thank you for posting the pictures. I never doubted that a "laminated wooden recumbent" could be built, but I have never seen one or pictures of one. West System Epoxies is always showing examples of how their products are used, but this one was new to me.

Cross-posting to Framebuilder Forum

Okay, I've decided I want to try and build a 'bent tadpole trike - fall/winter project.

I've looked at tons of pics of trikes coming up with the vision for mine. I'd love to do a laminated 'Woodie' just because what I've seen look so darned sweet. But I'm going to settle for a metal build for now. I'm just trying to figure out CroMoly or Alum. I'm leaning to Alum but have yet to find any simple to follow guidance on thickness/weight/strength on choosing the materials. Any help here would be wonderful.

Weight/size considerations:
Me- Height 5'4"
Weight 160 lbs
x-seam 32"

Primary Use: Commuting - but I want to be quick. I carry about 25 lbs of stuff to and from work daily.

Frame Considerations: Tadpole
700c wheels
CroMoly or Alum???

I'm thinking of a 10-speed hub and maybe an over/under drive.

Any thoughts or recommendations would be appreciated.

You don't need cromo or AL, mild steel works just fine and is dirt cheap.

For a simple cross-shaped frame, 1.5" x .063" square steel works fine with a 1" x .063" crossmember. you can use 1.25" x .049" for the crossmemebr too if you want, but the 1" is mroe than strong enough.

Building a trike isn't hard, anyone could do it. You just need to build what you're building and not keep changing details and requirments. Don't expect to hit a homerun on the first build. It isn't necessary anyway. Keep it simple, and you'll finish it. Whatever you would like to change on the finished trike, change it for the next one and sell the current one. The next build will be faster, smoother and more to your liking. Learn to use search engines too.

http://fleettrikes.com/tthindex.htm

http://fleettrikes.com/brakes.htm#Trikeplans

I actually ran in to another 'bent rider here in town. Up till now I've haven't found any others. And guess what..... he builds trikes :) Course what he built is awesome! College student goin' to school in NC. He cruised up next to me yesterday with this electro-powered trike. Said he's had it up to 63mph! :twitchy: Holy Cow!

We pulled over and talked for 15 minutes or so. Then he left me in a cloud of dust on that hopped up powered trike. I sooooo want one now. :D

Time to knuckle down and get busy building my first. But looking at his frame gave me so ideas on my build.