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warren Posted - 11/03/2016 : 15:03:21
The gentle reader may ask, "Why don't you just pick a trike and ride it!". Oh, I have reasons gentle reader, reasons.

After riding and racing the Greenspeed Areo, I can say it handles corners well and is fast in a racing environment. I do not however fit in the seat as they are designed for "normal" height humans and major reconstructive surgery would need to be performed to make that happen.

After racing and riding the ICE Vortex (almost a VTX!) I can say that the seat fits me well and it is comfy, but due to a lack of triangulation it does not do well in a racing environment. The VTX is stiffer in the rear and has a seat which can be laid back more that the Vortex so it would be better, but is still has just a monotube and that will allow the rear wheel to deflect in the hard corners.

That leaves the Catrike 700 yet which I not raced or ridden in anger. It is however quite popular in the HPRA racing series. If I were to obtain one, it would need some modification including a hardshell seat to get me a bit lower, and probably a change to indirect steering. If my backside can fit between the seat rails they would make great side bolsters to prevent sliding off the seat in the hard corners.

The final option is of course, building one from scratch.

Here's my web page documenting my racing trike investigation and research.


So, What makes a recumbent trike fast? Build or buy?

25   L A T E S T    R E P L I E S    (Newest First)
warren Posted - 11/16/2017 : 10:29:06
More work on the kingpin assemblies - drilled out the axle hole to match the axle diameter, pressed the bearing races onto one of the head tubes, ordered 1-1/4x.058 tubing for use as bearing seats, found some sheet metal to use as shim between lower headset bearing race and the steerer tube. Now I have a complete assembly that I can use to make measurements to add the cruciform tubes!

Did the 1X cruciform drawing. Cruciform tubes will each be about 1ft long. These will be more tubing cuts that need to be right! The joint where the cruciform tube attaches to the head tube has to be angled in two dimensions, both kingpin inclination and caster. Fun (Not!) I think I'm going to cut the main tube at the point where the cruciform attaches to fix the boom angle. This will also allow me to attach the cruciform tubes together inside the main tube. Should be stronger and allow for some minor tweaking.
warren Posted - 11/13/2017 : 21:33:12
Brazed up the kingpins. I don't have a lathe so I had to fake it with concentric tubes. The holes in the sides of the tubes are to braze the axle tubes together. I was able to create the proper angle hole in the steerer tube with a 3/4" holesaw. Aaaand I'm out of acetylene.

Low tech construction pics:

The next trick is to make the seats for the headset bearings.

More here: http://www.recumbents.com/wisil/trike/default.htm

alevand Posted - 11/13/2017 : 10:32:50
Must be flexy if the trisled only weight 14 kG.
http://trisled.com.au/hpv/gizmo/" target="_blank"> br / http://trisled.com.au/hpv/gizmo/

Tony Levand
warren Posted - 11/13/2017 : 08:25:54
To save weight I'm going to make a CF tube for the boom that will bridge the gap between the cruciform area and the BB area. Otherwise I have to use the super heavy .049 wall 2" tubing. I can put a slight mitre in the CF tube. The CF tube will clamp over the 2" frame tubing so the boom will be removable. That way it will fit in my CRV.

A trike like this built from a bent tube would be very cool. I can bend the 1.5" OD tubing in the roller bender. How does Ben at Trisled get away with using 1.5" OD tubing to build his trikes? Are they flexy or does he just use thick heavy wall tubing?
alevand Posted - 11/13/2017 : 06:04:37
Are you using the boom off the donor bike? Its too short for the bender. I adjust frames by slicing the tube part way, near the joint, with a .030 cutting blade in the hand grinder, applying force to close it, cut again to get to close most of the way and weld it up. How hard it would be to redo the joint?

Tony Levand
Speedbiker Posted - 11/13/2017 : 00:07:42
Warren, run the boom through your tube roller!

Camber = slower.
warren Posted - 11/12/2017 : 14:57:24
The kingpin parts are cut and ready to braze. And I actually cut the angles right. Amazing.

No wheel camber, Tony.
Jerry Posted - 11/12/2017 : 10:25:13
Ha ha, I could lower the BB 3 more inches and still have heel clearance. I know the feeling Warren, been there, done that, way more than I want to admit! Looks like it will be a very fast trike though.
alevand Posted - 11/11/2017 : 15:57:48
Originally posted by warren

It took 5 hours to cut, mitre, jig, tweak and braze this joint. And it's off. How far off? Looks like the BB will be at 10.5" now. Hmm. 6" crank length plus 7.5" of shoe = 13.5" to the ground with foot hanging straight down at the bottom of the pedal stroke.

Hi Warren,
Ha, I know the feeling all to well. Maybe you can grind the heals off your shoes, or maybe the trike will do this automatically for you. Yes, foot is at about 45 degrees at BDC, so that would about be 3.5 inches clearance heal to road.

...Hopefully the spindles will turn out better with the fixture. Are planning any camber?

Tony Levand
warren Posted - 11/11/2017 : 10:03:55
It took 5 hours to cut, mitre, jig, tweak and braze this joint. And it's off. How far off? Looks like the BB will be at 10.5" now. Hmm. 6" crank length plus 7.5" of shoe = 13.5" to the ground with foot hanging straight down at the bottom of the pedal stroke.

Apparently my plastic angle measuring tool is not good for low angles.

Fortunately your foot doesn't normally hang straight down at the bottom of your pedal stroke. I measured on my bike and it looks like I need about 10" of ground clearance while pedaling normally. Hmm. I'll try it and have to tweak it a bit if it's not enough clearance.
warren Posted - 11/08/2017 : 15:16:10
Yes that would be a good change John, but that's part of my donor bike. Do I really want to rebuild the rear end of the trike. Umm...
Johnsfwdbent Posted - 11/08/2017 : 13:02:23
Warren, looks good! how about moving the main tube up tighter under the seat!
Johnsfwdbent Posted - 11/08/2017 : 12:53:53
Warren, looks good! how about moving the main tube up tighter under the seat!
Speedbiker Posted - 11/08/2017 : 11:53:27
Do like Brauchler and add foam+carbon fairings to your tube frame.
warren Posted - 11/08/2017 : 08:08:51
When you already have a donor bike and a seat languishing in storage, yes it's easier. I decided I need to build the steel version first and tweak it before committing it to full carbon.

I cut a bunch of tubes last night.
alevand Posted - 11/08/2017 : 05:41:42
Hi Warren,

Is it that much harder to fair the boom into the seat, than to fab round tubes?

Tony Levand
Speedbiker Posted - 11/07/2017 : 21:13:48
warren Posted - 11/06/2017 : 10:58:48
1X drawing is done. 44" wheelbase. 5" seat height. 14" BB height. Looks cool. Trying now to figure out if I can fab up a CF tubes that will clamp over my 2" tubes so I don't have to use heavy 2" x .049 tubing for the boom and bottom tubes. I bought some shrink tube sleeves to compress the CF layups evenly.

warren Posted - 11/04/2017 : 23:02:29
Yes, 3 - 20 inch wheels. There are no 4 wheel racers in the US. Govt. does not consider them bikes...
carolina Posted - 11/04/2017 : 17:14:29
Warren, your trike will be three 20’s?


Have you ever seen 4 wheeler racer? Would it have any advantage?

Speedbiker Posted - 11/02/2017 : 11:20:36
I look forward to seeing it. Very few custom racing trikes are built. I have some great ideas, but have too many other projects.
warren Posted - 11/02/2017 : 10:47:31
The 8020 that Carolina uses is indeed impressive, but is out of my price range. I'm going to build an adjustable fixture out of wood, which will bolt to my bike fixture. The 1.25" OD alignment tubes will be able to be pivoted and bolted tightly in place. I'll post a drawing in a few days. I'm working on the 1X drawing of the trike now.
carolina Posted - 11/02/2017 : 02:05:59
I like that s. American catike dude somehow: but Ian Sims better! He has put breath back in me (“ in my life on email”) when no other Americans would. Its a rare individual.

Speedbiker Posted - 11/02/2017 : 00:06:16
Warren, what kind of fixture do you plan to use to align those spindles or headtubes(steertubes) when you braze them? That stuff Carolina uses is very tempting.
warren Posted - 11/01/2017 : 11:33:01
More specs for the steel racing trike:
* Same geometry as the discussed CF tracing trike
* The main trike frame will be steel (street racer).
* Front Sturmey Archer drum brake wheels from tilting trike
* 1.5" cruciform tubes
* CF hardshell seat
* 3/4" seat support/triangulation tubing from rear stays to cruciform, running on outside of CF seat ribs.
* The boom will fold to allow easier transport.

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