Beefing up a Warrior build?

Joined
Jan 28, 2015
Messages
15
Location
Colorado
Background: I already have a trike I love that I use for regular riding, but I want to create a fat tire tadpole I can use as a base vehicle for mobile sculptures - basically an "art trike". This will be something that will generally be used on the flat, and not at higher speeds - honestly, 15 mph is probably much higher than I'd ever be riding.

What I do need is the ability to carry more weight. I'm 275 pounds by myself (trying to get lighter), but to give me some room for sculptural additions, leds, batteries to power them, water, a bit of cargo, and so forth I'd like to have capacity for up to 400 pounds (including me). Probably would never get that heavy, but if I overbuild I have room for error or just to play with.

I'd also like to extend the steering arms a few inches, to widen the wheel track. That would compensate for the larger wheels so I can turn a little tighter without rubbing, and give me a little more leeway in terms of center of gravity. Neither fitting in a bike lane nor getting through residential doors is really a concern.

The Warrior seems like a good base to start with, especially since it can already handle 300+ if 14 gauge tubing is used. But since I'm shooting for a significantly higher weight capacity, and longer steering arms would add more leverage against the welds where the steering booms connect to the center tube, I assume I'll need to beef it up further.

The question, then, is how best to do that. I can think of a few approaches:
  • Standard 14 gauge build, with triangular gussets reinforcing the joints. Not sure how I'd add vertical strength where the steering booms meet the center, though.
  • Standard build, but using 12 gauge.
  • 14 gauge, but with a rectangular tube (perhaps 1.5"x2"), oriented vertically. This would give more vertical bracing where the steering arms attach, but would probably require a modification to the steering rod spacing to pass under the boom.
  • 14 gauge, but a bigger tube - maybe 1.75" or even 2". Seems like this might cause weirdness joining to the head tube and bottom bracket, since they are smaller in diameter.
Given the intended usage and the amount of room for improvement in taking weight off the engine, I'm not sure how much the weight really matters. But looking at metalsdepot.com, here's roughly how I think each option would affect the frame weight (not including seat, tires, components, etc), for the roughly 11 feet of tube in a standard Warrior build:

DimensionGaugeper footper 11 feet
1.5" square161.2613.86
1.5" square141.6718.37
1.75" square141.8820.68
2"x1.5" rectangular141.9020.90
1.5" square122.0722.77
2" square142.1423.54

I'm thinking retaining the standard 1.5" square dimension and going to 12 gauge might be the simplest option since it doesn't change any base measurements. But even there, I just don't have a good enough sense for material properties to know if that would be strong enough, or whether it's actually overkill.

Anyone have any thoughts on the best approach here?

- Eric
 
Joined
Apr 16, 2017
Messages
198
Location
Winnipeg, Manitoba
Not exactly a response you are looking for but here goes anyway. I used the the 16 gauge 1 1/2" tubing on my warrior. My weight at the time was just shy of 200 lbs. After a the initial rides to de-bug it and get everything set up a 500 watt rear hub motor plus a roughly 12 lb battery was added to the mix. It was great for casual bike path rides then a friend and I went for a longer ride that included some minor hills and quite a bit of gravel. On one stop on a small uphill when I tried to get going the trike sagged, the junction of the main boom and the rear forks - the metal actually tore, the weld held but not the tube. The Warrior got trucked home and I used ratchet straps to line the frame up then added 2 tubes, one per side where the metal had torn. Then 2 pieces of chainstay from the scrap pile were added as a triangular brace from the underside of the rear forks to the main tube. Just to be extra cautious a 1/16" plate was added to the top of the frame where the main boom and the steering arms attach. It has now been several years and about 4,000 km's with no further issues. My vote would be for the 14 gauge as well as some extra gusset's
 
Joined
Apr 15, 2013
Messages
1,785
Location
Washington state
go with the 14g but build with the cross beam on the bottom instead of the top. Will interfere with USS steering or go with BKS ( knuckle steering). Maybe look at using 1 inch box but build a ladder frame. A ladder frame is stronger but slightly heaver. + lots more work BUT it looks more like art.
 
Joined
Dec 29, 2016
Messages
194
Location
Lanc's, England
A alternative to the warrior is a python trike.

Mine and stormbirds pythons.
By making the python longer and wider you can get a flat load area to suit your needs.
If you make the rear frame encapsel the rear wheels you can use standard hubs.
Both pythons on the picture uses 12mm rod ends for the pivot point and 20" wheel,
but 24" works ok and if you are 6' or above you can use 26" wheel.
It's a more unusual design which make you noticed.
The younger generation often says "that's sick" when they see me.
I presume it's a compliment, but maybe I'm wrong?
 
Joined
Oct 19, 2012
Messages
434
Location
Wakefield, UK
Give or take a good meal we are a similar weight. I've built trikes out of 40x20x1.5mm steel and had no issues which is lighter than 1.5"x16SWG square. If you add suspension at the rear it will have the effect of damping out some of the loads taken. If you can add most of your extra weight further back the front boom joints will take less stress than if that weight is forward. For 400LB I'd opt to use 40x20x2.0mm. Almost all forces are in the vertical even in hard cornering so whilst easier to cut and measure I find square to be sub-ideal. If you pass the axle under the front boom you'll have the option to brace it from above though watch for USS issues. Any such bracing or gussetting isn't going to form anything but a shallow triangle - not an ideal brace but better than none. I'd suggest though that as Hugh found out the weakest point is probably the rear forks to boom joint so either gusset / brace that or use suspension. Even with rear only suspension some of the force of hitting a pothole will be transferred to the spring rather than the joints.
 
Joined
Jan 28, 2015
Messages
15
Location
Colorado
Thanks for the advice - sounds like 14 gauge and gussets are the simplest way to go, though the idea of the rectangular profile still intrigues me. Maybe that'll be the Mark II version.

My wife is lobbying for a sociable for the same event, so some sort of Kyoto/Loderunner mashup is probably next in line before a second Warrior (or a first Python).
 
Joined
Nov 10, 2019
Messages
37
Location
charlotte, nc
personally I would go rectangular and thin gauge walls like 1.5x3". I think you get 3x stiffer when you double the height of the tube. maybe on just the main length of the bike.
 
Top