Warrior trike build: weight -vs- strength testing

S

Simon

Hellow fellow zombies!

I'm in the middle of making a warrior trike, and it's a whole load of fun! My first every metal working project too! look! Isn't she a beauty?

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I've been looking around on this forum as well for inspiration and possible pitfalls, all super interesting.

One thing I noticed is that some people on the forum are adding extra bits and bobs to strengthen up the frame, mainly the rear fork and the side arms. That sounds pretty smart, but it is adding more and more weight to a steel frame that is already pretty heavy...
I was wondering if anyone has done any weight-load testing on the frame to determine how good/bad the welds are? (me being a rookie welder, that might go both ways...) and wether I should reinforce the frame... I figured: my weight (80-ish kg) devided over 3 contact points, would mean the rear fork should be able to take MINIMUM 28kg, same as each individual side arm. Adding a safety factor of maybe 2 (?) should give me some viable numbers to work with ... I think? Anybody have any experience with this? Is safety factor of 2 reasonable, for when I go over a bump at speed? How do you know what safety factor you should pick?

Thanks for the help!
Simon
 
We have seen many examples of the Warrior trike having a stress-fracture/break at that rear joint if there is no triangulation back to a main frame member.
Usually for either or both of the following 2 reasons.
  1. The rider is more than a trifle "overweight".
  2. The rider adds a mid drive motor of excessive wattage and the pull of the chain tries to fold the frame up.

It is not a bad design at all, but does benefit from the added triangulation.

Enjoy your ride. :)
 
hmm. I dont count myself in the trifle overweight cathegory (grin), but I do recognise the drive motor part. That is a plan of mine for sure. I will have to consider that! thanks for the tip!
 
I am guilty of being overweight AND pedaling too hard in the "wrong" gear. First I bent the square tubing around the rear fork welds... then the frame started to fold up as Danny said.

I had to cut off the rear weldments and replace them. During the repair I added tubing to triangulate forks. Yes, it added weight but it was clear in my case that if I didn't make a correction the same failure was going to happen over and over again.
 
I'd suggest anyone, regardless of weight or welding ability, reinforce that area. The reinforcement tubing will be in perfect tension (ie not in use as a beam) so can be very lightweight. Alternatively if you don't want the visual look of a diagonal tube there you could gusset the joint, effectively adding a lot of extra weld length to share the load. A pair of triangles about 3" on each of the sides getting welded should do though I'd add that the tubing diagonal will be a stronger solution.

As to safety factors, try about 40x. The maximising factor is hitting a pothole at speed. This can impart shocks of around 40g on a bad one without getting silly extreme. The first one may not get you or the tenth but it will tear at the weakest point over time. The actual figure you get will of course depend on factors such as tyre size and pressure as well as whether the pothole gets through the tyre to the rim. You should find about 2/3 of your weight is over the front wheels so the rear is lightly loaded. This helps but that 40g figure is the elephant in the room.

BTW that light loading makes having a rear brake very much a dicey proposition. In a corner and braking your weight will come off that rear wheel making it much more likely to lock up. When it does that it will overtake the front very quickly. Fun if you are intending to do it. Not fun otherwise. I'd suggest front brakes only from solid experience. With one front brake per lever you can also use the brakes to tighten the line in a fast corner should you get in too fast.
 
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I agree completely with Popshot.
His G-force remark is what gets most people. But a decent bump in the road, and your tires are the first line of "dampening", then inertia takes over, unless suspension is in play.

Brad designed the Warrior to be an agile, reasonably weight road machine, but with modern tech, adding a motor and batteries, using the lightest , most grippy and lowest rolling resistance tires, the concept will be stressed.

On brakes. Forget the back wheel as a braking wheel. (I have a disk brake on my rear wheel, and it's parking brake). The only thing it will do is lock up at any speed above snail.
And yes, I used seperate front wheel brakes, changed that to 1 lever brakes, and went back to 1 wheel 1 brake.
The dual brake handle is fine, if you have only 1 hand to squeeze. But seperate gives you a lot more control.
 
Maddox, could you send me pictures of your rear/parking brake? My current setup has cable actuated disk brakes with locking levers. I have been considering switching to hydraulic disk. If I make that change I will need a different parking brake setup. Thanks for any pictures and/or advice you can offer.
 
Not much to show actualy. The setup I currently use is a Tektro BB7 and a 160mm disk on the rear hub. The brake "lever" is actualy an old school shifter without indexing.

I started with 2 Tektro BB7's in front, with locking levers. Changed that to a double lever on the right, and a single left, with the double doing the 2 front brakes, and the lefty for rear (140mm centerlock and a very budget friendly "RED" ). I learned then that the rear brake is a parking brake, nothing more, nothing less.

I changed then to pure parking brake in the back. And double lever right for the 2 front brakes. Works. And if you start from the Double setup (like my wife) you don't want to change.

But if you know the comfort and fun of independent front brakes....

So yes, if you can handle hydraulic disks, do so for the front.
If hydraulics ain't your thing, enough mechanical options. From the cheapest Chinesium "RED", to the most complicated double 2 sided mechanical caliper systems.
 
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I'd absolutely recommend hydraulic over cable if you have the funds. I got some Chinese M4 4 piston ones for about £45 a pair. They were very good and looked great. The downside is there aren't any left / right pairs I know of unlike with cable versions. That means left and right get mounted diffrently with different hose routing. That may bug you or it may not. Bigger discs make modulating the power easier too but they do add a weight penalty which given the use is probably not necessary unless doing serious downhilling. As said a friction cable shifter makes a good parking brake.
 
I definitely agree that hydraulic brakes are the dogs-dangle's/mutt's-nuts for awesome stopping power. An order of magnitude over cable disc brakes.
What we need now are Hydraulic drum brakes so we can avoid all the rust and dirt and the like. Seems counter intuitive I know, but we aren't doing 90MPH in cars.
 
Now you mention it it does seem odd that nobody does them. I wonder if anything could be retro cobbled on to an existing cable drum! There are some rim brakes that are an amalgum of cable and hydraulic. That may be an option.
 
Thanks for all the advice and observations about the hydraulic brakes. My apologies to the OP. I didn't mean to hijack your thread.

Fast for me is 25 mph downhill. My cable disk brakes can handle that without issue but the cable routing causes so much friction that the right brake lever requires significantly more squeeze effort than the left brake. I just have too many bends and too many brake cable noodles. My hope is that the hydraulics will allow for more balanced braking.

I was considering Shimano BR-MT201 hydraulic brakes as they are quite affordable and a name brand.
 
Wow, this thread picked up some speed! Love it! Thanks for all the input! since most of what we're talking about is still in the future for me I'll take all of it to heart!

@Popshot: damn 40G sounds alot, but I guess it does make solid sense. Last time I hit a pothole with my skinny-tired racing bike at speed it did not end well. Good thing the wheels I'm going for on the trike are somewhat more solid. Looks like I'm gonna have to look at reinforcing that rear fork joint for sure, seems like we're all in agreement on that one.
Anybody heard any failures on the side arms? any need to reinforce those as well?

Also great input on the break layout. I have no experience with 3 wheeled breaking strategies, so this is super interesting.
I figured most of the weight goes on the front wheels, so my plan A was indeed setting up breaks on the front only (a happy coincidence since the rear wheel I started with has no disk setup). One break handle per wheel, because even tho I feel that one handle for both wheels would give me a more predictable behaviour under breaking, I feel it would require too much force on one hand to break both wheels comfortably.
This question does change abit when we're talking about hydraulic breaks tho. Ever since I got hydrolic breaks on my day to day bike I just fell in love with them. The feel of them is so superior to cable breaks I dont want to go back. So maybe I might try a hydroulic one lever breaking both front wheels, because of the soft feel of the hydroulic system one lever two wheels shouldnt be too
Sadly they do come with the problem of theft tho. very popular with bike thieves. I'll have to make sure I pull the cables through solid loops in the frame.

@dannyD: Havent tried drum breaks on any bike. The only reason why is that I feel I couldnt do the service in case it went wonkey. Do you guys have any good experience?

On the topic of break levers and such: Which way are you guys mounting break levers? are you guys mounting your levers upside down (cable pointing down, breaking with pinky/ringfinger) or rather the same way as ordinary bikes (cables pointing up, breaking with index). I'm used to a index/middle finger breaking, but I dont want my cables all over the place either...

Haha, I forgot about handbreak. Not really a problem on my day-to-day twowheeled bike :D
I was thinking of some kind of custom solution of a rod mounted on the rear fork that you can click in/out inbetween the spokes of the rear wheel in a clever way. Havent given it too much thought to be honest.

Thanks for the help!
Simon
 
We've seen the odd weld give way on the side arms but that's usually more to do with a bad weld or two than any inherent design flaw. I'm a fatso and no similar failure has happened to me.

Brake levers usually go upside down so 4 finger levers are best so you aren't just getting the little fingers on them. The issue with one lever and two calipers on hydraulic brakes is one of master to slave piston ratios. Manufacturers have spent a lot of r&d money on getting the ratios right and T ing off a second slave to the same master will bugger that ratio royally. There are only two ways I can see to do it.

  1. Rig up one lever operating two masters.
  2. Mix and match with say a 4 piston lever and two piston calipers. It won't be right as 4 piston calipers generally have smaller pistons but it may be closer. You need to get piston sizes to compare them all ideally.
Handbrakes are damned useful for getting on and off, particilarly on a slope, so having one you can set / unset whilst seated is useful particilarly for those of us getting on in years. Whippersnappers may find one superfluous. It'a long way down there and getting further every year.
 
I chose twist shifters for my build. To fit them I had to mount the brake levers such that the brake cables and levers pointed down.

I bought an inexpensive disk brake kit from Amazon which has worked well... apart from my cable routing creating too much friction on the right brake cable. Soon after fitting the brakes I ordered different brake levers which had a locking/park pin. The levers themselves provide my parking brake function.

Maddox, thanks for the nod on the 200 series Shimano brakes.

I have one more comment on the brakes. If you choose off brand components, take a close look at their design. Try to select disk brakes that use pads that fit Shimano or other name brands. That should insure you can buy replacement pads when necessary.
 
I recently installed Shimano M820 brakes. Insanity.... On dry asfalt, I go nose down. But those ain't Atomic Zombie style....
 
I'm a little late to the party, I've built 3 warriors and a tomahawk and I reinforced the rear wheel supports on all four and the front wheel arms on the warriors. I didn't do any kind of stress test or weight testing, I was more concerned with the frame holding together long term more so than being as light as possible. I'm not anywhere near the weight limit and don't plan on doing any off roading or making it an E bike, but here was my reasoning:

I considered trying an aluminum to cut weight, I ruled it out when I realized store bought bikes have a 5 year warranty on aluminum bikes and lifetime on steel.
Other people on here have had the rear wheel weld have issues and are likely more experienced welders than I am.
I'm new to welding, the first warrior I built was my first 'real' welding project.
I didn't see any 'real' trikes/bikes with a single support for the rear wheel, however the rear supports were fairly 'skimpy' in comparison to the main supports, so I opted for 1" tube. The tomahawk I used the front wheel forks from the donor bike.
A single point of failure is a major risk in my opinion, with multiple points if one fails, you'll have more of a warning than a serious incident.
While I'm not overweight, I do have fairly strong legs and was concerned how similar riding a recumbent feels to a leg press machine and it seemed like the majority of the pressure peddling would be against my back and directly into the rear wheel weld.
Ultimately I would be more upset if the trike broke while my g/f or mother were riding them, than if the final product was a pound or two heavier.
 
Lots of info here! Very useful, thanks!

@Thom_G Yes, I have been looking at your builds, and they are one of the reasons why I'm asking this question. I cant really argue with your logics. Better to add abit of weight to keep it alive, then having a slightly lighter bike that will break two months into the stint.
Also, thanks for the documentation of your builds, I have been studying your approach to solve tricky linups and angle work. They really helped me out: much appreciated!

Do we know of anyone who has made one of these in aluminium? Maybe slightly tweaked the design of that rear joint? I'm tempted to have ago as well, but i havent even finished my first build, so should probably finish one before I start a second one. :D But it should be doable, no?
Reason I'm thinking so much about the weight is that frensh guy who made the mosquito velomobile, bringing the weight to 10kg ish by using airplain building technieques with wood, foam and aluminum. It's so increadibly inspiring to see, and you can only imagine how much more fun a lightweight bike is to ride.
But the design is completely different compared to the warror, so it would be quite a project to translate one into the other. hmmm. quite the project...
 
I have only built the one trike. Were I doing this again I would look seriously at melding the rear end of the Street Fox to the front end of the Warrior. My trike will rattle your bones when going over street cracks and potholes. I also wonder if the pivoting rear end of the Street Fox would make it less prone to damage from the high stress on the Warrior.
 
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