Wheeled vehicle construction (cont from tracked thread)

[capjbadger]

Badger, I respectfully disagree with you; you are not in over your head at all. You are learning, which is a highly legitimate process! A few years ago I was scared of bicycle crank sets. Now I can tell you which brand is built to the closest tolerances (Schwinn -- in the realm of old thrift store bikes).

To my mind, Side Load is what you feel when you drive around a corner in a car. (Car racers talk about "side bite', meaning traction while cornering.) On a bike, you lean into the turn which eliminates the side load on the wheel, keeping the load at 90 degrees to the axle.

Were you talking about the kind of bicycle rear wheels that have gears inside the hub? The old Sturmey Archer 3-speed? I tried these -- made by Shimano in more recent times -- on The Two Ton Tricycle. Busted them all to heck in no time. (There are 7-speed and even 15-speed hubs now, but they are expensive.)

If I were to build some bicycle sandwich wheels, I think I would take the bearings out of the hubs and shove the largest possible (3/8?, 1/2?) steel shaft thru all the hubs. Then run that shaft in external bearings. Look inside a swamp cooler -- like the bearings the big squirrel cage fan runs in.

We could go on a long time here, and maybe accomplish something eventually! But I will be going incommunicado for a couple of weeks, starting tomorrow. And we are a bit off Jafe's original Tracked Vehicle... uh... track. Why don't you start a thread on wheel building and see who shows up!

Good idea. New thread started.

Yeah, I was thinking of using the standard back wheel and hub. But moot point since the tires can't hold up to my estimated weight of the vehicle. I was hoping to use the derailer like a manual transmission. Plus I'm not sure they could take the torque.

The more I think about it, the more I like the motorcycle tire idea (other than the extra it will cost me )
From what I've seen, they would be strong enough to take the torque, and should be able to handle the weight. Plus I know some run off of chain drives, which stays in line with the first idea. Now to figure out a transmission system to control speed other than just the straight throttle on the engine...

I know there has to be quite a few motorcycle buffs on here. You folks know what the weight limit for a motorcycle tire is?

Badger

[Gravity Mike]

Gents,

Concerning bicycle wheel load limits, also consider 'shock loads' as you hit bumps. If you just overload a tire to test it's limit, you can't load even up to 50% of that limit, or you'll taco on the first significant bump. I think these things are really overengineered with respect to static load so that they can handle the shock loads.

Concerning making the wheels stonger. I've been to Indonesia many times, and I learned something about making cheap old bicycle wheels really strong while over there - replace the spokes with REBAR! I'm not kidding, it's a standard 'vehicle' on the road over there: a two-bicycle wheel push cart (must be carefully balanced - like a trailer, but they push it) that holds around 14 or 16 containers, at least 5 gallons each. This is around 1000 pounds - on 2 bicycle tires with around 8 rebar spokes, holding up to pot holes and the like (needless to say, Indonesia roads suck). Obviously, you'd never go up, or down, a hill with this. I wish I had a picture...

BTW, I'm definately going to check out the Arcata/Ferndale KSR this year with some potential 'team mates,' and hopefully we'll race in 2007. Thanks for introducing me to this fine 'sport.'

Gravity

[Elliot]

.
Gravity: On the other thread you mentioned planning a railroad handcar type contraption. To my knowledge there has never been such a thing in the KSR. You would be a major hit -- no matter how well (or poorly) it worked the first time out! There is a lot of crossover between KSR and BM. It's a natural and it is why I'm here now. Don't forget costumes -- and bribes for the judges. Web site: www.kineticsculpturerace.org. The KSR museum in Ferndale is open year round.

Stout welded-in spokes are a great way to go. Tubing would be lighter than rebar. A friend of mine uses square tubing from junk office chairs and such.

I will be out of town and incommunicado a week or two, but I WILL be back. Build something in the meantime!

[Elliot]

Oh, and folks who show up here looking for some serious wheelwrighting will want to see this:http://www.scrye.com/~hersh/ksr-entry/

I'll let you know when my other favorite wheelwright gets his site back up.

Build something. You can make it actually work later!

[capjbadger]

Gents,

Concerning bicycle wheel load limits, also consider 'shock loads' as you hit bumps. If you just overload a tire to test it's limit, you can't load even up to 50% of that limit, or you'll taco on the first significant bump. I think these things are really overengineered with respect to static load so that they can handle the shock loads.

Concerning making the wheels stonger. I've been to Indonesia many times, and I learned something about making cheap old bicycle wheels really strong while over there - replace the spokes with REBAR! I'm not kidding, it's a standard 'vehicle' on the road over there: a two-bicycle wheel push cart (must be carefully balanced - like a trailer, but they push it) that holds around 14 or 16 containers, at least 5 gallons each. This is around 1000 pounds - on 2 bicycle tires with around 8 rebar spokes, holding up to pot holes and the like (needless to say, Indonesia roads suck). Obviously, you'd never go up, or down, a hill with this. I wish I had a picture...

BTW, I'm definately going to check out the Arcata/Ferndale KSR this year with some potential 'team mates,' and hopefully we'll race in 2007. Thanks for introducing me to this fine 'sport.'

Gravity

Hmm... I like. The math is a bit off though. 5gal*8lbs*15containers=600lbs not 1000lbs, 300lbs per tire safely, which is still far better than the 75-100lbs per tire we were talking about earlier. Perhaps 2 sandwiched wheels each for the fron (for a total of 4) and a single in the back. 5 tires, 1500lbs safe limit, vehicle weight very roughly guessed at max 1000lbs, = an extra 500lbs leeway on the load limit.
Boy do I like... I'll have to look around for some pics of those carts.

I'm just starting to teach myself welding for this. Is it possible to weld steel (rebar) to aluminum (bike wheel) with a arc welder? Or at all for that matter?

Badger

[Elliot]

Sorry, so far as I know, steel and aluminum can not be welded together. But you don't need to. Steel rims and hubs are plentiful and don't weigh much.

Word is, a wire-feed welder (MIG) is the easiest to learn and not expensive.

I use a "stick" arc welder, but it is a rather crude tool, tricky on thin materials. (I burn a lot of holes!)

Top of the heap is a TIG (tungsten) welder, but those are expensive and require more skill. This is the only realistic way to weld aluminum, though.

[capjbadger]

Nuts. They make steel bike rims and hubs? Cool. I'll have to head to the local recycle center with a magnet...

I picked up a 250 amp arc stick welder. I have lots of scrap to practice on. ;D

I was looking at flux core wire feed MIGs, but didn't have the money for them.


Badger

[capjbadger]

Yay! I think I may of hit on a good way to do this. Digging around the net, I stumbled on trailer tires! 590 to 910lbs each as far as the load capacity, and they're only about 25 bucks a pop. I think this might work.

*thinking out loud* Hmm.. Back steer wheel free spinning, front axle welded to the wheels and a bike sprocket welded to the axle for the drivetrain and derailer for shifting...

[Elliot]

Recycle - good
magnet - yes
practice - you bet
lack of $ - normal
trailer tires - try local industrial supply stores and tool stores (like Harbor Freight) also. Those tires seem to be everywhere these days, complete on wheels.
Thinking out loud - yep, that's what we do here.

Axle welded to both wheels - bad. If you attach both wheels to a one-piece axle, you may have trouble making the Silly Thing turn.
Easiest fix is to split the axle in two and have each rider drive his own side. Or you can use a differential from an old lawn tractor. These can sometimes be had free at mower repair shops and private parties after the engine dies.
Either way you would need two extra bearings, but that is really not much of an obstacle.

Progress in your planning - impressive.

[capjbadger]

Each rider? Ahh I see the confusion. This isn't pedal powered, it's powered by a go-cart engine. I wonder if having say just the right front wheel powered and the left front free spinning would work, or if it would pull to the right...

A differentail would be nice. I'm trying to keep things fairly simple for my first MV

Badger

[capjbadger]

Ooooo!! New idea...

*breaks out the erector set again to build it for testing...*

[robotland]

It'll probably take another year or two for them to start trickling out to yard sales and flea markets, but the recent popularity of custom choppers has prompted the bicycle industry to produce bikes with fat back end and big tires that'd be awesome to play with. I've seen a few unmodified ones on the playa already. Just can't bring myself to buy a bike off the rack, though. The best bikes I've ever had were under five bucks, and I've been collecting dollar-specials from the thrift store for my current project.

[Elliot]

Engine - OK

Single wheel drive -- should work OK on the playa. It will pull a little, but not enough to worry about.

The current flood of toy motorbikes and "chopper" bicycles and such crap (sorry, Mom) from China - I have friends who are currently chanting the phrase "...will soon enter the Waste Stream."

Must run

[dragonfly Jafe]

...as far as shock loading, mountain bikes get a SEVERE shock load and do OK...(at least I have never taco'd a tire mountain biking). You could use a forked-style holder for each wheel on the back (just like the front) to support both sides of the wheel axel, but you will still get some side loads. I wonder if you could allow the rear tires to pivot 5-10 degrees and relieve the stress in turns without loosing too much efficiency? Probably make the drive train too complicated...

...as far as weight, 500 lbs was common on the ho-chi-mihn trail, so I would say at least 250lbs per tire should be OK assuming you use good quality mountain bike parts or better. You could push that if you don't mind eating into your safety factor (and don't travel too fast). You will probably get some indication you are near the limit - load it up and be observant. Reinforce what breaks. Post the results. Repeat.

[capjbadger]

...as far as shock loading, mountain bikes get a SEVERE shock load and do OK...(at least I have never taco'd a tire mountain biking). You could use a forked-style holder for each wheel on the back (just like the front) to support both sides of the wheel axel, but you will still get some side loads. I wonder if you could allow the rear tires to pivot 5-10 degrees and relieve the stress in turns without loosing too much efficiency? Probably make the drive train too complicated...

...as far as weight, 500 lbs was common on the ho-chi-mihn trail, so I would say at least 250lbs per tire should be OK assuming you use good quality mountain bike parts or better. You could push that if you don't mind eating into your safety factor (and don't travel too fast). You will probably get some indication you are near the limit - load it up and be observant. Reinforce what breaks. Post the results. Repeat.

Saw this while digging around.
http://www.northerntool.com/webapp/wcs/ ... 026&R=1026
300 lbs. Not bad, but the trailer tires seem to be a better choice at this point.

Badger

[Gravity Mike]

Badger wrote:

Hmm... I like. The math is a bit off though. 5gal*8lbs*15containers=600lbs not 1000lbs...
Badger

Give me a break Badger, it's called ballparking!! Like, is it ~100 lbs, ~1000 lbs, or ~5000 lbs. I stick by my guess. The math is crap cuz all the input was guessed. My (indonesian) wife says 12 containers; still don't know the size of the containers, but > 5 gallons each is what she says (of course, there are no 'gallon' size containers there - it would be metric). I say no more than 10 gallons. Even with this info the best you can do is a factor of 2 of the true weight, cuz I still don't know the container volumn. Anyhow, I digress, these wheels are strong...

I found a picture of a push car with rebar spokes on the net (but hauling tires). It's more like 16 spokes - I guessed 8 or 12 I think. Let's see if I can get this thing up.



Gravity

[capjbadger]

Sorry. Wasn't trying to nitpick or anything.

Wow... Now that's a tire! (the irony that he's carrying a load of tires is not lost on me either. lol)

[Lassen Forge]

Those wheels are common, tho originally they had wooden spokes. The one in the picture uses solid steel round stock, tho I've seen them built with pipe as well.

You can still get the tires (and the wheels) through people who wither sell parts for pushcarts, or people who sell parts for old cars. Be warned tho - the tires are like $125 each (they're now handmade in, of all places, viet-nam - no joke!) but for this kind of use will last through 20+ BRC's on an art car. The rim is 23", the tires run 70 PSI, and actually lock into the tire (or vice versa) through a pair of beads on the tire...

Ford used this same tire, tho with a wooden wheel, on the Model T - and he made 15 million of those.

And they're rated at something on the order of 500-750 lbs each. Getting ideas yet?? >grins<

bb sue,
erstwhile old car nut.

[Gravity Mike]

We're cool, Badger.

BBSue, yeah, that tire does look manufactured! However, I recall seeing them improvised with rebar - with that unmistakable grippy texture. I'm suggesting 'reinforcing' mtn bike tires. Probably not as stong as the manufactured ones, but probably alot cheaper if you can weld and can get cheap old bikes.

Gravity

[Lassen Forge]

It's not just the wheel that has to hold the weight - it's the tire as well.

Even if you reinforce the hell out of a bicycle wheel, you're limited by how much weight the tire can hold up without flattening itself out.

Maybe using a 26" or 20" bike tire with enough pressure would work. I'm just windering by the time you go thru all that, maybe it'd be cheaper and more sane to co to a motorcycle salvage yard and buy some cheap used bike wheels with tires on it. You put more than a couple hundred pounds per wheel on bike tires, they won't take the weight, even if the wheels are strong enough.

bb

[Bob]

Two-wheel concrete carts like this have been around a long time, though rarely used since concrete pumpers w/ booms became more common. AFAIK most take 4x18 tires, and the capacity is about five to eight cubic feet (up to about a half ton). Similar wheels are used on other types of hand-transport carts. Spokes are probably ~1/2 inch round bar, and the hubs are ~2 inch heavy pipe.

http://www.garbro.com/dump%20carts.htm

[dragonfly Jafe]

It's not just the wheel that has to hold the weight - it's the tire as well....You put more than a couple hundred pounds per wheel on bike tires, they won't take the weight, even if the wheels are strong enough. bb

...and if you could reinforce the tires (say, fill with expanding foam) then the bearings will fail. And if you reinforce the bearings, then maybe the sprocket or chain would fail. Or maybe the frame. Everything must be reinforced that bears any extra load...

[Gravity Mike]

Some good points all around. I guess it depends on how much you plan on exceeding the original rating - if it's worth fortifying or getting something stronger. I like the motorcycle wheel idea especially. I wouldn't worry about bearings too much, as I would maybe put 100 miles/year an any mutant vehicle (unless I really abuse them, of course).

I've seen people pair up bicycle tires too. On some surfaces it could be nice having the big footprint, like on sand.

Gravity

[robotland]

[quote="dragonfly Jafe...and if you could reinforce the tires (say, fill with expanding foam) ..[/quote]

Great minds stink alike! Have you tried this? I was also looking at the "no-flat" hard foam tires that they make for garden equipment...Too expensive, though. Something makes me think that having the pneumatic cushioning on the hard playa is worth bringing spare tubes and pump.

I started on the frame for the "dung beetle" yesterday- It's a modified 2V geodesic that sits on a rectangular or triangular frame. (I'm trying both, mocked up in wood for stability tests before I go welding on the scrap bedframe steel for the final...) Already I'm making plans to ditch the heavy 1/2" EMT for hybrid struts salvaged from old tent poles. My trusty old playa bike does NOT like the way I'm looking at it....Like in the old cartoons, where everything looks like a rotisserie chicken when you're hungry. It might have to surrender its drive system.

[dragonfly Jafe]

...fortunately I was gifted 2 cheapo mountain bikes in 2003 by a couple who bought them in Reno and just wanted to get rid of them to a good home...unfortunately they are probably too cheap to be of much use - still, they make excellent visual aids and toys to play with!

The tongue may have seen it's last burn however. Talks from the Creator are heading in the direction of a motorized couch conversion, maybe. Or not. But I cannot take both the tongue and a bike-thingy, so....

[capjbadger]

Hmmm.. I think I've solved one of my problems with the whole 3 wheel setup. Right now the setup is basicly a backward tricycle, with the steering tire in back.
My current idea is to attach the engine on the fork of the back wheel so that it is the steering and the drive wheel and I don't have to futz with any crazy drivetrain linkages.

Has anybody tried this sort of thing? Would this work?

[Gravity Mike]

Has anybody tried this sort of thing? Would this work?

I can't say I've tried it, but it sounds like it'll work to me.

I'm trying to make a similar, but pedal-powered, vehicle: reverse tricycle with drive in back, but I'm going to make the front two wheels steer. My problem is welding, I'm still totally incompetent (and can't spell either)!! I've got this small 90A wire welder, maybe it's not big enough, but I know I wont' get a 220V outlet in my garage anytime soon so this is what I got to work with for now.

I gotta get my act together and build me one of the kinetic sculpture racers!

Gravity.

[Tiahaar]

I've got this small 90A wire welder, maybe it's not big enough...

hey yes, big enough for 1/16 or even 1/8 steel tubing (even bigger if multiple passes and v'd joints are done). Spring for a good weld helmet though...those cheapie handheld toys that come with some budget welders are just useful for an observer. I too have a little flux core MIG that is super on clean tubing with close fitting joints. Interesting steering idea you have! When I was a kid I had a sit-down trike where the back two wheels steered with a joystick while you pedaled the front, was way fun.

[dragonfly Jafe]

cheap welder OK

cheap welding helmet not OK (took me 2 years to learn this)

spend the extra on those instant on/off lenses, they at least triple your work speed and greatly improve your quality...

[capjbadger]

Interesting steering idea you have! When I was a kid I had a sit-down trike where the back two wheels steered with a joystick while you pedaled the front, was way fun.

You mean the old Green Machine? I love that thing. Looks like they've brought them back!