Wheel loads

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ferball

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Apr 8, 2010
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I am amassing junk bikes to begin my recumbent trike project. One bit of info I can not find anywhere is the max load capacity of the various size bike wheels. I realize that it will vary depending on quality of materials and such, but I was hoping to have some sort of base line to go by. If I use a 16 inch bike wheel from a kids bike will it hold up under my 300 pound load? How much will a 20 inch wheel take? 26 I was not to worried about as they are intended for "adults". Is this info even out there?
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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there are so many different wheel makers out there, from cheap toy bikes to ultra-high end race bikes that there isn't a standard chart. since bicycles don't need to meet any DOT or other standards, it would depend on the manufacturer.

that being said, heavy duty 20" rims are easy to find, just look for a good quality BMX wheel. you can still find older steel wheels with 12g spokes and heavy duty hubs. i had an old set of dimpled Femco rims which were as strong or stronger than any Worksman wheel. (worksman still has an 11g steel clincher, by the way.)

you could probably find a good quality set of 16" wheels, too. again, check with the BMX'rs. 16" pit bikes were really popular a few years back, and they made some pretty heavy duty stuff.

i'd stay away from the lowest budget kid's bikes if you're worried about strength, durability and safety. just looking at some of those wheels should be enough to scare you away. those bikes are designed to be disposable, since little kids outgrow them so fast, and the price is so cheap it's not even worth it as a hand-me-down. not to mention a 5 year old isn't gonna be putting much stress on it.

a well-built 20" wheel can take more abuse than a larger, comparatively built 26" wheel, because there's less flex. it's a sturdier, compact design.
 

ferball

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Apr 8, 2010
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I am planning on using some "disposable" kid bike wheels for the mock up and concept and plan on upgrading if the design works out, but I want to be able to ride it a bit to test stability and steering a bit before putting real money into it, or deciding it is not worth doing. But having looked at them you are right in that just looking at them prompted the question. But I also know that they are going to be the two front wheels of a tadpole trike and my design should keep weight towards the back, so I was hoping somebody might have a rough idea of max load for a wheel. I mean it would be nice to know anyway as we tend to stop worrying about weight when we strap a motor on. More than once I questioned the durablity of my current wheelset and it was a decent mid level mountain bike in its original life.
 

glennbo

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Aug 24, 2010
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20 inch rim 30+mph add a pot hole or two you will have boken spokes i went through 5 back rims on my first 20 inch build
 

corgi1

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Aug 13, 2009
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maybe you could use a moped rear wheel and increase the rake(caster) so the front wheels get a straighter gravity load when in a corner instead of side loading (tilting trikes are good too)
 

ferball

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My next question is because I lack a budget, is there an easy way to reinforce wheels? Like beef up spokes or something? I have looked at moped wheels for a build, but it seems I would have to be dedicated to motoring as pedaling a moped tire would suck.
 

corgi1

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another thread in the last couple days envolved a 16 inch moped wheel and with the tire it was about 20 inches,it is built stronger but about the same size as a 20 inch bike wheel and was friction drive,looking at pics it is not much heaver than a bike wheel,and the purpose here is stronger wheels ,
Moped Army - Photo Gallery - 1983 AMF Roadmaster A110
these are not bulky,and if u found two ,there is a pair of stocky front wheels too,and an extra rear wheel
 

bairdco

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Aug 18, 2009
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search craigslist for used BMX bikes, or look for a bike store that specializes (or at least has a good selection of) BMX bikes.

i dunno what glennbo is talkin' about, he must be using some crap wheels. i used to build up 20" wheels for my bmx bike with thin 14g spokes, and a 5 cross "race lace" pattern (where all the spoke heads are on the inside.) it increased lateral stability, reduced hub flange stress, and they were indestructable. they woulda held up a truck if you could figure out how to mount them.

i mean, look at what BMX'rs do. jumpin', ridin ramps and skateparks, and just all around thrashing put a heck of a lot more load on a wheel than hitting a coupla potholes at 30.

(this isn't meant as a jab at you, glennbo, just sayin' you musta had some crappy wheels, or some giant potholes:))
 

BarelyAWake

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Jul 21, 2009
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I know you've mentioned this is a budget build, still... I figure rims are pretty important & if you can relace yer own rims something like these may be an idea: Alex 20x1.5, DA-16, Black Alloy Rim | BikepartsUSA I jus' ordered a set and was impressed by their overall quality for the money. Heads up tho, those rims I linked are 36 hole, which seems somewhat uncommon for that size...


The bigger problem w/using wheels from a "kid's bike" or even yer average "BMX" for a trike would be the hubs, I'm assuming you mean a 16-20" wheelset for the duals on your recumbent trike - in which case the axles are problematic as they're not designed to be supported from only one side. While there's some trike designs that do have support - those are kinda uncommon...

The common solution for DIY tadpole trikes is to use 20mm hubs, which allows a massive axle - easily made from a grade 8 bolt or w/e and plenty strong for single sided support with their large sealed bearings... they're not cheap tho, the best price I've found was about $35 each for "20mm Quando 36H" & again when I received them I was suprised by how nice they were but they seem out of stock everywhere ATM...

edit: saw yer makin' a taddy lol
 
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ferball

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I plan on using the forks for each wheel to avoid the hub problem and simplify the build.
 

BarelyAWake

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Yea - that defo helps a lot to keep it simple, including being able to use rim brakes - in that case I think bairdco's completely on the money, the smaller the wheel the stronger it is and jus' about any BMX wheel outa do well (^)

Can't wait ta see some pics man, ya got something yer usin' for inspiration?
 

ferball

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Apr 8, 2010
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A combination of the two pics below. I want a short wheel base, but keep my diamond frame for easy engine installation and for a higher seat for safety while driving around town. But use the Front end design and the underseat steering from the Long wheel base pictured to give me trike stability and keep my feet off the ground while stopping. Because my ultimate plan is to build a fairing for all weather commuting.
 

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corgi1

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I am thinking ,flags or lighting for visibilty to other drivers,drop the center of gravity back down low and the front cross axle can be what ever height depending on clearance,more caster so the wheels coroperate better at high speeds and reduce side loading on the front wheels in the turns, the long wheel base is good for stability at higher speed but makes for bigger radius turns, and the seat needs to go forward making the front to rear balance point further forward (like putting a 12 inch ball in your lap when seated on it)should be aprox. only 1/3 the distance from the front wheels center to the rear wheel center(between 66/34 and 70/30, rear/front),or 2 feet from the front ,4 feet to the rear,etc,larger upper body weight and thinner size legs(age,beer,etc)moves the center forward,,woman's weight distribution also moves it more to the 66/34 balance a little(hip and leg weight and less upper body weight)
 

ferball

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Apr 8, 2010
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I want to experiment with a narrow stance out front so I need to keep the front cross axle high to avoid rubbing. I realize my COG will be high, but lighting and flags does not make it easier for me to see things. But I did just pick up a potential donor frame to day, that would seat me lower and more forward if I can figure out engine mounting. But it is all still at the idea phase. hopefully saturday I can start chopping and mock something up.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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Sounds like an interesting project. Just to clarify something regarding the AMF pictures. I recently picked up a 1980 originally for the front fork and front drum brake, but now am going to put a china girl on it. The first photo of an 83 is very different from the second picture. The second one, like mine, was a rear wheel friction drive. The 83 was a more conventional moped design and used an Italian engine and chain drive. The older AMFs used a McCullough motor probably designed for a chainsaw. The wheels are nice with heavy spokes, rims and drum brakes. If you had two donors you could use the suspension forks and have suspension at each wheel up front, which might be an advantage. The drum brakes would give you a lot of stopping power. My wheels are 16" rims and with tires come out to a little over 20". I know you're probably going a different direction in wheels, but just thought I'd clarify a bit with the little I know about it. Good luck with your project!
SB
 

ferball

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Apr 8, 2010
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I have been looking at mopeds for wheels, I am planning on putting a trike together with the pile of parts I have, I have my choice of 16 or 20 inch in my pile of goodies. If the concept works out nice I want to put together a heavy duty version that will probably incorporate more moped parts for something I could use as a "daily driver".