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Arbo
03-10-2005, 08:16 PM
I am in the process of building a small replica of a very early car. Bicycle wheels will be on all four corners. I am sorta cheap, and got some free bike wheels. I have the rear figured out easy enough, but the front has me a bit concerned. My plan is to make spindles and a steering mechanism. The wheels I currently have for the front have an axle that is about 8.25mm. Do you think I'm asking for trouble by not having any outboard support on these spindles? I know that the bikes have the forks on both sides, and that makes sense, but I'm not sure about the wheel just running on a spindle that small. The majority of the weight will be on the rear axle. Top speed is planned at about 20MPH. A photo of the axle and bearing setup is below. The plan is to weld one end of this axle to the steering mechanism, install bearings, and hold the wheel on with the nut on the outboard side. What ye say...Yea or Nay?

http://img.photobucket.com/albums/0903/arbothor1027/projects/P3100006Small.jpg

ibewgypsie
03-10-2005, 08:59 PM
I don't think it'll hold. Of course I am a large man and break things other people don't.

There are pedal cars (scottish mail delivery) made with bicycle wheels. I wonder how they did it?

David

precisionworks
03-10-2005, 09:14 PM
Some motorcycles use a single-side swingarm. Those that do go much bigger in diameter than the conventional axle that's supported on both sides. Is it possible to obtain larger ID bearings so you could use a larger OD axle?

darryl
03-10-2005, 09:29 PM
Doing sort of the same thing myself right now. I'm building what's called a tadpole, which is a three wheeled thing with two wheels up front. This in not a car, but I think it's similar to what you have in mind. I have two bmx wheels for the front, and a single heavier wheel in the rear. I considered the same thing you are, and abandoned that because I couldn't see enough support for the front wheels that way. They do make a heavier axle for a larger hub, which would probably be ok like that, supported only at the inboard end. Check out those bmx type bikes that have the foot peg sticking out from both sides on the rear alxe. For what I'm building, I'm using forks and the same size axles you showed. I believe the larger size axle is about 5/8 inch diameter, and would be strong enough mounted that way, but you also have to consider real world forces. What if you hit a pothole, will something bend- I think it's likely unless you go with a setup that's already made to work this way, a stub axle. Checkout the tadpoles and deltas, both three wheeled vehicles, the delta being the one with two wheels at the rear end, and the tadpole with the two up front. There's a few informative web sites that show some mechanicals. Just look up tadpole, and go to what looks like bikes or recumbents. I don't have the links, but it's easy to find.

Yankee1
03-10-2005, 09:56 PM
Hi Arbo,
I don't think that will be strong enough,
the mechanical advantage that axle will have without support on the outboard side will be too great in that diameter.
When you consider shock that a bump can generate.

J Tiers
03-10-2005, 10:26 PM
Bicycle axles supported on one side only DO bend. I found this out a loooooonnnngggg time ago, no need to explain how at this time.

Smaller wheels, on "chugs" didn't do it, presumably due to the lower lever arm.

BTW I weighed a lot less then.

Sprocket
03-11-2005, 12:20 AM
Cannondale makes a one sided fork called the "Lefty". They may use a heavier axle.

www.cannondale.com/bikes/innovation/archive/carbonlefty.html (http://www.cannondale.com/bikes/innovation/archive/carbonlefty.html)

psomero
03-11-2005, 01:58 AM
<font face="Verdana, Arial" size="2">Originally posted by darryl:
Check out those bmx type bikes that have the foot peg sticking out from both sides on the rear alxe. For what I'm building, I'm using forks and the same size axles you showed. I believe the larger size axle is about 5/8 inch diameter, and would be strong enough mounted that way, but you also have to consider real world forces.</font>

whatcha wanna know about pegs?

the axles are 14mm diameter.

about the strength thing: people do grinds where they SLAM the peg onto ramps from many feet up in the air. the axle is the only thing holding the peg on (it's a tube with one end reduced to a 14mm pass through hole). there is a dropout stabilizing the base of the peg, but still. decent 14mm bmx axles are TOUGH. trust me.

darryl
03-11-2005, 04:52 AM
Well, I'd have to say that slamming the peg onto ramps from many feet up in the air is a real world force. I believe those 14 mm axles would do the job as a stub but the 8 mm ones won't. I do wonder about welding them to a steering knuckle though, just because of the heat treatment. Personally, I'd be inclined to thread them into a tapped hole in the steering knuckle assembly, keeping the play in the threads to a minimum, and using loctite and a jam nut. My 02

lunkenheimer
03-11-2005, 05:23 PM
What about some of the hubs and wheels used on wheelchairs? The axles are usually only attached on one end.
You'd have to modify the wheels of course, but they are made to take some degree of side loading.

You might get sporty and look into the wheels used on sporting wheelchairs (used for races, basketball, etc.) as a source of parts.

darryl
03-11-2005, 09:45 PM
I looked into the wheelchair axle idea, and quickly ran from the store before they robbed me. You can buy a new mountain bike for the price of one of those wheels.

Crazy Ed
03-18-2005, 03:49 AM
I have bought seversl times from:
http://bikepartsusa.com

Click on 'wheels' on the left column at bottom and you will find:

01-746806 Sun, 24x1.75, 105 Gauge Spokes, Trike, Rear, Wheel $036.72/ea

The front wheel has the same problem you have now!! Small axle (3/8). But the rears have either a 15 mm hole or a 5/8 inch hole, pick your bearings accordingly. Click on bearings. $3.99 ea, two needed for each wheel. An inner and outer.
01-6778727 Miami Sun, 15mm, Trike Bearings $003.99/ea

IF you decide to use this wheel setup, be sure to make a 'spacer' to go between the two inner races of the bearings so that the bearings can be squeezed together and NOT force the bearings to be side loaded inner to outer race by the tightening pressure.

Of course, your local bike shop MIGHT order these for you, but.. I doubt any cheaper!

The Miami sun uses three 1/4in holes, already drilled, in the side of those hubs that the axle has studs that slide into to apply power to one wheel. The opposite rear wheel freewheels on the axle to allow turning.

typing 'axle' into the 'search' function finds an axle for $20...5/8 size.

Not the prettiest hub/wheels, but strong and functional. I weigh 240lbs and have hauled 6 sacks of steer manure in the basket 4 miles! Plus many other 'heavy' loads, NO problems. And I corner by standing on the inside pedal..left many a skid mark on the surface.

Just fyi.

Disclaimer: I am just a customer of their a couple times...nothing else. I live in AZ and they are in Florida!

Gaerlan.com has a 20mm hub only, you would have to build it up with spokes and rim, but it takes disk brakes!! For $80

http://gaerlan.com/bikeparts/parts/hubs/hubs.html

Scroll down almost to the bottom of the page.

Again, just a customer. Located in San Francisco.

[This message has been edited by Crazy Ed (edited 03-18-2005).]

[This message has been edited by Crazy Ed (edited 03-18-2005).]

[This message has been edited by Crazy Ed (edited 03-18-2005).]

roasted7
03-18-2005, 10:00 AM
Hey, I used to make wheelchair hubs and quick release axles form fast easy wheel changes. Axles were 5/8 diameter 316 stainless with a 3/8 diameter hole drilled through. I have never heard of one failing.

Anzaniste
03-18-2005, 02:55 PM
I'm onto the same thing, its fun being a grandad isn't it.
My solution to the front axle spindle is to use the spindle out of a pedal. Only supported at one end a pedal will carry my 240lbs, that should be strong enough for a front axle spindle. They also have the advantage of having left and right hand threads which is just what 's required.

ZMAN
03-19-2005, 07:14 PM
Have you seen the Cannondale's Lefty??
http://i6.ebayimg.com/01/i/03/a5/54/1a_12_sb.JPG SZ