How to attach bicycle wheel to a long axle?

April 30, 2008 7:43 AM

How to I attach a bicycle (front) wheel to a long axle for a (soap) box car?

I'd like to help my son build a non-league (not following any rules) homemade box car, and I'd like to use scrap bicycle wheels and tires. But I'm not sure how to attach the wheel to a longer axle that I can mount to the car. Also, where to get such an axle would be helpful.

posted by tippiedog to Sports, Hobbies, & Recreation (5 answers total)

You don't need one long axle, as such, which I am reading into your question as you thinking you need. You need a long support, and then mount the normal bicycle wheel at each end of it. There is a bar through a bicycle wheel that is threaded at each and and is clamped into the forks with a nut on each end (assuming no-quick release axles). Just mount a threaded support at each end of your 'axle' (which used to be wood in the old days) and clamp the wheel on the other side of that.

So it goes:

Nut, washer, wheel, washer, threaded block (of some sort), wood, pivot on centreline (repeat other side).

You could possible get a longer axle and make the 'threaded block' just a thick piece of plate steel and clamp it in the normal fashion as it if was a one sided fork. You'd have to use washers to space the wheel off though, I imagine.

This gives the classic, two pieces of string attached to a plank of wood that pivots in the middle, style of steering. If you want to get more complicated, let us know. It all depends on how much work time and skill you can put in...
posted by Brockles at 8:04 AM on April 30, 2008

Response by poster: Thanks, Brockles. I guess this part is my real question: Just mount a threaded support at each end of your 'axle'. How would I do that?
posted by tippiedog at 8:27 AM on April 30, 2008

if you get a threaded rod with a thread identical to that of the original axle, you can thread the cone and locknuts onto it, put the ball bearing in the cup on the hub, slide the wheel on, and put on the other bearings and cone on. tighten the cones until the play in the wheel is just about to disappear, and tighten the locknuts.

i've seen it done, but i'm a little wary of this system. a high-diameter wheel can exert a lot of leverage on the rod during side loads which may bend it.
posted by klanawa at 8:35 AM on April 30, 2008

Being as you seem to be without much in the way of resources (reading between the lines) I'd suggest going to your local fabricator and finding some strong steel angle - 1/8" thick, possibly 2 to 4" per side. If you explain what it is for (especially if you speak to the guys in the shop, they may give it to you for nothing. You will need two bits for each axle, each about 3 - 4 " long. Even if they make you pay for it, it'll be way less than $10.

You then need to drill a hole in the plate the same size as the one in the original forks (somewhere in the middle of one side) and just put the axle through there as if it were the original forks, just on one side. Bolt it up as normal, with washers as required between the plate and the cone assembly to ensure just enough clearance between the plate and teh wheel. You will then have a piece of plate sticking out of the side of your wheel that you can bolt onto a plank of wood/metal support that you attach to your cart. If you use wood, I'd suggest a think plate on the other side to the angle bracket and bolt it through, rather than try and screw the plate directly to the wood.

Repeat the other side. Use as much of the length of the lower side of the angle plate (like a triangle pattern of three bolts spaced as much as you can) to give maximum support.

If you want to get fancy, weld a nut onto the plate for the axle. For extra safety, the longer the axle, and the longer the support the threaded rod goes through, the less chance it will bend.

If you want to get more fancy, weld a side gusset/support to the angle that goes inwards from the wheel to support the side loads. Use a smaller wheel for the steering axle, also, to reduce this effect.
posted by Brockles at 9:08 AM on April 30, 2008

Response by poster: Brockles and klanawa, thanks. Your inference, Brockles, that I'm 'without much in the way of resources' is close. Actually, I just don't want this to become a big project. I want this to be a fun father-son activity, not an engineering project.

Based on what you two have written, I don't think this is a route I want to go down. I guess I'll look at lawnmower type wheels or something similar.
posted by tippiedog at 2:32 PM on April 30, 2008