Soapbox racer designs... Any suggestions?

So while I have a fair bit 'o time on my hands these days, I'm building up a soapbox racer. Why, you ask? Why not.

Here's what I've got:

4 X 8" rotor, with full hydraulic calipers

4 X Marzocchi 40mm coil over shocks, and 2 Fox 5" downhill shocks

2 X 20" rims w/ slicks for a BMX bike

2 X 24" rims w/ slicks for a BMX bike

4 X 20mm thru-axle, disk ready, front hubs for a downhill bike.

And lots of "these look like they could be useful" parts too.

I'm kinda partial to a belly tank style set up, with 4 wheel independent suspension, or F & R live axles with a radius arm set up and coil overs.

Haven't gotten much past that, so I'm open to ideas.

Cheers,
Dan

 

Speaking of soapbox derby cars, what happened to the illegal guys? They should be due with another video. I like the one with the shrinkrap body!!

 

Are there any rules? There must be a weight limit? Make the car as heavy as possible, balance the weight evenly on the 4 wheels. The better the wheels & bearings the faster the car will go. Getting all 4 wheels perfectly aligned is also important. This is the best I can remember as my soap box derby days have been done for 30 years.

 

I don't think this is the forum for soap box cars with dubs and coilovers.

 

I read once that hey have kits that have specific parts you have to use, mostly involving the wheels, tires and brakes.

 

I think we're talkin' here of the illegal soap box racers, like those found at http://www.flickr.com/photos/telstar/sets/1258403/ . Definitely not "traditional" rodding, but definitely "traditional" kids-who went on to become hotrodders" and later sought to regain their inner-J.D.

 

Sorry about forgetting the "O/T" on the original post. This is kind of an out of work, geeking in the garage, building something cool for my son, etc, etc...

Yeah, this is along the lines of the "illegal" derby racing, but I am trying to maintain dimensions within the "gravity powered" guidelines - max: W 4' x L 10' x 175 lbs. Other than that, anything goes.

I figured it would be a good way to get my son involved in wrenching and rodding too. I thought a lakester or belly-tanker would make for a nice crossover between rodding and soapbox, and I figured I'd toss the idea out here and see what came back.

 

I've got a suggestion: Forget the gravity shit, you need H.P. and it sounds like you've got the fixins for one of these. http://www.stevproj.com/Carz/CycleKart.html

 

Oh! I DO want one of these.

 

Damn you Rootie! They just had to run on smal displacement motorcycle motors!! And I just happen to have a bunch of motors down in the garage.

Oh, and my housemate is a machinist.

This is gonna be a deranged little monster!

 

And you're building this for who?

Roger

 

I started building one of these for my kid, used an old (50's) aux. fuel tank as a body, cut it so it had a flat bottom 3" clearance and used an old metal 'flying saucer' type toboggan as the back just so it was rounded off nicely.
The rear axle set-up was from an old golf bag caddy, really cool, made out of cast aluminum with adjustable camber.
Front axle was a piece of 1" square tubing, streamlined with oak and covered with 'glass.
Wheels were really trick, they were made with 11 1/2" pullies and I used big 'O' rings as tires. These I stuck to the pullies with urethane.
This thing was cool looking, so cool that when I showed up at our local derby with it (which was illegal, by the way) that the organizers wouldn't let my kid run it. Made me happy, thats for sure.
Anyway, the thing has since been cannabilized for other various 'father/son' projects and I have been recently thinking of bringing it back as a wall decoration in the rec room.
The sickness continues.

 

As one of the "illegal" guys, and one that ran larger-diameter spoked wheels on my first "car", I can tell you that you'll probably want a few degrees of camber, especially on the rear wheels. This will not only put more of the rubber of a bicycle tire on the road, but will minimize lateral flex of the wheel in the corners.

If you think that your "son" might be competing in any of the illegal soapbox races, you might also consider some wheel discs to cover up the spokes, which are vulnerable to protruding axles from other racers when rubbing in traffic. It seems that there are basically two thoughts on illegal soapbox cars - low, long and narrow "laydown" cars for high speeds, and low short and wide "upright" cars for twistier courses.

Top cars right now seem to be leaning toward full suspension and multiple braking methods - disc, band, drum or scrub brakes for hard braking, and a drag brake to regulate speed without overheating the main braking system.

There you go - I say do the belly tanker, and 4-wheel independent suspension would allow for more geometry changes, but solid axles will be much simpler, tougher and easier to repair after a crash. BTW: don't run a live axle in the rear - having the rear wheels locked together is the best way to a slow car in gravity racing.

 

Those cycle cars are totally cool.

I went from being soapbox derby obsessed as a 10 to 12 year old to being mini-bike/go-kart obsessed as a 13 year old to be being snowmobile obsessed as a 14 year old to being GTO obsessed from 15 to 18 to being obsessed with all things related to cars now.

 

Damn, I have been looking for those ever since I saw an article in Popular Mechanics a few years back...

I wish some one actually had plans of them...

or..

EMT conduit space frame...

Aluminum body...

 

Wow Rootie, You have turned me on to a site of great interest. What cool rides those must be to blast around in. Thanks for the post.

 

Not a soapbox, electric powered and a small fortune but pretty cool.

http://cgi.ebay.com/ebaymotors/ws/e...ADME:B:SS:US:1123&viewitem=&item=120187837064

 

That thing looks scary and dangerous. I gotta have one. hehehe