I'm making a cart for the Woodhill Derby in July.

I'm hoping my sons will run it in the Under 9's and I'll run it in the Opens. I'm going for the classic open wheeler with a little more flair.

Spent a week of my lunch breaks on it so far and have the body almost done. Going to run 12" bike wheels and and bike brakes on the rear.

 

Edited April 14, 201412 yr by GJM85

So much fun to be had for bugger all money.

I've built a couple of billy carts for local events in the past two years, I would recommend 20" bmx rims for a better top speed over the 12's.

These were my efforts

 

Hope you and your boys have a blast

Unfortunately for every class with the exception of the Opens and King of the Hill the max wheel size is 310mm.

You've made a couple of gnarly carts there mate.

Farrrrrrrrk. My friends and I used to do this when we were teenagers. There was a small derby in a town called Bangalow and we'd make a cart every year. The first year the cart was wooden and had wheelie bin wheels, the second year it had 12" bike wheels and from the third year onwards we'd built a fully welded tube framed cart with Campagnolo 700c racing wheels and started referring to it as a "gravity racer". Shit got out of hand, but holly ʞ©$ɟ we aced that derby every year after that.

 

From the research I've done aerodynamics, weight and wheels are what make a cart. Some of the videos on the tube are far out there.

I've designed this cart around a 12in wheel with a 980 wheel base. 20in wheels would raise its centre of gravity to much and turn it into a rollover machine.

My brake plans.

 

There's the pedal brake.

 

Now it's under coated.

Not gonna lie. Really wanna build one for myself and bomb the hill from Maleny to Landsborough,

OK here are some pics of the death trap I built for my boys.

2 x 20" bmx donor bikes and some bits of timber.

This thing was way fast and dangerous as hell. Parenting at it's best.

Simple linked pivot steering and 1 brake which could not stop the thing.

Great memories.

Wow!

 

Looks cool! You going to do a 4A conversion?

Edited April 14, 201412 yr by rian

Is that the best & easiest engine conversion under 100$?

Being a 12th year apprentice I'm on a tight budget!

Took this thing for its maiden voyage yesterday. It's pretty fast. At first estimates I'm guessing around 25-30km/h on a 100m low to mid gradient hill. It weighs 23kg.

The steering is super sensitive. Tyre pressure set around 45psi. At the moment the front axle is routed in behind the steering king pin. I'm going to spin the whole around axle around so it's forward of the king pin and hopefully it's a little more controllable.

The brake works well with dual rear callipers. I totally forgot what driving one of the things at speed was like. Fast & Scary.

 

Edited April 17, 201412 yr by GJM85