Billycart

[sports racer]

After seeing a few videos from the Australian Illegal Gravity Racer Federation I knew I had to build up a billycart to race down some of the mountain roads around my place.

This is what it will eventually look like.



So far all I’ve done is weld up the frame. It’s a mix of whatever metal I could find at the Braidwood tip, mostly discarded trampolines. When I’m seated my head clears the rollbar by a few cm so I should be able to use my motorcycle helmet when I run this thing.




It’s easier to see what it will eventually look like with the wheels resting against the frame. The wheels are 20” BMX and the frame is 2 metres long. Steering will be custom made incorporating Ackerman steering, zero camber and adjustable castor. Front brakes will be bicycle disks and rears will be bicycle caliper brakes until I can afford to fit disk brake hubs.




I still have to add some gusseting and lots of brackets for the steering, seat and wheels. All the welds will get ground back (they look like crap but are strong). After that it gets painted and then the bodywork goes on. Bunnings have 2.4 x 1.2 metre sheets of the same stuff Real Estate Agents use for their for sale signs. I’ll probably use that because it’s very lightweight and only $11 a sheet. Currently the frame is so light I can lift it with one hand (just). I want to keep it light so I have the option to add weight wherever it does the most good.

Hopefully it will be finished in time for the Yass billycart race in November. The low speeds reached on the Yass track shouldn’t disadvantage my non-aerodynamic cart but this one is really built to race down mountain passes. That’s why it gets a rollbar, side intrusion protection and a 5 point harness. There’s a long drop off some of the corners on the roads I’ll be running this. Just don’t tell my wife.

As always any tips would be appreciated or let me know if I’m doing anything I shouldn’t.

Here's a few of the ones they race overseas. All powered by nothing but gravity.





Cheers

Paul

[sports racer]

These are the guys who are serious (and just a little bit crazy).

[sports racer]

Update time

For the rear end I wanted a few positions so I could set the ride height.



Front end came from a ride-on lawn mower but the spindles were too short so I welded on an extension. They were also way too thin. I needed 20 mm and they were 16 mm so a slieve was welded on. It originally came from a lamp stand I found at the tip. Do you know how many bits of pipe I looked at before I found one with internal dia of 16 mm and external dia of 20 mm?

The advantage of using the lawn mower bits were built in positive castor and zero scrub geometry. This cart has to be able to race down mountain roads without stacking.



Here's the front hub ready for a rim

[Silver dub]

Sooo Cool.

That green hot rod is awesome.

[Goon]

This looks cool as hell man!

Last pictures didn't work though?

[sports racer]

Pictures redone so you should be able to see them now.

Here's what the cart looked like with some of the bodywork added.



I thought that's way too tall so I cut 70 mm out at the back and 180 mm at the front.

[sports racer]

For the front end I wanted some movement if I hit a bump so the steering assembly was mounted on 1 bolt so it can pivot. It has a few holes to choose from so I can set the ride height for different conditions.



Rack-and-pinion steering came off a mates burnt out ride-on lawn mower which I think is pretty cool for a billycart.

Can anyone tell me what's the major design fault with this setup?

[sports racer]

For those who eagerly await my yearly update on one of the all-time greatest events on the planet here is my report on the 2016 Braidwood Billycart Derby.

This is the first cart I built for the 2013 event. It ran well, was super comfortable but the aerodynamics held it back. I’m pretty sure it could have been a world beater if only I’d added some cup holders. I kept spilling my drink while racing and couldn’t steer straight.

My wife and kids also disowned me when I showed them what I was secretly building in the shed. I thought they’d be pleased at my recycling efforts but words like “embarrassing” and “turkey” were thrown around. My wife also had a few other choice words but the forum filter won’t let me print them.





For many months afterwards I searched the Braidwood tip for a sporty version of the Jason Recliner but no-one was throwing out their leather racing model so I built the hotrod instead. The main criteria for this build was it couldn’t be anything that embarrassed my wife or kids.

First raced in 2014 it got the people’s choice award for best looking billycart and in 2015 it managed to win a few heats which was good enough to get some prize money for the best placed Braidwood local in the Open class.



For 2016 I knew the local competition was keen to knock me off my pedestal so a new cart was built. Months went into the planning and construction of a much more aerodynamic cart and this time money was no object. After all, this is the world’s premier billycart event.

However, after spending $30 it was realised there would have to be a financial cap to this project otherwise the build would eat into my morning coffee (with 7 sugars) money.

To keep down costs many weekend afternoons were spent searching the Braidwood tip for the right wheels and bicycle frames to use, together with wood sourced from various backyards.

The 2016 build started with this.



2 months later and the day before the big race.



There were design limitations so that my 13 year old son could also use it to compete in his age class. As you can see below he fit with room to spare but his chubby dad was much tighter.



It was painted it in race winning colours (everyone knows red goes faster) but I could only find half a can of red.

Here Benny lines up against the cart that won it’s age group at Yass and Port Kembla, the 2 biggest billycart races in Australia.



Benny dead-heated against the blue cart in their first race and in the re-run Benny wobbled a few times going down the hill which lost him some speed. He lost by 10cm which isn’t too shabby considering the blue cart has never been beaten.

Benny had problems with the brakes and hit a few haybales trying to stop in one of his races. In another race he went through the haybales, across a busy road and ended up stopping in the carpark. The organisers banned the cart from any further racing and I had to argue with them to get the cart back into the race so I could compete in the Open class.



Here’s some of the interesting carts from this year’s competition.















How did our cart go in the hotly contested Open class?

Against the other 23 carts in the open class I got this.



Got to be pleased with that considering my $30 cart lost to this one which is rumoured to have taken 800 hours to build at a cost of $9000. I was lucky that this cart eliminated some of the other really quick carts in the heats leading up to the final race.







The guy owns a furniture making company and I think his staff were employed to help make it. He also lost 15kg so he could fit in it. That’s dedication and he rightly deserved to win.

Next year I’ll see about fitting high pressure tyres (expensive) and ceramic bearings (mega expensive).

If I get a small coffee each day @ $3.50 instead of a medium @ $4.20 that’s a saving of 70c per day. That’s $3.50 a week x 52 = $182. Almost enough to buy 2 bearings for 1 wheel so just 6 to go and then the tyres.

Wonder if I can get the kids to agree to less pocket money for the next few years and my wife to cutting back on the shoes and clothes?

I think I’ll probably be getting out the cup and sign and standing on street corners. If you see me please throw a coin.

Cheers

Paul

[nick_mk1]

Drove past! Looked like fun!


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[sports racer]

It was a blast.

You didn't happen to see a red/white/black cart race across the road being chased by half the officials with the other half worried about their limited liability insurance?