Red Bull Motorsports
Soapbox Race
Red Bull Racing’s ultimate billy cart and soapbox-building guide
The F1 team’s Chief Engineering Officer Rob Marshall tells us how to win at building a machine for Red Bull Billy Cart Race.
Red Bull Billy Cart Race is coming back to Australia in 2022!
Once again, you'll be able to see an amazing array of sublime homemade, engineless crafts, piloted by truly fearless competitors.
But how do you make a billy cart racer fast while ensuring that it’s sturdy enough to withstand a battering over a series of gnarly obstacles? Here's someone who might be able to help...
Rob Marshall is Chief Engineering Officer at Red Bull Racing, and has been an integral part of the team's huge successes in Formula One, including Max Verstappen's 2021 Drivers' Title.
Here are Rob's top five tips for engineering speed and reliability to create an unbeatable billy cart...
01
1. Use a solid base
"Start with something that is already a reasonably proven and robust device. You see so many [billy carts] with a bicycle or go-kart design as the basis, or with elements of those things, and those tend to have a good chance.
They need to be pretty robust, not carry too much weight and have slippery bearings
"You need strong wheels and strong axles, because it isn’t a smooth ride – there are bumps and jumps; you often see [carts] take off, and everything looks fast and under control, but when they land, the wheels are broken and splayed and then it’s game over. They need to be pretty robust, not carry too much weight and have slippery bearings."
Rob knows how to make a strong, fast racer
© Getty Images/Red Bull Content Pool
02
2. Get the basics right
"If something is built on a sensible chassis – something with a robust frame, four wheels and a means of steering it – you can stick anything on top of it. You can put a 10ft high Christmas cake on it or make it as aerodynamically efficient as you want. Anything that has two-by-four planks of wood and axles bolted on – one bump and it will fall apart.
You know the really elaborate designs aren’t going to make it to the bottom of the hill
"Some of the really elaborate ones, you know they aren’t going to make it to the bottom of the hill when there is just too much going on. Don’t get me wrong, some look really impressive; some are built from scratch and you think they’ll be slow and fall apart, but somehow they work.
"I remember one year seeing a VW camper van [the Hippy Split Camper Van from 2013 in London] and it was just a beautiful thing. It ended up in a bit of a mess, but it looked amazing!"
Rob loved the Hippy Split Camper Van from 2013
© Nathan Gallagher/Red Bull Content Pool
03
3. Keep the driver as low as you can
"From the point of view of going quickly, you need to get your bodyweight as the driver as low as possible. The designs that tend to go the quickest are when the driver is sat as low as possible and between the wheels, rather than up high, as they are prone to topple over.
The ideal [billy cart] racer would look like an old school racing car...
"If you had to say what the ideal [billy cart] racer looks like, you’d take an old school racing car – one before aerodynamics came along, when they were basically a teardrop shape with four exposed wheels. That would probably be a bit quick, and if everybody did that, it would be a bit boring. But as a basis, that’s a good way forward."
An old school race car – the ideal soapbox racer?
© Nathan Gallagher/Red Bull Content Pool
04
4. Pay attention to aerodynamics
It sounds stupid, but aerodynamics do play a part. If you have a lot of flat surfaces and things sticking up in the air, it will slow you down. There’s no such thing as no drag, and if you want to be the quickest, you have to have the least amount of drag. If you build the thing so you are nice and low, then you are going to minimise drag.
Strong wheels and strong axles are the key...
If only these guys had listened to Rob…
1 min
Red Bull Soapbox Race London 2015 best crashes
It wouldn't be Red Bull Soapbox Race without some hilariously embarrassing meetings of face/road.
05
5. Use bits from a go-kart!
"I would get a kid’s go-kart – not even a motor-powered one, just a pedal-powered one will do – use the front axle and steering mechanism and attach some strong wheels. When people start getting planks of wood and chopping things up, those sorts of crafts tend to fall apart pretty quickly. You see a lot where you have some old pram wheels and the spokes aren’t capable of taking the load. Strong wheels and strong axles are the key."
Strong wheels and strong axles stop THIS happening
© Ali Bharmal/Red Bull Content Pool
And my design? "It would have to be a Spitfire. You could take the wings off or pull them up, so it looks like an aircraft carrier-based one. I judged the Red Bull Soapbox Race one year, and one team had a [cart] designed in the form of a Sopwith Camel. It was magnificent!
"It wasn’t just the fact they had built a Sopwith Camel; they had a proper, old school, First World War tent and they were brewing tea; they had moustaches and flack jackets and all that, and for the whole show they were in character. They were absolutely amazing."
Red Bull Billy Cart Race returns to Australia this December, click here to enter!
