Design Guide

Our design guide has been put together to help you design everything from the most basic trolley up to a real speedster so you get out there and play with gravity.

Trolleys can be as simple as the old soapbox with 4 pram wheels (but please no rope steering) or a purpose-designed, 3 wheeler recumbent with an aerodynamic carbon fiber body!

If you are designing and building your trolley to participate in the Collingwood Street Trolley Derby, then you need to ensure that your trolley design complies with the Rules for Race Day.  The same Rules apply to any Funday races organize by the Nelson Trolley Club Inc. You can check out the Rules here.

For the FORMULA ONE DESIGN PAGE click here

Fundamentals
If speed is your goal, the action of your wheels and their rolling resistance is the most important aspect to consider.

Once you hit 40km/h, aerodynamics also impacts on your maximum possible speed.
Of course, speed is useless if you haven't got control, so pay careful attention to your steering, brakes and structural rigidity.

Keep your construction light!! Contrary to popular belief, weight is an enemy to every trolley.

Shaping techniques for the body of your trolley are almost infinite, ranging from cardboard and sticky tape to carbon fibre.  Whatever you use can make the most basic trolley look like a speed demon.

Wheels Your choice of wheels determines your rolling resistance. This is the amount of resistance your wheels have to the unavoidable pull of gravity that is trying to make your trolley career down the hill. The perfect trolley wheel is a compromise between weight, strength, contact area, braking performance, rolling efficiency and cost.

The lighter a wheel is the more acceleration it will have but a wheel must also be strong enough to withstand the forces of steering and braking.

The smaller the area of contact the wheel has with the road the less drag the road exerts on the wheel. This is great for acceleration but dire for braking - you see, it is all compromise.

Wheel bearings play a critical part in the speed of a trolley. Make sure your bearings are clean and use light oil.

Old wheelchair wheels are ideal as they have very strong axles and bearings. They can be attached directly to the side of the trolley. These can sometimes be found at the Nelson Refuse and Recycle Centre or also check out auction sites on the internet to see what is available. Old 10-speed bike wheels make great, cheap trolley wheels providing they are pumped up hard. However this type of wheel must be supported on both sides of the axle. Old motor mower wheels are fine but don't usually have bearings.

Pneumatic (air-filled) and solid trolley wheels with bearings can be bought for about $40 a pair from Opel Industrial or Mitre 10 Mega (both near the airport).

Brakes
"Brakes are probably the most technically challenging aspect of building a trolley."

Sam Laidlaw: designer of five Monarch of the Hill-winning trolleys

There are two common braking systems:

Deadman Braking  - this is where the brakes are held in the 'brakes on' position by a spring, bungee or bike inner tube.  To race, the driver pushes the brake lever and the wheels are released.  This is a great system for young drivers as the brakes only stay off while the driver is in control ~ the instant they freak out and move their feet, the trolley slows down.  See the system used by the Bed Buggy.

Active Braking  - Cars & bikes use an active braking system.

There are many ways to create rudimentary versions, for example:
• A large piece of car tyre rubber on a lever activated by the drivers foot;
• A hinged lever carrying the foot pressure via a rod to the back wheels.

For design ideas take a look at Brian Fangio Smith's suggestions.

If you use 10-speed or wheelchair wheels, it will be possible to have brakes on all wheels.

If you have a fixed rear axle you can incorporate a bike disc brake.

Shaping
There are essentially two types of vehicle construction:

1. Chassis and Body
2. Monocoque

A chassis and body structure has all strength in the chassis and the skin or body is cosmetic.

In a monocoque design the chassis and body elements are combined to create a more rigid and lighter vehicle.  Airplanes are an example of extremely efficient monocoque design

Both systems work well for trolley building as long as the weight and type of material is used not only to maximize performance but also to ensure the safety of the occupant, other drivers and spectators.

For a monocoque design, 3mm - 5mm plywood makes a great overall skin structure, which can then be filled out with polystyrene, cardboard and brown paper.

A design that uses chassis and body construction can really take advantage of lightweight skinning materials.

With the rigid structure taking the weight of the driver and the stresses of the braking and steering systems you can use polystyrene, cardboard, sticky tape, PVA glue and paint to create an elaborate and aerodynamic skin.

Make sure you provide clear lifting points for loading on and off the trucks!!

Ensure any sharp or solid protrusions inside or out are well padded for yours and others safety.

For stability and reduced air drag, position as much of your weight below the axle as possible.

As all trolleys must be loaded on and off trucks at least 6 times during the day keeping trolleys small and light makes it easier to get your trolley back to the top of hill.

And remember, a light trolley is a fast trolley!

Good Luck!



(This information hs been collated by Andy Williams)