soapbox rules

Cartie Tech' Spec' Summary

The various events across the UK all have subtly different rules covering cartie dimensions, weights, etc. As an aid to race teams and event organisers, the SCA has published an overview of the more common rule sets and has derived a set of universal dimensions that would comply with all the rules currently in use (Universal Cartie) and a set of measurements that would include carties built for every event (Universal Event).

This makes it easier for teams and organisers to make informed decisions when building their carties or drafting/reviewing their construction rules.

At the moment, the derived specifications are;

Dimension Universal Event Universal Cartie
Max Weight (dry) Kg 100 80
Max Length mm 3000 2000
Max Width mm 1500 1118
Max Track mm   1118
Max Wheelbase mm   2000
Min Track mm 700 700
Min Eye Line mm   700
Min Ground Clearance mm   150
Brake Force KgF 40 50
Roll Bars Optional 2 roll bars & forward protection
Harness Optional Required
Min Wheels 3 4

Click here for the full source data. If you have any corrections or know of any other rules that should be included, please let us know.

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Useful Downloads - Rules, Specifications, Standards, Guidelines, etc

Creative Commons LicenseUnless otherwise noted, all documents on this page are published under the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 UK: Scotland License. This means you are both free and welcome to copy, distribute and make derivative works provided you;

1) give credit to the original document

2) do not use the work for commercial purposes

3) distribute any derived works under the same conditions.


  • SCA CartieSim - Comprehensive soapbox cartie speed estimation software for use by race organisers and competitors.

SCA Technical Specifications

SCA Rules

FISD Rules

FISD is the governing body for gravity racing in continental europe. Their rule books have been translated into english for information.

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Soapbox Competition Rules

The Winners Celebrate in the traditional styleCompetition rules control how the event is actually run and how you decide who the winners are. It is usual to have several prizes, with some being awarded for the fastest time and others for more subjective achievements such as "Best turned out", "Spirit of the event", etc.

Prizes might include;

  • Fastest time of the day
  • Fastest aggregate time
  • Fastest lady
  • Fastest Junior
  • Best turned out
  • BEst engineered
  • Best dressed team
  • Champagne moment
  • Spirit of the event

For liability reasons it is probably best to avoid having prizes for "Best crash", etc, since it would be difficult to argue that you are taking safety seriously while at the same time appearing to encourage people to crash.

For safety reasons, and also for reasons of space and the width of the track, soapbox cartie races often take the form of time trials, where each cartie has one or more timed runs down the course. However, if you have the room then head to head racing is undeniably more exciting.

Competition rules also determine what the age limits are, what tactics are allowed and what would be considered "cheating" - e.g. push starts, ballast, etc.

Example Rules

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Soapbox Race Rules & Regulations

The rules you adopt will go a long way to setting the tone of your event and the type of carties that enter, so before you consider he rules you want to use it's worth spending time thinking about what you are trying to achieve with your event. If you want a fun event that has maximum community involvement, you will probably prefer to have minimal restrictions on the design of the carties and should focus on basic minimal safety requirements as appropriate for the speeds you expect on the day and the nature of the course rahter than getting bogged down with the technicalities of dimensions, roll bars, etc. However, if your race is aimed at serious gravity racers then more stringent standards would be required. 

Standards There are two distinct areas to consider - competition rules and construction rules. Fortunately, there are a lot of rules about already, so you can pick and choose the best ideas to get a set that is right for you. Although there are several sets of rules available that purport to be a "national standard" for cartie construction, there are in fact no accepted standard rules. The variety of different event types make it very difficult to draft a "one size fits all" set of rules since what is appropriate for a 60mph race down a mountain would be ridiculously over the top for a 25mph trundle through a village.

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