About the WRCCA Ruleset

Introduction

If you’re looking to compete in a local RC rock crawling club that uses the WRCCA ruleset, or a variant of it, you may have had a bit of a shock when you first opened the document. It’s lengthy alright! I’ve found that once you break it into a few parts, it isn’t so overwhelming.

The first section is all about how the comps are scored. We won’t cover those here, as I’ve found that these are best learned by turning up to a comp and experiencing the scoring yourself. It seems like a lot but really it’s mostly about scoring drivers as they work through the gates on a course, and the various ways you can gain or lose points in that attempt.

I do have a few videos where I’ve done a bit of a demonstration of this on-screen, while I drove through a course. If you’d like to see how scoring might apply at a comp, you might take a look at this video, where I overlaid the various demerits on-screen as I drove the various vehicles on a course.

For this article, we’re going to focus on outlining the rules that pertain to building a vehicle in one of any of the 7 classes the Australian clubs are largely using at time of this article. Those classes are Super, Pro, Sportsman, Mini, Performance-Scale, Scale-1 and Pricey’s Customs Tuff Truck. Let’s get to it!

I’ve decided to write this (and to make a video series) to help you get your head around the rules, one part at a time. This is intended to be an introduction to the rules rather than the final word. Once we’re done with this write-up, you’ll have a better idea of how to proceed with your build or builds from here.

Vehicle Requirements

First, let’s talk about what kind of vehicles are allowed in this competition. Only 4-wheeled vehicles are allowed, unless there’s a special exemption for a class. This means that the 4 wheels have to be the only source of propulsion for the vehicle.

When we measure the vehicles, we need to make sure that they’re sitting on a flat surface. This is the only way we can get accurate measurements of all the different parts of the vehicle. And just to be clear, we won’t be measuring the shocks or any fasteners that are holding the vehicle together.

One important measurement we’ll be taking is the wheelbase, which is the distance between the center of the front axle and the center of the rear axle. And to make sure the vehicles look like real-life vehicles, the roof of the vehicle needs to be raised at least one inch from the main chassis, and the sides of the frame need to be at least one inch tall.

We also want to make sure that the vehicles resemble real-life vehicles. So, there are some minimum measurements for width, length, and height that the vehicle or its bodiless measurements must meet. You can see those requirements in Illustration B in the rules document.

Now, if you need to lower the axles for some reason, that’s allowed. But, the winch line must be attached within half an inch of the center of the axle and only have one attachment point.

Finally, there’s no limit on the number of radio channels you can use on your vehicle, unless it’s specified in the class rules.

And just to make sure everyone’s on the same page, I’ll go over how we’ll be measuring the vehicles. The track width will be measured from the bottom of the outermost edge of the front and rear tires, and the wheelbase will be the distance between the axle shafts in a resting position. But, just to be clear, during suspension articulation, the wheelbase must not exceed the maximum allowed by the specific class.

And that’s it for the vehicle requirements! If you have any questions, make sure to check out the rules document (see top-right menu on this page) or reach out to us. Now, let’s get to the vehicle classes.

Super Class

The Super Class has some specific rules to follow when it comes to your vehicle. Firstly, your vehicle’s wheelbase must be between 16 and 18 inches. There’s no restriction on the steering configuration, so you’re free to choose whatever works best for your vehicle.

The wheels and rims must have a minimum diameter of 3.2 inches at the bead surface, and you’re allowed to modify the wheels as long as the tire bead surface remains at least 3.2 inches in diameter. You can also modify the tires, but only using pliable rubber.

Finally, the body or bodiless measurements of your vehicle must be at least 12 inches long, 3 inches wide, and 3 inches tall.

Pro/MOA Class

In the Pro class, also known as the “Pro/MOA” class, there are several specific requirements for the vehicles competing in this class. First and foremost, the wheelbase of the vehicle is limited to a maximum of 12.5 inches or 317.5 millimeters. Additionally, the track width of the vehicle is also limited to a maximum of 12.5 inches or 317.5 millimeters.

When it comes to the wheels and tires, the wheel or rim size is limited to 2.2 inches or 55.88 millimeters at the bead surface, and with a tire mounted, no exterior component of the wheel, including but not limited to the bead lock ring, shall exceed 2.55 inches or 64.77 millimeters. Tires may be modified using only pliable rubber, but they must not exceed a total uncompressed outer diameter of 6 inches or 152.4 millimeters.

Another important rule for the Pro class is that vehicles are limited to 2-wheel steering only. In terms of body measurements, the vehicle’s body or bodiless measurements must be greater than or equal to 8 inches or 203.2 millimeters overall length, 3 inches or 76.2 millimeters overall width, and 3 inches or 76.2 millimeters overall height. Finally, vehicles in the Pro class are limited to a maximum of two motors.

Mini

Welcome to the Mini class! This is where we really start to shrink things down. Both the wheelbase and track width are limited to 9 inches, which is about the size of a decent burrito.

Now let’s talk about wheels and tires, the wheel/rim is limited to 1.9 inches, but don’t worry, you can still modify it as long as the tire bead surface is no bigger than 1.9 inches. And as for tires, you can modify them too, but they have to be no bigger than 4.95 inches when they’re uncompressed.

Steering is limited to 2-wheels on the front axle only, and you can only use 2 channels on your radio. Your vehicle is also limited to 1 ESC and 1 servo, so no fancy tricks here. Remember, you’re limited to just 1 motor to power both of your axles.

Only two channels are allowed in Mini, and they can only be for steering and throttle control. You’ve got options for the body styling and it can be polycarbonate or a comp-style tube or CF frame. There are minimums for overall vehicle dimensions: you need to be at least 6.75 inches long, 2.5 inches wide, and 2.75 inches tall.

Lastly, your motor must be chassis-mounted, so you can’t attach it directly to the axle. That’s it for Mini!

Sportsman

Alright, let’s talk about the Sportsman class rules. This class is also known as ‘Sporty’ or ‘Shafty’. First off, the wheelbase of the vehicle is limited to a maximum of 12.5 inches or 317.5 millimeters. This means that the distance between the front and rear axles is limited to this measurement. Next, the track width of the vehicle, which is the distance between the left and right wheels, is also limited to 12.5 inches or 317.5 millimeters.

When it comes to wheels, the rim size is limited to 2.2 inches or 55.88 millimeters at the bead surface. But, modifications are allowed as long as the tire bead surface does not exceed 2.2 inches or 55.88 millimeters in diameter. Additionally, with a tire mounted, no exterior component of the wheel, including the bead lock ring, should exceed 2.55 inches or 64.77 millimeters. Tires may be modified using only pliable rubber, but the total uncompressed outer diameter must not exceed 6 inches or 152.4 millimeters.

Vehicles in this class are limited to 2-wheel steering only.

In terms of the body, vehicles must have one! It can be a cage-style integrated body with the chassis, or a lexan body that is removable. Bodiless vehicles are not allowed. The bodies must resemble a 1:1 vehicle with cab, door, and hood panels, and have measurements of at least 8 inches overall length, 3 inches overall width, and 3 inches overall height.

For controlling the vehicle, the use of 2 radio channels is limited – one for steering and one for throttle. Neither channel can be used to perform more than one function. If a radio system has more than 2 channels, only 2 channels can be used to control the vehicle.

And finally, vehicles in this class are limited to 1 ESC, 1 Motor, and 1 servo only, and the motor must be chassis mounted. The motor mount cannot be part of or directly coupled to an axle.

Performance Scale

The Performance Scale, also known as Class C2, is designed for vehicles that have been modified for trail-rated or competition-based performance. These vehicles may not necessarily be street legal.

To make sure your vehicle meets the requirements, here’s what you need to keep in mind when you build or set up a rig:

• Your vehicle should have a full body, from the grill to the B-pillar, with no cuts or modifications to the grill. However, you can trim the wheel arches and headlights for clearance.
• If your vehicle has a cab only configuration, it needs to have a frame, bar work, or tray. You’re allowed to remove the roof as long as a roll cage or half interior is fitted.
• The body, including any tray, cage, or bar work, should be at least 3 inches longer than the wheelbase.
• The body or cage work should be at least 4.5 inches from the A-pillar to the B-pillar of the cabin.
• The body should be at least 5 inches wide for the full length of the passenger cabin, which is defined as from the furthest point of the front windscreen to the furthest point of the rear window.
• You’re allowed to section or narrow the body from the A-pillar forward and the B-pillar backward, but it still has to meet the requirements for full body, width, and length.
• The inner side wall or shoulder of the front tires, measured at the axle center, should be covered by bodywork when viewed from above at rest. You can add flares to the body to obtain coverage.
• You need a front bumper that is at least 2.75 inches wide, centered on the front chassis rails, and should flow through a continuous line. Chassis-mounted bumpers need to project at least 3mm past the body, and body-molded front bumpers can’t deflect inwards.
• Clear or “swiss cheese” bodies are not allowed, and you should aim for realism.
• No electrics other than a steering servo are allowed to be mounted or fixed to axles or suspension links.
• Receivers are limited to 2 channels only.

Let’s talk about tires and wheels. Your vehicles must have wheels or rims no larger than 2.2 inches or 55.88mm at the bead surface. The tires must be no bigger than 4.8 inches in diameter or 122mm and no wider than 55mm from sidewall to sidewall. The tire size will be determined by what’s listed by the manufacturer. If the specs aren’t available, the tire will be measured on the vehicle as mounted on the wheel laid flat. You’re allowed to sip, groove, shave, or remove lugs from the tire, as long as it still meets the size rules. But cutting, narrowing, reducing, or increasing the size of the tire is not allowed. You can’t cut the tire carcass either. And, production pin tires are not allowed even if they meet the size rules. Lastly, weighted knuckles or knuckle weights must fit within the bead circumference and carbon fiber wheels or rims must have an offset or beadlock ring built in.

Now, let’s move on to drive train. Vehicles are limited to front wheel steering only and must be shaft driven only, powered by a single motor. No “Motor on Axle” of any kind is allowed. You must have one transmission or transfer case and at least two drive shafts. No separate throttle control of the drive shafts or axles is allowed and there’s no front or rear dig or axle disconnects.

Finally, let’s talk about the chassis. Your vehicles can have a C-Channel, tub, tube, rod, molded plastic, or plate chassis. Shock hoops must be no higher than 2.75 inches or 70mm above the lowest point of the skid. The upper link mounts on the chassis must be no more than 1.18 inches or 30mm higher than the lowest point of the skid. The chassis must cover all axle centerlines and can be two pieces that are screwed, bolted, or welded together. The wheelbase must fit the dimensions of the body being used. If a tray-back or truggy cage is being used, the wheelbase will be defined as double the distance from the front axle to the A-pillar and double the distance from the front axle to the B-pillar. The battery trays must be mounted to the chassis and the section of the chassis that counts as one continuous length must have the skid plate attached to it directly.

Pricey’s Customs Tuff Truck

Now we come to a new class, Pricey’s Customs Tuff Truck. This class is for full-tube style buggies and cars that are similar to what you see at Tuff Truck and Werock/Ultimate Rock Sports events. Before the event, each car will be checked to make sure it fits the class criteria.

Let’s go over what makes a car fit for this class. First, the chassis. It can be made from anything like plastic, titanium, steel, alloy, and more. Just as long as it’s tubular!

Next up, the tires. You can use 1.9 tires with a maximum size of 5.4 inches. This is the biggest size you can find at the store. And if you want to use 2.2 tires, they can be no bigger than 5.4 inches too. Just make sure they look like real tires.

Now, let’s talk about the axles. You can use any driveshaft style axles you want. Rear steer is allowed and even recommended. You can steer your car however you want, with a Chassis Mounted Servo or an Axle Mounted Servo. But, you can’t use MOA axles.

The drive train has some rules too. You can only use regular and commercially available transmissions. And, if you want, you can use front DIG. But, twin-motor and MOA-drive style transmissions aren’t allowed. You can have as much overdrive as you want in the axles and/or transmission.

Finally, the geometry. You can have any wheelbase you want, and any kind of suspension.

Scale-1

Lastly, we get to Scale-1, often referred to as Class 1 or C1, although that name is from a different ruleset. Here’s what makes a Scale-1 vehicle, essentially: it’s an off-road vehicle that looks a lot like a regular car you might see on the roads. The idea is to make the truck look as real as possible. An example of a Scale-1 vehicle given in the rules is the Camel Trophy Land Rover Defender, though pickup or ute style off-road 4x4s are arguably more commonly seen in comp settings.

Next, let’s talk about the bodies of these vehicles. They need to be a scale representation of a real car, from the front to the middle pillar. You’re not allowed to make big changes to the guards, just small cuts for clearance. Truggy and cab-only vehicles are not allowed, but flatbeds with full length rail chassis are okay. The bumpers need to be fitted to the front and rear and be the same width as the hood. You can remove the doors or roof, but you still need to have a windscreen and a full interior. The vehicle also needs to have two headlights and two taillights. The tires can’t stick out more than 50% of their width beyond the body. The rules do get specific on body lengths in regard to the total wheelbase and how much cab vs tray there is – best to see the rules document for the specifics.

The vehicles need to be built on a plate rail or C-channel ladder style chassis and that chassis must be 75mm longer than the wheelbase. Lower suspension links need to be straight, or in other words, you can’t use bent links. Wheels need to be aligned vertically within the body. Vehicles must be driven by a single motor, gearbox and transfer case, and can’t have a Motor On Axle setup. Steering is only allowed on the front wheels and the steering servo needs to be mounted on the chassis. Vehicles are limited to 1.9 inch wheels and 106.4mm maximum external diameter tires.

All electrics need to be hidden when viewed from the top, side, and through the windows.

Finally, let’s talk about the handicap points. Drivers be scored based on their course performance, per the standard competition rules. But then at the end, their vehicle’s additional scale handicap points will be added to the score – and if you’ve done a good job with your build as far as scale points are concerned, even if you DNF on a course, it’s not impossible to still come out even under a score of 0 if you made enough forward progress.

You should know that if a handicap item falls off during the course, the driver will need to put it back on before continuing. And that’s it for the Scale-1 class of the WRCCA ruleset.

Conclusion

Once you start to look more closely, I hope you’ll find that it isn’t so confusing after all. The rules are there to ensure all vehicles share the same basic limitations and capabilities. A common question once you start to understand and then begin your build is whether “x” is allowed, as it isn’t listed in the rules.

The general answer is that if what you want to do isn’t specifically disallowed by a particular rule, or isn’t disqualified by implication of other rules, then you’re good to go. A common example here might be whether portal axles or remotely activated locking diffs are allowed. None of the rules specifically prohibit this in Scale-1, so you’re good to go. However, while you’ll be able to run portals in P/Scale, you’ll find that only 2 channels are allowed to control your rig, which rules out remotely locking diffs in that class.

If in doubt, check the rules – they’re linked at the top of every page on our site here.

Video: you can find the video series that covers the above with some demonstration of how things are measured, etc., in this RC-TNT playlist.

We hope you’ve found this summary to be helpful. Happy building and enjoy your next comp! It’s a great part of the hobby!

-Catch you out there! -Craig, Melbourne Comp Crawlers