SC Rally Proof-of-Concept

Rally cars are amazing. If you boil it down, they’re basically suped up cars you would see on the road. And they can jump!

There’s a small but loyal group of rally R/C enthusiasts that have seen a number of RC rally cars come and go over the years. For me it began with the HPI RS4 Rally, originally released in 1998. It was basically a 1/10th scale touring car with longer shocks and more suspension droop for a higher ride height. It also had a raised bumper for clearing bumps. Team Associated followed suit by offering a conversion kit to make a TC3 Rally. For the next 20 years various manufacturers have taken a stab at the rally game, some lasting longer than others.

RC Rallying Styles

RC Rallying overseas is done on scale courses where the driver follows the vehicle through the course which can be incredibly complex and/or long. It is very similar to RC rock crawling but at a much faster pace.

The SoCal RC Rally Runners stateside do a similar time-trial like setup, but on a smaller course where there’s (ironically?) less running. Lots of scale details have been added including bridges and small jumps.

But I’m OK with giving up a little bit of the scale detail. Why not run them at one of the many off-road tracks our country has to offer? We’re here to jump right? Sure the jumps will be comparatively HUGE, but if the cars can handle it, why not?

Also, as much I love WRC and the time-trial game, nothing beats racing RC cars door-to-door with your friends. I’m thinking something like what Ultra4RC racing is to crawlers… traditional main racing, just with rally cars. By racing at traditional off-road tracks, we’re going to need to go big with these cars.

Short Course Rally

Traxxas has been selling the venerable Slash for over 10 years now without many changes. What that means is there are a bunch of 2wd Slashes out there that are sitting on shelves, collecting dust. SC (Short Course) Rally would be a new lease on life.

Sure Traxxas already makes an out-of-the-box rally car based on the Slash 4×4 – but I want the sheer numbers of the 2wd Slashes out there to be able to participate as well. So keep driving your Traxxas Rally if you’ve got one, and if you’ve got a 2wd Slash or other short course truck collecting dust, consider this easy conversion. To keep costs controlled, I put together an example 2wd spec class list:

Spec SC Rally2

Truck

• Stock 2wd Slash (brushed motor, high center of gravity chassis)

Body

• Any fully-fendered car body (no truck/buggy bodies) – most 1/8 scale will fit. Here are some examples:
  • HobbyKing BSR Racing 1/8 Rally Pre-Painted Body
  • Deltaplastik
  • Parma
  • Traxxas 7411(X) 7412(X) 7416
  • Pro-Line/Protoform PRFX
  • Team Associated 7180 7181 7182
  • Baja Bug (Pro-Line) and BAJR (J-Concepts) fans – these are not full fendered. You should instead look at the Deltaplastik New and Classic Beetles.
• Pro-Line extended body mounts

Foam Bumper

• RPM wide Rustler bumper + Traxxas Rally Bumper Foam OR
• Integy Foam Bumper (for bodies with a longer front overhang)

Wheels & Tires

• RPM offset-compensating front A-arms – these could be considered optional, they just add +3mm of offset to the front so the wheel offset matches the body & rear tires.
• Traxxas 7471 Rally Tires (widely available, pre-mounted as 7473) – the reviews on loamy dirt were only fair but it would probably do well with traction compound like Spec Slash tires do
• Traxxas 7471R S1 Compound Rally Tires (less common, but better grip)

SC Rally4 & Beyond

If main style off-road rally racing catches on, there would obviously need to be a class for 4WD rally cars too. I imagine the class rules for this would accommodate all of the short-course based rally cars from various manufacturers. Some simple dimensions might be:

• Wheelbase 300-335mm
• Width 260-300mm
• 2S Battery
• Possibly a spec brushless motor? Maybe 4WD is destined to be a modified class.
• Some minimum weight standard

The real equalizer should be tires. Settling on pre-mounts such as the Traxxas 7471 or 7471R would be a good place to start. It would avoid racers messing around with the tire foams and wheels, trying to find an advantage. Other racing classes such as USGT and Vintage Trans-Am have seen great popularity by having spec tires and simple rules which encouraging close racing.

Testing

Rather than just dream about all of this, I put together a test SC Rally2 platform to see how it would perform. Tune in to the next article to see the results.