R/C is a hobby, and a fantastic and fun one at that, but there is also a competitive side—most often in the form of racing. R/C racing has been around just about as long as there have been R/C cars. Racing first took off in parking lots on temporary tracks. As a whole, the hobby has come a long way from the days of parking lot racing. Today there are all sorts of type of competitions. The rock racing segment is a prime example of the awesome variety available. You can learn more about rock racing here. Getting started in racing or even just a segment new to you can be a bit daunting. One of the biggest questions is what class does my rig belong in and what are the rules. Using U4RC as the guideline, here is a breakdown of what class you can expect to compete in at a rock racing event with your Axial Racing vehicle.
If you have an Axial SCX10 with stock or stock-sized 1.9 tires, you can run and be competitive in the 1.9 Trail Limited or 1.9 Trail Pro classes. The 1.9 Trail Limited class is suggested because it is limited to solid axles only and the competition will not be heavily modified.
The 1.9 Trail Limited class only allows for 2S LiPo and motors are limited to 21-turn brushed motors or 18.5 2700 Kv brushless motors. The SCX10 RTR models include Axial’s 27T motor is within the legal limit for 1.9 Trail Limited. While the 27-turn motor will be slower than other motors allowed, your RTR SCX10 won’t require a motor change to compete.
Motor selection can be a little tricky if you don’t know how the motor nomenclature works. When a motor limit is set at 21-turn, such as in the U4RC 1.9 Trail Limited class, the rule is indicating that 21-turn and higher motors can be used. The fewer turns a motor has the faster it will be compared to a similar motor with motor more turns. If the motor limit rule indicates a brushless Kv rating such as 2700 Kv, the legal motors are 2700 Kv or lower. This is because the higher the Kv rating, the faster the motor.
The 1.9 Trail Pro class removes the battery and motor limits, but is still limited to solid axles. This class will feature more heavily modified vehicles.
The Vanguard 2900KV brushless motor is legal for the 1.9 Trail Pro class and is an excellent motor for this class.
If you have a stock Yeti, the Yeti Limited class is the perfect class. The rules do allow you to upgrade the servo and servo horn, but the rest should be stock.
The next step up is the Yeti/EXO Pro class. There are no motor and battery limits. EXO Terra Buggies will need to be fitted with 2.2 tires to be competitive.
Heavily modified Yetis and EXO Terra Buggies are ideal for the Trophy 2.2 class. Metal cages are required, so this class is for more advanced racers.
Wraith and Ridgecrest
The 2.2 Competitor Limited class is limited to solid axles only, so this class is ideal for the Wraith and Ridgecrest. The U4RC rules even state, “This Class is designed for RTR and kits with Axial only parts.”
The 2.2 Competitor Limited class does restrict motors to 3150 Kv or less, but 550-sized motors are allowed. This means the Axial Racing Vanguard 3150KV is an ideal choice. This motor is loaded with torque and delivers more than enough speed.
The 2.2 Competitor Pro is also an option, but this class will be faster, so it is recommended that a Wraith and Ridgecrest receive some attention before entering this class. This class is ideal for a modified Wraith.
Even though the Yeti XL RTR can handle 6S, the Yeti XL class is limited to 4S to keep speeds reasonable.
U4RC is understanding that many people may be building rigs without a real understanding of their specific rules, so they will allow anyone to compete the first time they show. They will review the rules and your vehicle and explain what needs to be done to comply with the rules. Violations will not be an issue for the first race day, but will be expected to be resolved for the second race.