Nobody likes making mistakes. If you’re participating in scale comps, mistakes will, of course, keep you from succeeding. Now, the old saying is it’s smart to learn from your mistakes. Well, I think that’s true, but I think it’s brilliant to learn from other people’s mistakes, so below are the top five mistakes people are making with their scale crawlers.
TOO MUCH ARTICULATION
This might be the most common setup mistake crawlers make (or maybe I just think it is because people love to show it off), and it has been an oft-made mistake as long as RC crawling has existed. It’s pretty obvious that articulation or suspension flex allows you to travel over rough terrain without the tires losing contact with the ground. To many people, it also simply looks cool. Flex is good, so more flex must be better, right? You may have guessed that the answer is actually no. Too much articulation allows a vehicle to get all twisted and bound up in difficult situations. Read the section on soft suspensions to see what happens and why. Most–but not all–setups that deliver tremendous flex also deliver excessive axle steer. Axle steer is when the axle (front or rear) moves in a front to back arc as it articulates (the truck crabwalks). The end result is unpredictable handling, which is far worse of a problem than having to hang one tire over, say, a crevasse type situation.
SUSPENSION TOO SOFT
This goes hand and hand with too much articulation, but must be handled separately. Why is too soft not too good? Think of all that torque your motor makes like it’s water flowing downhill–it takes the path of least resistant. So, if a tire is bound up, it will transfer that twisting power to the soft suspension. This usually happens when the rear tires are up against a ledge. Instead of putting power t the ground, the tires lock in place and the suspension starts twisting and squashing down. In general, you can get away with a softer front suspension. In fact, many experienced tuners setup the rear suspension a little firmer than the front. Axial offers different rate srpings for its scale shocks, so there is no reason to be stuck with the stock rate. The optional springs are great for tuning, of course, but you may also need to go to a stiffer rate to account for a heavier than stock vehicle after you accessorize your RC truck.
You can get a lot of bad advice online. That might seem like kind of an odd thing to say on an online media outlet, but it’s so very true. Some of the worst advice I see dished out involves tires. Just because little Timmy says his tires are great doesn’t mean that he isn’t simply biased towards what he owns. Little Timmy might say tires from brand X rule, but we don’t even know if he really has anything to compare them to. Take advice you hear online about specific tires with that proverbial grain of salt. If you crawl in comps or with a club, watch the other trucks and see what works. But, don’t just watch, listen. Tires that grip, don’t chirp and spin on the rocks. If you don’t crawl with other people check out these tire reviews:
- Pro-Line Interco TSL SX Super Swamper XL 1.9 Review
- Pit Bull Rock Beast II 2.2 Tire Review
- Pit Bull Rock Beast 1.9 Tire Review
POORLY PLACED SCALE ACCESSORIES
If you’re going to add them, consider how their placement will impact your vehicle’s center of gravity. A roof rack is the easiest place to add scale accessories and, of course, the worse. Resist the temptation to add every scale doodad you can think of to the roof rack. Keep scale accessories to a minimum and keep them low. If you run a full spare, don’t use memory foam in it. Look, you’re not really going to get a flat and memory foam weighs a heck of a lot more than standard foam.
WRONG POWER SYSTEM
Adding a powerful system isn’t as straightforward as many people think, so just as many people end up getting it wrong when picking out new gear. Think of a power system as a four part system—motor, speed control, battery and gearing.
The motor is the first piece people think to replace in the search for more power. Going with a higher Kv brushless system or a lower turn brushed motor means more power that will deliver the wheel speed that is all the buzz. Contrary to conventional wisdom, go with a low Kv motor and try to find a 4-pole motor. The 4-pole design will make more torque and run cooler. If can’t find a 4-pole, it’s okay as the main goal is to keep the Kv low. Also, if you’re going brushless, you have to go sensored–end of story.
For a speed control, make sure it has the ability to offer instant reverse and has adjustable (and strong drag brakes). I see a lot of people with waterproof systems (usually borrowed from a Traxxas vehicle in their fleet) and while I love waterproof electronics, I wouldn’t give up instant reverse and drag brakes for waterproofing, so make sure the system you select has these crawling essential features. Factory BEC specifications are getting better, but I still suggest installing a Castle Creations CC BEC. The last must have feature is the ability to handle 3- or 4S LiPo packs. High voltage is the place to get power, don’t high Kv motors.
As I said above, I think of the battery as my real source of power, not my motor selection. While I don’t exclusively use MaxAmps.com batteries, I do these often because, while they do cost more, the quality is good and they are guaranteed waterproof. While I still run 2S packs in plenty of my rigs, a winning comp setup uses a 4S setup.
With a 4S battery sending all that juice to your motor, you can get away with some low, stump pulling gearing. It’s nice to have wheel speed when you need it, but torque still gets 90% of the work done. Gear low and crawl. Squeeze the trigger and enjoy that 4S lighting up your tires when needed. Added bonus, the low gears, high voltage and low Kv combination will run cool and last a long time.