Most people don’t start off in the hobby doing any sort of competitive RC such as racing or rock crawling comps. And while most everyone strives to have their RC truck at peak performance, competition is what really motivates us to get the thing dialed in, or at least shows us when it’s not. Running by yourself, you never really know how fast your truck is compared to others and, conversely, you never know how well your rock crawler crawls until you see what others can and cannot do. For example, I frequently see people show up to what is their first scale comp with crawlers they’ve had for a long time and have put many miles on. They’ve invested a lot of time and money into their rigs and yet they fail to keep up with the regulars. They, of course, want to know why? Besides comp driving experience, the answer is often that while they might have a good truck or the foundation for a good truck, running by themselves has never shown how capably the truck is or isn’t compared to other trucks. More to the point, solo running has never exposed its weaknesses. Instead of suffering through many unsuccessful comps always watching the same guys win over and over, we have the tips and tricks you need to know. Below are the top five elements of setup you need to address on your scaler if you want comp worthy performance.
There is a big difference between low weight and weight low. Right now, the current setup trend in the 2.2 comp world is super lightweight rigs. The 2.2 comp guys are shaving every gram they can. That’s low weight, and it’s good for 2.2 comp crawlers and wannabe models. Low weight, however, really isn’t a concern for scalers. Here it’s all about weight low, as in low CG (center of gravity). While you don’t want a pig that can barely move, you need not be too worried about your scale truck’s overall weight. Adding weight may be a very viable option, especially if you have scale accessories mounted up high (I’m talking to you, the guy with the fully loaded roof rack). Try this: take all your scale accessories off and weigh them. Now, add at least twice that weight at the axle or lower. Even if you don’t actually perform that exercise, that’s the mindset you need to be in. The easiest way to get in the general area is with heavy wheels. One of my favorite ways to get a low CG is with Vanquish Brass Knuckles. These heavy weights have allowed me to setup a 2.2-tired Axial SCX10 with a lot of ground clearance and still maintain stability. Axle tubes that insert in your axles are most often used to increase strength (and repair stripped holes), but they also add weight just where you want it. While I’m not a huge fan of aluminum axles that are exact copies of the original parts (it’s a waste to not take advantage of the higher strength of aluminum and reshape the axle profile), Vanquish offers some exceptional aluminum axles that are anything but exact copies of stock.
Bottom line: go easy on the scale stuff up high and get the weight you have to have as low as possible.
STIFFER REAR SUSPENSION
Despite the hundreds of posed articulation shots found on forums, I am here to tell you massive amounts of flex are not where it’s at. Your suspension needs to work, but it doesn’t need flex nearly as much as all those photos would lead you to believe. Besides never encountering an upright soda can on a comp course, excessive flex will most likely allow your front and rear axles to get you all twisted and bound up in uneven terrain. The reasoning behind the massive amount of articulation is that it helps keep all four tires in contact with the ground. Makes sense if you have open diffs, but when you have locked axles, it’s a lot less of a worry. Why let a tire fall in a hole and have to get it out when you can just carry it over the hole without skipping a beat? While you don’t want to have a rear suspension with no flex, having it setup slightly stiffer than the front is often beneficial. When the rear suspension is too soft it can cause or allow for torque twist and allow for chassis roll and unwanted weight transfer on uphill climbs. A soft rear suspension can also cause rear axle steer depending on your rear suspension geometry. Rear axle steer is when your rear axle twists in a way that it impacts your direction of travel as it articulates.
Bottom line: don’t worry about having lots of articulation and setup the rear suspension slightly stiffer than the front if possible.
STIFFER REAR FOAMS
This may be one of the best kept rock crawling setup secrets. When trying to conquer a steep uphill climb have you ever noticed what your rear tires do when they encounter the base of the obstacle? If it’s a hard climb, they rear tires twist and contort. While the front tires got push up and over, the rears often start twisting and squishing as the get bound up at the base of the obstacle. This relates to soft suspensions and soft rear tire setups. Think of it as torque or all that power you’re trying to put to the ground as taking the path of least resistance. Meaning if there’s grip to be had and you’re on a difficult obstacle, the power from your motor is going to squat and twist the suspension and do all sorts of evil things to the rear tire before it gets applied to actually moving the vehicle as desired. This is a case of too much of a good thing. The soft rear tires provide lots of traction—a good thing—but when those tires stick too well, the above described scenario happens. The ideal setup is to run a slightly firmer foam in the rear tires. Not too firm, mind you, but just not soft. There are a lot of foams out there. Compare all that you can get your hands on. You can also check out Crawler Innovations, which offers a wide variety of foams. Crawler Innovations has multistage foam (memory and standard foam), closed cell foam and a variety of all of the above in different densities. Pro-Line offers a dual stage foam for for 2.2″ tires in addition to their memory foams.
Bottom line: slightly firmer rear foams will help on difficult climbs.
The key to steering is really twofold. Well, you can make it more complicated, but there are two main points you need to address—steering throw and durability. Increased steering throw is achieved by using universal front axles and knuckles with more clearance. The good part about the knuckles is that all of the knuckles that offer more steering throw are made out of aluminum and far stronger than stock plastic knuckles. One of the absolute best choices for knuckles in Vanquish Racing 8 degree knuckles which have zero Ackerman for a tighter turning radius. Most universal axles also increase durability, but their main benefit is that the offer far more steering throw compared to dog bone style axles. When you combine these two items, your steering will be vastly better than stock. You will immediately notice a difference. Also, you if you haven’t already, go with an aluminum servo horn. There are a lot of choices, but Axial Racing offers excellent clamping horns that are a perfect fit. Further improving steering is done by going with a high toque metal gear servo, but once you start down that path, you will also need an external BEC. By far, the Castle Creations CC-BEC is the most often used BEC.
Bottom line: the foundation of a good steering setup are aluminum knuckles and universal axles.
The drivetrain components offered with stock rock crawlers have come a long way in a few short years. The Axial SCX10, for example, comes stock with a slipper and a far improved driveshaft design. Ironically, the slipper clutch is something we actually took off the transmissions we were originally enlisting for use in early crawlers. They idea of slip seemed like a bad idea. I can tell you now that a little slip is a good thing. Use that slipper. Most people don’t know this (now you do), but Axial’s slipper assembly actually spins truer than its one-piece plastic spur gear mount. Driveshafts designs such as Axial’s WB8 mean you can run it pretty tight, but you should still use it. Early driveshafts designs popped apart and failed very easily. The WB8 style design stays in one piece no matter how hard you abuse it. You may put a nasty twist in the plastic splines, but that usually won’t end your day and after you replace the plastic shafts, you can slightly loosen that slipper clutch we were just talking about. The stock Axial WB8 driveshafts are good for just about every application, but there are all metal options that will not only not pop apart but will not twist. Whatever driveshaft you use, I suggest using a dry lubricant. Grease retains dirt and contaminated grease will do a lot more harm than good. Dry lube may not squelch squeaks as well as gooey grease, but I’ve had universal axles and driveshafts last for an amazingly long time while only using dry lube. Another running change improvement we’ve see made by Axial to its crawlers is a gear cover. When we were just puttering along strictly on rocks, we really didn’t need a cover. These days, we’re climbing up dirt hills, plowing through sand and blasting around in mud—all on one course–so, we need the gears protected. I haven’t really seen too many spur gears bite the dust while on course, but if you don’t have a gear cover, get one.
Bottom line: make sure your SCX10 has all of the updated drivetrain components—slipper, WB8 driveshafts and gear cover.