Why is weight so important to RC rock crawlers? The short answer is that the heavier a crawler is, the stronger the gravitational pull holding it to the ground. As such, heavier RC crawlers have better traction and can easily scale obstacles such as large rocks.
A heavy crawler is less likely to slip or tip over on uneven terrain. If too light, my crawlers frequently tip over backward when climbing steep inclines. That can also be a problem caused by excess weight high up in the chassis.
To figure out how much weight to put in RC crawler tires, you must first understand the dynamics of rock crawling. Care and precision in weight placement are vital. Too much weight can be just as detrimental as too little of it, and where you place it is just as important as how much you add.
How Much Does an RC Crawler Weigh? What Can You Do to Make it Heavier?
On average, RC crawlers weigh 30 – 35 pounds. The weight of a standard RC rock crawler can be 7 – 8 pounds, but highly modified models can easily weigh upwards of 80 pounds apiece.
Most of this weight comes from the batteries and motor—typically mounted on the rear axle—placing the center of gravity low but slightly to the rear. One of the reasons we add weights to crawlers is to counter-battery and motor placement that can make the RC drag backward when climbing.
Adding weights to the wheels is the best way to make a remote control crawler heavy. Weighing down the wheels improves their contact with the ground, which gives the crawler the traction it needs to drive on rocky surfaces.
I also recommend shifting the battery to the front if you’re skilled enough to do so. Crawlers perform much better with heavier fronts than rears. Couple that with a low CG, and they’re capable of some impressive rock-crawling feats.
How Much Weight Should You Add to RC Crawler Tires?
You should know two things right off the bat: the recommended weight distribution and weight types used on RC crawler tires.
The recommended weight distribution is 60/40 in favor of the front tires. The front tires should be heavier because the crawler needs good traction when climbing upwards.
There are different types of weights for this specific purpose. The most common are brass weights and self-adhesive lead strips, but there are more than a few ways to add some heft to a rock crawler.
How much you add to your vehicle depends entirely on its size and intended application. Brass weights and tire wraps typically weigh a few ounces each. I have crawlers with two full-weight wraps around the front wheels for a total of 7.5 ounces per wheel. Others only feature a couple of ounces’ worth of brass weights but still crawl over rocks pretty easily.
We use heavier weights upfront to offset the weight of rear-placed batteries and motors. Using the 60/40 configuration also gives the crawler more of a forward bite when going up inclines.
Even though 60/40 is the recommended configuration, feel free to tinker with the tire weights if you’re not satisfied with your crawler’s performance. However, you should know that there are perks and drawbacks to having a crawler that’s too heavy or too light.
Pros and Cons of a Lightweight RC Crawler
Light crawlers are mainly optimized for speed, so they’re quick and exceptionally good at clearing gaps. On the other hand, they’re also prone to tipping over when going upwards due to weak traction.
Pros and Cons of a Heavy RC Crawler
Heavy crawlers are the best at what they do: climbing rocks. They are front-heavy, so they have loads of traction for climbing up inclines and scaling rocks at low speeds. Unfortunately, the excess weight wears down the tires faster and slows down the vehicle.
What’s more, you need a powerful servo to exploit your weighted tires—otherwise, there won’t be any improvement in performance.
Types of Weights for your RC Rock Crawler
Brass weights like these Benedict Harry internal wheel weights go on the rim of your RC crawler. Each adds 2.26 ounces (64g) of weight to the crawler. This is the way to go if you want a quick and precise way to increase your crawler’s weight. It is cheap, effective, and neat since the rim weights remain hidden inside the tires.
Self-adhesive lead weights
Another way to weigh down your tires affordably is using lead weight strips. These CK Auto stick-on lead weights are perfect for RC crawlers. They have a sleek, low-profile design that blends in with your tires, so you can add as many as you need without ruining the look of your RC crawler. Each strip weighs 0.25 ounces (7g), and a pack contains 48.
Some drivers elect to mount metal plates or ballast on the chassis to weigh it down. It’s a little more complicated, so make sure you know what you’re doing. The benefit of this method is that it allows you to maintain your crawler’s original look.
Why You Should NEVER Use Water
Some RC drivers put water in the wheels to weigh them down. That might sound like a good idea, but it puts your tires at risk of quicker deterioration. Water can ruin open cell foam if given enough time, so it can break down the tires and subsequently affect the crawler’s performance.
Tips for Improving Traction after Adding Wheel Weights
- Switch to aftermarket tires with deeper treads to gain a better grip on uneven terrain.
- Wider tires have a larger contact area with the ground, offering more grip and stability. The same can be said about softer tires, which deform more easily, maximizing ground contact.
- Adjust your suspension setup to be softer to improve traction at low speeds.
- You can also install a differential lock, which locks both axles to turn at the same speed. This helps climb steep inclines and crawl over rocks at low speeds.