Does Adding Ballast to Tires Help Trail Performance?Posted in How To: Wheels Tires on August 1, 2017
We spent significant time and effort making our Tracker project as light as possible (Part 1, http://www.fourwheeler.com/project-vehicles/1506-we-build-a-lightweight-fuel-efficient-daily-driverrockcrawler-chevy-tracker/). We were rewarded with a vehicle that is nimble and incredibly capable on the trail without requiring a V-8 engine or 1-ton axles. So why would we deliberately add weight? Good question.
Our first exposure to running water in tires was about 15 years ago at a rockcrawling competition. Joel Randall was a competitor at the time, but he is also a farmer from Nebraska. Randall had been putting water in the tires of his tractor for years to increase the traction and keep it from jumping out of the rows of his field. He applied the same principle to his rockcrawling buggy. Soon thereafter nearly all competitors started adding water, lead shot, or some form of ballast to their front tires.
The idea is that the weight added is as low to the ground as can be, lowering the vehicle’s center of gravity and making it more stable. Additionally, the weight is entirely unsprung, which helps keep the tires on the ground and increases traction. The downside? Well, that’s what we were looking to find out. We had only seen water added to tires for slow-speed rockcrawling. Would it ruin our Tracker’s ability to drive down the street? Would it scatter our front axle into little pieces?
In competition crawling, Dana 60 or comparable 1-ton axles with chromoly axleshafts and drive flanges are considered mandatory equipment for running water in the tires. Our Tracker doesn’t have a 1-ton front end; however, it weighs under 3,000 pounds and has a 137hp four-cylinder engine. The Tracker uses a Diamond Axle–fabricated housing that has a high-pinion Toyota 8-inch centersection with 5.29 gears from Nitro Gear & Axle. Admittedly we are pushing our luck with regards to this gearset. The axleshafts are less of a concern since they are chromoly Birfields and shafts from RCV. Similarly, the knuckles are Hellfire Fabrication (now owned by Ruff Stuff) 80 Series knuckles that use trunions instead of ball joints. In short, this is not your standard Toyota front axle.
Even with built axles we don’t recommend adding 80 pounds of ballast to each tire if you use your vehicle for daily driving at freeway speeds. Doing so would increase braking distances and the risk of losing control of your vehicle at speed. When the water gets unsettled in the tires, the result is similar to death wobble, which is no fun at all. These tradeoffs might be worth it, though, if you have a dedicated trail machine and are looking for more capability. Our Tracker has cutting brakes, selectable lockers, and a winch connected to the front axle to compress the suspension. Water in the tires is another tool in that toolbox. Still, we don’t plan on selling off our normal tires and wheels quite yet.