It’s important to make sure your car is exactly 5 ounces on race day. But I’d suggest keeping it slightly underweight until you get to the race. It’s always easier to add weight than it is to remove it.
Last year our Scout District race was held outside on a car lot in April. Almost every car that showed up was weighing in at 5.1 ounces — a tenth of an ounce too heavy. One disgruntled father set out to prove that our scale was wrong and produced a 5 ounce brass tare weight. We put the weight on the scale and it came in at exactly 5 ounces. The scale was right, all the cars were too heavy.
Every one of these cars had raced previously in their Pack races. Were the scales at all the other races wrong? Had everyone added weight between races? Why were they coming in so heavy?
Most pack races were held in the winter and early spring when the air was drier. The combination of the more humid air in April and the race being held outdoors caused the cars to absorb just enough moisture to tip the scales. Racers and their parents were scrambing to remove weights with drills, by breaking off car parts, and other extreme measures. If only they had an easy adjustment method.
Previously I suggested drilling a few holes and plugging them with screws. Put a tenth of an ounce of your weight in these holes. Then on race day, you can add and remove weight easily by simply dropping weighted beads into those holes. That method works and has served me for years, but I’ve got another method I’m using this year.
Hardware stores carry lead tape for use in balancing fans and other applications. This year our cars will be built to weight 4.8 ounces and we’ll have plenty of lead tape on hand. A few strips on the bottom of the car will push the weight to the limit. And if we end up too heavy, we can simply trim a little of the tape off.