I have been talking with my friend Greg Stuart from Skat-Trak and the rotating mass thing is a big topic and Greg started to put this together so people can understand a little better the effects of Weight and rotating mass. Like Gregs desert race quads for example big heavy tire with beadlocks,tire balls in them for running flat if needed. Greg said bike was a turd in acceleration and when they would put it on CT Racings Dyno and swap over to a light set of Rims and tires it would Rpm instantly and feel like a Rocket LOL. Greg Was like man I want to run those tires in the desert but he knows he would make it about a mile out and get a flat. So no good LOL.
A rotating mass does not really consume or dissipate energy. A rotating mass stores energy. The stored energy can even be harmful, reducing acceleration or braking.
Accelerating an unnecessary rotating mass requires energy, and the acceleration process saps some of the horsepower we have available to accelerate our vehicles. Reducing available horsepower affects acceleration in a very predictable manner, and the horsepower amount needed to spin something up gives us some feel for how important a part change might be.
Four things determine the effect of rotating mass. Every one of these things is important:
- How quickly and often a rotating mass speeds up or slows down. Every time it is forced to speed up or slow down, it takes or releases energy.
- How heavy the rotating mass is. More weight (with no other changes) stores or releases more energy.
- The rotating weight's distance outwards from the centerline. The further out, the more energy pushed in and out of a given weight.
- How fast the weight spins, or the speed the weight travels in a given circle diameter. The higher the RPM, the more energy stored.
Number 3 on this list is the most important to consuming energy (horsepower) when looking at your tire and wheel combo. A 20lbs wheel and a 15lbs tire (total 35lbs.) will take less energy to rotate when compared to a 15lbs wheel and 20lbs tire (total 35lbs). Even though the rotating mass is exactly the same weight, the weight of the tire is further out from the centerline so a heavier tire will have dramatic effects on energy required to accelerate or to brake.
Why give away horsepower accelerating a heavy molded casing tire. Put more horsepower to the ground using a lighter tire/wheel combo. Skat-Trak has the lightest sand tires on the market. Our tires are typically 20% to 50% lighter than out competitor’s tires.
If you can take 8lbs of weight of each rear tire and 6lbs of weight off the each front not only has it made your side by side 28lbs lighter, it has taken 28lbs of rotating mass off your driveline. This will put more horsepower to the ground, be easier on your drive line, u-joints and shafts, the drive belt, and clutch system.
Our manufacturing process allows us to only add weight to the tires with the selected amount of paddles only. A molded casing tire is wrapped completely with rubber and a mold encases the tire while the rubber forms into the mold and creates paddles. This allows not only rubber for the paddles but also in the valley between the paddles. This creates a very heavy stiff tire and a lot of unnecessary weight at the furthest point from centerline. So there ya go a little more info to chew on.
