Originally Posted by BigmountainVMD
I love that you used this example because I have done a lot of research on this for my car. Cost is not worth the benefit, but it is funny to see how much people will pay to reduce unsprung weight and rotational mass. It's extra funny, because the newest model is about to be released in EU (VW) and the new chassis is supposed to knock off 600 lbs from the car... People are paying 600 dollars for lightweight flywheels and 1000s of dollars for lightweight wheels that give them maybe 20 lbs weight reduction and 10 more hp at the wheels.
Yeah I was right into cars for a LONG time! Still work on my old beast and engage in car forums but not so much anymore. The physics you learn about when debating car stuff is really interesting!
The fact that rims and tires are both unsprung AND rotational weight makes them arguably the single most important tuning feature on a car. It always kills me that people go +2 or more on the rim diameters, and extra wide tires saying that it increases handling. Unless you need room for a big brake kit, the lightest factory size or +1 rims and tires are arguably going to be the best handling set you can get for your car!
Originally Posted by hktrdr
Don't agree with that. When boarding we are not really moving our legs the same way as when we are walking, i.e., with knees and hips being the fulcrum of the movement.
Hmmm, I see your point. And on-piste that makes sense. But when the slopes get rough our legs are acting more like suspension. When you're going over moguls, or reacting quickly in the trees you're making lots of quick motions in many directions with your legs.
Going to the next discipline, if you're in the park doing spin tricks, weight on your body would be close to the centre of gravity, while weight in your board/bindings/boots would be much further out. Watch a figure skater spin, and when they pull their arms in (i.e. all the weight coming towards the centre) they actually accelerate without putting any more energy into the spin itself. This is why even identical model boards will be much easier to spin if one's shorter, all the additional weight is out at the tips.
Actually this leads into another theory of mine, the extra wide (24+") stances that some guys ride with now actually hurt their park performance. The bindings, boots, and your lower legs are that much further apart making it take more energy to spin at the same spin speed.
Here's one last caveat: Through rough terrain I'd rather a stiffer heavy board, than a soft light board. But if I could have a stiff light board I think I'd rather that!