Well Uber,
All arguing aside, I felt a nice increase in accelleration when I went from my stock wheels/tires to the enkei's and toyo's. VERY noticable.
You won't believe it till you try it I guess, but if you get some extremely light wheels and tires, you'll feel the extra pull off the line, no doubt about it. As well as feeling the quicker braking response. I know the grip of the toyo's had a bit to do with the braking, but not so much on the acceleration.
On my old car, I had stock 15" wheels that weighed in at 16lbs, the tires were some old generic crap tires that were actually pretty light, the combo weighed in at a mere 34lbs. I purchased some Konig Monsoon's and Toyo FZ-4's, and that combo weighed in at a hefty 47lbs!
I felt a HUGE difference in acceleration! It was a dog off the line, the car didn't have near the snap it used to, and braking was worse (front disc, rear drum).
I didn't really know what was going on till I found out about the weight difference. I also found out that it makes a much bigger difference on auto's due to the constant slippage of the TC.
Now, does 1lb extra of rotational mass mean 1hp lost in the drivetrain? It very well could, think about it swinging on that axis. A lot of leverage there for some pretty decent weight.
If you lost 10lbs on all four wheels combined, it would feel as little as a 10hp gain, just on acceleration, not overall speed or anything. Just as a decent intake will give you 10rwhp, you barely feel that, right? The lighter wheel/tire setup feels about the same, if not better, on acceleration only. If you get an extremely lighter setup, you KNOW the difference.
Rally cars also use this. They use EXTREMELY light wheels, they're constantly breaking them cause they're designed for ultra light weight. They would be strong as hell on street use, but they really aren't that strong on the rally circuits. Their wheels usually are around 12lbs for a 15 or 16" wheel.
This is personal experience, I've felt it on two completely different cars, one instance going heavier, the other going lighter. People on this board know I don't exagerate or BS.
Believe what you want, but don't reply to posts like this unless you have personal experience.
Kane