… Why 7800 RPMs?
Roy,
My Group-C Slot.it has 15mm wheels and turns about ~8500 RPM at the wheel (fast car); since the Scalextric has 17mm wheels, which will travel farther per revolution, I thought that 7800RPM would be a good start. (I didn’t math check it) — Thanks for asking, I will add something about it in the article.
… When you increased weight how did that change the ratio?
Weight only slows the car down, it doesn’t change the gear ratio.