One of the best Ye Olde stories that I heard (I think it was from Lonny or RacinJ) was that at the first 1/12 worlds to be held on a carpet track, the carpet was so grippy that all of the chassis of the day were out of their comfort zone and scrubbed speed badly. I believe this race was held in Denmark, and it just so happened that the locals had a coin with a 0.250" hole in the middle of it, so people started bolting them to their axle as a flywheel to hold speed through the corners.
Supposedly its true, it was before my time though.