Originally Posted by bdmpastx

Sounds like the car is getting off the groove and loading the tires up with carpet fuzz or rubber buildup. Its hard to see it doing that sometimes unless you know what you are looking for. If it is good and then fades, it's all tires. Are you cleaning them really good after each run with a towel and motor spray then saucing? Also if you are saucing they whole front, that could also make is difficult to drive as the rear tires start to load up. The temperature and humidity also plays a huge role in traction on carpet. We find that the humidity increases bite and the cars seem to get faster as the night progresses.