Just curious about this statement Reso, but how is this determined? I believe I know that all tracks can be different but where does the +/- come from, the location of the electronic eyes, or something completely different? When I was at MA and watching the pro races, John seen things with the track that quite simply I never even considered, like a dirty track as an example, I heard it when the cars ran but didn't know why. Quite honestly I thought there was something wrong with the car. Mr Chips said he cleaned wheels as best he could to assure a good run of each car. I'm a newbie when it comes to all of this and I'll ask questions as I learn more and more about this hobby. Thanks in advance.