All I can say is that I race at the same track 95% of the time. Its outdoor and most of the year (6 months) its ultra high traction sugared bluegroove. Spring its medium bite bluegroove, and winter its low traction wet. The track temps have a huge range from the 20's in the winter to the 100s in the summer. The high desert is an interesting place. As of this year I have sold off all of my RM cars as I have found that although it seemed as though I could drive my RM more aggressively on the wet track my lap times were slower than they were with my MM cars. My personal preference is for MM on all surfaces. It requires more set up changes but the results have been better for me. I believe there is a component of driver skill and car set up involved as well.

As stated in above posts we have tried a number of things to increase what we percieve(d) to be traction (you can call it whatever you want) by using full square packs, keeping steel parts, and adding brass accessories. We have found that heavier cars hold the track better when the track is wet, freezing, or both. We have also tried to run 4wd fronts and that seemed to work for some people but not everybody.....we even use combos of open and closed cell foam. The one thing that was universal is that lugged tires like Holeshots worked best. There were larger lugged tires that worked well too but I can't remember which ones off hand.

I don't really want to get into defining traction but I will say that by adding weight you increase the amount of weight per square inch of tire contact patch. If that doesn't increase traction it does something akin to increasing traction. Somebody above was talking about a thinner tire provides more traction.....sort of. This is RC racing. Farm trucks and tractors can run a thinner tire because they don't turn at high speeds but the fact remains that there is more weight per square inch on that thinner tire it theoretically helps it dig in to wet earth better....snow and sand might be a different story.