This past Sunday I was able to firm up some theories on what works with the Tamiya rubber tires for the 104. Lately, I have been getting the feeling that "oily" tire preparations of any sort make the car get greasy or loose feeling. That includes all of the Tire Tweak, SXT 2.0, Paragon, Jack, etc. After using Sticky Kicks Blanco, a treatment similar to Buggy Grip, but less aggressive, I felt that any oil type additive was leaving the tires somehow more slippery or greasy. The "softener" type additives penetrate the tire, but they flash off quickly the same way motor spray does.
Just to make sure I was getting a true result, I once again tried a oil type additive. The result was the same as what I have been getting all along, a sliding race car. Once I went back to the Sticky Kicks, that car was back to normal.
Speaking of Sticky Kicks, it produces a car that steers and has rear traction, but balances towards a bit of oversteer. I feel like this is a pretty good balance, since these cars are fastest when they have a lot of steering and you can be on power as much as possible. At the same time, there may be some track situations where it's more desirable to have a car with a balance toward understeer, or at least stability. At that point I would suggest just cleaning the tires with Simple Green. I tried this as well Sunday, and I was amazed at how much the characteristics of the car changed. It went from a bit on the edge of oversteering to locked down enough that I had to dial in dual rate to get the car through the corner. This is good however, if you're on a slippery track. Extra wheel throw is not efficient, but being able to jump on the power especially if the other cars are not as hooked up can be a big advantage. As the tires warmed up, the steering did get a little better. Simple Green is probably not a bad idea to start at a track with, and then move to other preparations as track conditions dictate.