Originally Posted by
metalnut
Noob question... how do you tell which was affecting you when you get the car to the pit after the race?
compared to some of the guys on here, I'm a 1/12 scale baby. I did my share of asking questions and experimentation though, but my understanding isn't quite complete. One thing I know for sure, there is no 1/12 scale gospel, especially as I can't drive or examine your car in person over RCTech.
Quick Robin! To the Wall of Text!
As I understand it, racing foam tire on carpet means you will either lose, gain, or maintain traction and tire buildup to/from the track. Add to this how foam tires wear a small but not inconsiderable amount to reveal a new driving surface during the race, it must be race-ready as well. If your car maintains traction over the run, great! No problem at all. If you gain or lose traction to the track, there are several possible reasons why.
As an anecdote, if I were to run a double-pink, 35 shore natural rubber front tire with half-sauce on the inside and during my run the car lost steering at 6 minutes and comes off the track with rubber goop buildup on the unsauced part of the tire, I would guess that I either burned through the sauce or the goop made the car push. This goop can go either way in affecting grip, it may reduce grip or give even more steering you don't want, either way the buildup may be affecting consistent traction. To combat this, I could fully sauce the front tire to keep the buildup away, but this may also cause excessive front grip and affect the cars handling early in the run. If I don't think the goop is really changing the cars performance and I just burned through the sauce, or if there is no goop at all, I could continue half-saucing but sauce for longer, maybe even twice as long. If I decide that I want to fully sauce the front tire to keep it from getting any buildup, but I don't want to make other tuning changes to take the extra tire grip, I would switch to a harder front tire with more sauce for longer, or even a synthetic rubber tire like a Black with a full-width soak. A Black compound tire can have plenty of grip with a good soak.
As for exactly how you would GUESS which way to go, I would have to see the tire.
Back when I first started in 1/12 scale I found that a hard front tire favors my driving style and typical car set-up. I am a lock-to-lock driver which means my car performs best when it has a good transition from high-speed push to low-speed rotation at the corner apex. Soft natural rubber front tires like Pinks and Magentas tended to make my cars pulse-steer and even have a high-speed oversteer, making it difficult to drive the car efficiently. These days I almost exclusively drive hard front tires with lots of sauce.
Extreme cases this process probably won't hold up but at the club-racing traction level, it's taken me from being a DNF to competing.