Andy,
I've been able to do a lot of testing the past two weeks running rubber tires on carpet with my US kit.
Keep in mind that I'm now racing in a 19t (or brushless 4300) rubber tire class on low bite carpet. We haven't agreed on a spec tire yet, and several of us have been trying CS27, RP30 and Sorex 28r pre-mount tires. I was able to test with the CS27 and Sorex 28r tires the past two weeks and found that the Sorex's are better so far. I should be able to test the RP30's later this week before this weekends race.
I was quite surprised at how the setup has developed, given that I have a few stipulations on what I do not want to change (US spec chassis/top deck, XH arms, front diff with layshaft one-way and used, but free, DNA1 bodies
). My goal is to be able to run the same car in both foam and rubber classes from one week to the next, without having to re-build or change much. Less than 30 minutes, including the use of the Hudy setup station & tweak board, is all that is required with the changes I've come up with so far
The anti-roll bars worked wonders for me as I settled on a 1.6mm front and 1.2mm rear. With these, I am able to use slightly stiffer front springs (dark blue) and much stiffer rear springs (also dark blue) as well to get quicker steering and more rotation from the suspension. Even though the previous setup I posted worked well enough for a club race, this new setup is much easier to drive and seems to generate more corner speed and even tighter lines with the rubber tires. My motor is coming off the track an entire 40F cooler after a full pack as well, without any change in gearing. Here's the setup:
xform/index.php?act=view&ID=445&setup=t2_007
I'll reserve final judgement on it until after this Saturdays race though. Gotta see the actual lap time differences.