On 200TW tires: That's the standard minimum TW in most pro-touring series. Also note that even SCCA is moving their street tire classes toward 200TW tires. Unless things change, in 2015 all street tire SCCA Solo classes are going to require 200TW tires. 200TW is becoming the standard. What difference does it make as long as everyone is on the same TW?
Problem is that the 200TW is not a standard in of itself. Meaning that a 200TW tire by one company is not the same rating as one by another. Tire companies get to set up what 200TW means to them. Some companies even use a different scale for different models of tires. This number is only useful for relative readings within one manufacturers line and sometimes tire model specific. The scale one company uses is not the same scale as another. Its a basic problem. Not until an adopted scientific standard that is used by all companies will 200TW mean anything. At this point it is fairly arbitrary other than it means a performance/competition type of tire.
