Really?
Implicitly this means the traction control takes into account speed and factors in tire growth, wear, lean angle and fork/shock compression, all of which impact the effective diameter of the tires.
So let's look at some numbers to put things in perspective.
The tread depth of the 200/55 Pirelli Supercorsa is 4.75mm. If traction control is indeed sensitive enough to be significantly affected by a 5.5mm reduction in tire size, does that mean that it adjusts for tire wear or is it optimized for some very specific amount of wear and when tires don't have this amount of wear, traction control doesn't work properly?
Tires also tend to grow over time due to pressure and heat cycling. 3-8% growth is not unreasonable to expect. Does traction control adjust for tire growth?
For a 200/55 tire the maximum diameter of the tire is 25.66" (straight up and down), while the minimum dimater is 20.5" (full lean). This means when leaned over a speed sensor based on rear wheel revolutions reads a higher speed than when the bike is upright. The vast majority of operational diameters between a 190/55 and 200/55 is going to fall within the diameter range that you might see using a 200/55. Rather than rely on tire circumference as a parameter for traction control, I would expect it to use a 3 dimensional accelerometer to determine how leaned over a bike was and to use this to calculate the acceptable speed differential between the front and rear wheel before traction control takes effect. Speed differential alone between the front and rear wheels is not enough to make an effective traction control, since tire diameter varies significantly from full lean to upright.
While fork/shock compression and extension is not the same as ride height adjustment it can have some of the same geometry impacts. Assuming 3" travel, you get 76.2mm in range from full extension to full compression for the suspension. 5.5mm is relatively insignificant compared with the impact suspension travel can have on geometry. Unless traction control is somehow figuring out suspension compression and extension it is unlikely traction control is going to be significantly impacted by a 5.5mm ride height change.
Given the preceding it is very unlikely that traction control is sensitive enough to be significantly thrown off by going to a 190/55 tire. There are too many other factors which have much larger effects than this change for this change to be significant.
