Here is a link directly to HPI for the 31mm Vintage D Compound tires - (
http://www.hpiracing.com/products/en/4792/).
The insert on these tires are a soft foam and the outside side wall on these tires is fairly tall. I've only raced with the treaded tires, but I will say that this design does tend to have a little bit of roll. However, once you get a setup that works for them, the rear has plenty of grip. Granted, the USVTA motor rules create slower overall speeds in the straights, but the handling in the infield is on par with much faster classes.