H= up to 130 MPH rated V= up to 149 MPH rated Generally, a V will handle better than an H. You didn't say what vehicle you were going to put the tires on. I have read, on this board, that the 512's aren't all that. My mother has a set of the Triple Treads on her Camry and is pleased so far. Triple treads are not the same as the Aquatreads and are supposed to be far more advanced. No experience w/ the Michelin. I'm sure you have seen the reviews at the Tire Rack, but if not, go there and read away. The 0+ size would actually be a 215-60-15 although you may get away with the 225-60-15. Discount Tire has a calculator to help with speedo corrections with 0+ sizing. The 215-60-15: Speedo reads 65- you're at 64.16. The 225-60-15: Speedo reads 65- you're at 65.36. The diameters are very close. Just make sure the 0+ is appropriate for your rim size.