That's because there's MORE POWER.Which size did you get? 235/60R18? The recommended tire size for the SP is now 235/60R18 or 255/55/R18. I went with 225/60R18 (WS80) on my SP and they seem to be wearing more quickly than the 235/55R18 (DM-V1) that I ran on my RT.December purchased 4 Blizzaks and wheels from Tire Rack. I have a 2016 Charger R/T R/T. I live in Minnesota and have had no problem with the rear wheel drive. I downsized 20" to 18" but kept rolling diameter the same. Their Great!