Not to be too rude, but why? There are plenty of gravel tires that will move fast anywhere that bike is meant to go. Pick a good all-around tire like the Donnelly X'Plor USH, there are other tires just like it, and it will do wonderfully on pavement and any rail trail. I've tested mine out on the Prince Edward Island confederation trail, the Erie Canal trail, several sections of rail trail in PA, and the gravel roads around my parents. Also had no problems riding the gravel bike on the roads and maintaining speeds close to the road bike, road bike is lighter, geared differently and more aero so some difference is to be expected but often only about 2mph slower. Just never had to worry about road conditions getting to the fast part of the ride. Found them to be a great install and just go ride tire without a need to swap something else on. I know Vittoria makes something similar as does Challenge, I'm sure other brands do as well. Personally, if I need to swap tires I found it was only worth it if I needed a significantly different tire, not just a slight size change.