I'm actually used to a hardtail mtb with a rigid fork, so comfort isn't quite my top priority. In fact, the bike I'll be using these on is lighter and has a front suspension. I'm more concerned with speed; both acceleration (when I'm cycling through housing areas/city area) and top speed (for long stretches of tarmac sidewalks).

If I'm understanding this correctly, 1.5 or thinner will be ideal?