Originally Posted by RGMN

36 x 30 is 31.75 inches, 34 x 28 is 32.13 inches, so the 36 x 30 is slightly lower. As for which is better for hills, I couldn't tell you. My lowest bailout is a 34.5 inch (30 x 23), and I find it is only useful for climbing trees or moderate hills while having a heart attack. Almost all of my bikes have a low of 41.3 inches (39 x 25) which is more than low enough for me and the hills I normally ride. YMMV.