Hi,

It is a noob question.
My current bike has Kenda Small Block 8 700x35 tire (350 grams).
I'm considering changing the tire to Conti Gatorskin 700x25 (250 grams, folding).
Does this make a big difference in performance?
I'm averaging about 17mph at a flat surface with Kenda tires.
I wish to improve the speed at about 20mph.

Thanks!
and Happy New Year!