Currently on my Dahon Speed P8 it came with Scwhalbe Big Apples in 20 x 2.0 tires. They are comfortable but not very fast. I have an average speed according to my bike computer of about 13-14mph. I would like to go about 18-20mph. Would switching to the Scwhalbe Marathon Supremes in skinnier 20 x 1.6 have me be able to do this ?? I know I would be giving up some comfort. Thanks for any info and sharing any experience in this.