8% of 18 is 1.44 and 12% of 18 is 2.16, so just with an improvement in riding position, which is 100% free, a rider could go from 18mph to 19.44mph-20.16mph for FREE. . Any cyclist with any experience riding while being timed, or with a speedometer on their bike knows this. And the faster you go, the more important it becomes. So just like in the Wizard of Oz, you had the ability to go 20mph all along Dorothy, you just have to adjust your riding position.
I just did a 12-mile TT at an average speed of coincidentally, 19.4xmph on the yellow Huffy ten-speed wearing cut-off jeans and a cotton t-shirt, flat pedals and sneakers, and the only reason I got that speed was by riding with my body as low as possible. If I keep training and have no health setbacks, next year I will do it in 20.4 mph, and it will be at zero cost to me except for the time training and getting used to riding in an "aero" position, not because I dumped cash into a lot of fashionable and trendy bicycles, clothing and other parts.
