I have 1.5 wide tires on my R40 and was wondering if it would be a problem to put some really skinny tires on it? I come from mountain biking and am used to fat knobby tires. My friend, on his DF road bike, pedals effortlessly on his thin tires and I have to pedal really hard on my bent just to keep up. What are the advantages/disadvantages to really thin tires? I only ride my bent on roads and paved trails. I have a 16" wheel in front, would that be a problem?