Hey there ROJA!

Wider tires are ideal for most neglected city roads, today. Some cities have roads as bad as some rock-filled mountain trails. Riding your mountain bike with wide tires sounds like a better idea, to me. Wider tires are going to be more hazard-free, you'll therefore have fewer flats, and much greater traction. Besides, exactly how much time will you save by switching to thinner tires?

With city traffic and stop lights, you'll most likely break even on the time bet. Speed is for racing bikes aided by skinny tires, that offer less road resistance. The faster road bikes also have lighter aluminum and carbon frames. Having a lighter frame and thinner tires does not IMHO equal an efficient or practical commuter bike for most urban road conditions.

If you commute on super smooth roads, that don't offer much in the way of road debris, cracks, cobble stones, and surface diversity, then the skinny tires will make you feel great as you fly on our cities streets.

A rigid fork on your mountain bike and MTB type tires will suit your daily commute just fine. Many people commute quite successfully on MTN bikes!

As a matter of fact, you can successfully commute on just about any type of bike.



However, you might want to remain mindful, that just because any bike can be a commuter bike, NOT all commuter bikes are "City Bikes"!

- Slim

PS.

A fifteen-mile commute each way, is nothing on a nice solid MTN bike!