Granted, the tires pictured above don't look that skinny, but they are narrower than what comes stock on most of our mountain bikes. Many of our customers realize that the mountain bike they use for fitness riding on paths and light trails, for their daily commute, or to run errands has tires that are a bit of overkill for their purposes. The truth is that many of us don't need a wide, knobby tread for our everyday riding, and on pavement (and even dirt and gravel much of the time) narrower, 'slicker' tires with higher PSI are much more efficient.
That's why we stock a good selection of 26" tires that are well-suited to riding around town. They start at just $15-25 each, and for the much improved ride you'll experience in many conditions if this is the sort of riding you do they're well worth the price.
It's also worth pointing out that we'll happily swap out your tires at the time of purchase of a brand new bike to set the bike up to work best for you. If you need skinnier mountain bike tires that's what you'll get, at no extra cost, or for the difference in cost between the stock tires and the new ones if the new ones are worth considerably more. Just thought you should know.