noglider 

A few years ago, I bought three mountain bikes at the local police auction. Of course, they all came with knobby tires. I don't ride off road, and since they made a lot of noise, I figured they weren't doing much good. I got some slicks and inflated them hard, and yes, big difference. My wife isn't a serious cyclist, and she's very light and not very strong, but I decided to get some nice tires for her. I'll never forget what happened. I put them on her bike. Then we drove out to a nice remote area to start our ride. I said, "I'm not sure you'll notice the difference, but let me know."

She rode about 40 feet and said, "I notice the difference!"

Best upgrade for a bike. You really don't need knobs unless you ride in very loose stuff. I think a mountain bike with upgraded tires is a wonderful all-purpose bike. You can do just about anything on it.

I inflate mine to about 80 or 90 psi. I'm about 186 pounds. (I'm a guest here in the Clydesdale section.) I inflate my wife's to about 70. She's only about 125 pounds.