I have a mountain bike that was my brothers and so I get a certain sense of joy riding it over one that I just bought at a store, I am considering purchasing some commuter tires as the "knobby" asI believe they are called are slowign me down, its takign me roughly an hour to get 7 miles with minimal stoplights all paved road. I hear about people getting speeds of 13 MPH, I can do that on the bike machine in the gym but not happening on my straight and narrow trail area that is wide open and free from cars.

So my tires now State 26 x 2.1

These tires on amazon seem to be a good tire to go with and they have a good deal of feedback, im open to other suggestions as well
http://www.amazon.com/Kenda-Bicycle-...pr_product_top

Also if this tire would fit, do I need to get a new tube as well?

Thanks in advance, and if it helps at all im in the 350 lb range. Riding 7 miles back and forth to work 98% pavement.