On Wed, 11 Nov 2009 21:19:47 -0500, Kathy wrote:

I inherited a mountain bike from my son
and I need to replace the worn tires.

Could I replace the originals with a set of tires that are a bit
smother?

Just look for something with a continuous central flat ridge line. Much
smoother and quieter. YMMV, but you might have to look around a bit.

By the way, the tire are 26 x 2.125

That is a lot of rubber/nylon and air to revolve, not to mention arm
action in pumping them up. Come down to a 26x 1.75