Bicycle Mechanics - Want to change to skinnier tires, need help..

I have this bike http://www.bikepedia.com/QuickBike/BikeSpecs.aspx?Year=2003&Brand=Specialized&Model=Expedition+Sport&Type=bike

I want to get skinnier tires for it. But I don't know what size I can get that will work on the rims I have. This page really does not give a size of my rim, and I don't know how to find out what it is.

Can someone help me with their knowledge of tires and rims and point me too a few tires that are skinnier than what I have that I can switch too for easier and more efficient commuting?

I would really like to do the purchase and switch them myself rather than my LBS. I like my LBS, but it's would be cheaper to do myself...but I need some help finding the right size and type...

Can anyone help?

http://sheldonbrown.com/tire-sizing.html Go down the page to see the relationship between inside rim width and rand of tire widths usable. The outside rim width is usually around 4 or 5 mm more than the inside width. I couldnt get the link to your bike description to work. Smooth tires roll easier than nobbies, but wait for the nobbies to wear out before making the switch.

Is it more the nobbies than the width of the tires? Or both? My tires don't really have nobbies on them, but are a fat tire. I fixed the link I think...my tires are 26x1.95 So could I put any of these on my rims?

26x1.5 (40-559) 585g 65psi
26x1.6 (42-559) 780g 65psi
26x1.75 (47-559) 820g 65psi

I got this information from Bicycletires.com and used the # ISO559-26" Mountain Bike, Hybrid for my rim size, and then put in city commuting as my primary use. And these were a few that were given.

It's knobbies, width and pressure that make a difference. I put a set of 26 x 1.25, 90 psi, slick tires on my wife's old hybrid and she loved them. If your rims are narrow enough (20mm) you can go with some very narrow tires.

I went to http://www.alexrims.com/ and in the little search box put in z1000. It came back with a nice drawing. Sorry I can't link it directly since the page didn't jump to a specific point.

It's a fairly narrow section mountain bike rim with 19 mm bettween the clincher ridges. Narrow tires are not a problem even down to using the Conti 26 x 1 if you want.

A nice option I'm using and really like is Ritchey Tom Slick and 1.5 wide. Grips well, rolls nice and has no little holes to pick up small gravel and go tick-tick-tick-tick-tick-tick.... like the Tioga City Slickers do. Sad really because the Tiogas roll wonderfully as well. THey just pick up little stones and drive me mad. While you can jump curbs with these tire options I wouldn't slam them hard into them. Learn to pick up the front at least enough to lighten the impact and to unload the pedals to help the rear so you rock over curbs. Going off them isn't as bad. If you want a really speedy fast tire the Panaracer Pasela TG 26 x 1 1/4 is the one. Wicked fast, flat resistant and egg shaped so the tread is more narrow like you'd find on a 1 inch tire. Be extra careful with jumping curbs or BIG potholes with this one though.

My Trek MTB came with 26x2.25 (559 x ~57) tires and I eventually changed them to 26x1.25 (559 x 32) tires and they work fine. Bicycle rims are very tolerant of tire size.

You can get down to 26 x 1" mtb tires, if you want really high pressure skinnies.

Bontrager Road Warriors come I believe down to 1.5" and are completely slick. They're great. Good traction, good shock absorption, good durability. They're also like $15 each.

Does anyone know if I can go from 26 x 1.50" rims to 700c?

For that bike you're probably looking at 26 x 1.5 minimum. Speculation is moot anyways, when the tire is pumped up it can't be narrower than the rim - THAT is your minium tire width (this also accounts for dishonesty in tire sizing).

You can go down to 26x1.25" without problem. NO LESS!
That might be too firm for your taste, since you have to pump them up pretty hard. It all depends on your weight, road surface, comfort level etc.

Your current tires are considered to be a "Bike Path" tire. Good for pavement, hard packed dirt and little "loose stuff".

Have you tried pumping them to max pressure +5 PSI? SOmetimes, that little bit extra makes a tire roll much easier.

BTW, I use a 26x1.5" on the same width rim for my 230+ lbs. (+ up to 25 lbs. of groceries) It seems to be a good balance for my needs, sometimes dealing with rough textured pavement. A smaller tire gives me too much "road buzz" on my non suspension bike.

Does anyone know if I can go from 26 x 1.50" rims to 700c?

No. (I mean, yes I know, and no, you can't.)

You can go down to 26x1.25" without problem. NO LESS!
That might be too firm for your taste, since you have to pump them up pretty hard. It all depends on your weight, road surface, comfort level etc.

Your current tires are considered to be a "Bike Path" tire. Good for pavement, hard packed dirt and little "loose stuff".

Have you tried pumping them to max pressure +5 PSI? SOmetimes, that little bit extra makes a tire roll much easier.

BTW, I use a 26x1.5" on the same width rim for my 230+ lbs. (+ up to 25 lbs. of groceries) It seems to be a good balance for my needs, sometimes dealing with rough textured pavement. A smaller tire gives me too much "road buzz" on my non suspension bike.

Yeah, like I said, they really don't have the big nobbies like a mountain bike tire. And even with the tires I have, I can keep a pretty good pace at 13-15 MPH. I just thought if I went skinnier, I might get a little more. I will pump some more air in them and see if that helps.
Thanks

With lighter tires you will notice the bike has more nimble handling - easier to make a sudden swerve to avoid a rock or pothole.

Does anyone know if I can go from 26 x 1.50" rims to 700c?

It's possible but unlikely. First there would have to be room in the forks/frame for the 700c wheels. If they would fit then you have to worry about brakes. If your bike has discs then there's no problem, with v-brakes/cantis there's probably not enough adjustment.