Finally got a bike.....tire question
 

I picked up my bike last night. The tires hold air(tire calls for 60-80psi, so I went with 70psi) and they don't seem to be in terrible shape, but there are some cracks in the sidewall. I figure I ought to get some new ones before I head out on my 13 mile round trip commute, and keep the old ones as spares.
My current tire size is 700x38. Should I get a smaller tire? If I am correct a smaller (narrower) tire my potential speed will increase?
My commute is all pavement....a couple of potholes but I can easily navigate around them. I want to make sure that whatever I get is bombproof and affordable.
Can anybody make any suggestions?

My bike came with 38s as well, i swapped them for 23s. Not sure about speed but they probably help.

Bombproof and affordable? Hmmm.... I don't know about that. It's been my experience that bombproof tires generally run about $35-$40 each. You can get away cheaper if you're willing to change a flat now and then.

I got Continental Ultra Gatorskins, which I like a lot, for $35 each. They don't come any bigger than 700x28, which may not fit your rim. I got my wife a pair of Schwalbe Marathon Plus, $40 each, on the recommendation of many people here, but I haven't put them on the bike yet so I can't give any direct feedback other than to say they are available in wider sizes.

I would guess that anything claiming Kevlar belting (and may even just "puncture resistance") will be decently reliable as far as not getting flats. As far as width, narrow tires that can be inflated to higher psi roll better. Wider tires with lower psi are more comfy to ride on. It's a trade off.

going from 38 to 32 should make for a livelier zippier ride, all things being equal. 23 sounds likely too skinny.

My rims are Matrix 750's.....standard with Trek bikes from what I've read.
My tires are Bontrager Select Invert.
if that helps any.......

I've found that on my road bikes I prefer a 32mm. I haven't tried anything bigger because none of my bikes have enough clearance for them along with fenders. On my mtb commuter, I have 2.0 Big Apples and they are great for that bike. On my favorite road bike I have 32mm Panaracer Paselas and I love them.

Tire stuff
 

Your rim width should determine what is safe in regard to tire width. I'd say if the rims are wide enough a 32 mm is about the best compromise and I've had great luck with Panaracer Urbanmax tires plus regular Panaracer Tourguard Paselas. They are light enough, fast and tough. I just purchased some 27 x1-1/4" Paselas for $10 each. I have Schwalbe Marathon 40mm tires on my Long Haul Trucker and they seem flat proof for the most part. Depending on your weight you can safely go to a 28mm but there is little reason to go to less than that, unless you are actually racing or weigh under 125 pounds. Speed gain on a normal commute with skinny tires is often outweighed by the time spent on the side of the road fixing flats or the cost of wheel abuse, due to lack of sufficient air volume to protect them.:thumb:

I weigh 210lbs

Very exaustive explanation of tires, pressure, etc:

http://sheldonbrown.com/tires.html

While I'm looking on Nashbar and we're on the subject.....any tube reccomendations?

I'm actually there right now. Lot of good stuff. I also picked up a book today: The Bicycling Guide to Complete Bicycle Maintenance and Repair: For Road and Mountain Bikes. It was a toss up between this one and the Zinn manual. This one just seemed a little better to me, mainly because of all the pictures.

I just figured that you guys are all experienced riders with first hand knowledge, so who better to ask? Standing on the shoulders of giants, so to speak.