I currently have some Hutchinson Carbon Comp Black 700x23 tires on my bike. I want to get another set to use for training, or perhaps for racing - saving the Hutchinson's for training. The other set is also being purchased so that I have a spare tire for my first century ride (considered a training ride) coming up.

I do triathlons mostly, and I'm interested in getting into road racing and time trialing.

Several Questions:

Can I put 700x20 tires on my hubs? (bike nashbar has some on sale)

If so, what should I use the 700x20 tires for, racing or training? (I'll bet it's racing)

How much should I be concerned with tire weight? Again, bike nashbar has some great tire sales right now, but the various sale tires are about 50-100 grams heavier than the Hutchinsons that I currently have mounted.

Basically, can someone recommend a good combination of tires that will both work with what I currently have, with the types of races that I'll be doing?

Thanks!

No problem with the 20's.Probably best for time trial if heavy.Heavy matters little at steady speed,matters much in accelerating or climbing.

if you train on Heavy tires, your'e ganna be an awesome bike rider if you switch to lighter tire during a race, what i do for strenght building I ride my MTB w/ a bike carrier and I bring alone my son, the next day when I ride my road bike I certainly feel the difference, I am a a little stronger, so your idea is pretty good

for tire size, the width of your rims is really the limiting factor. Too narrow for your rims means potential rim damage.

Note also, smaller tires means less shock absorbing, which means wheel truing may not be as subtle.

How much should you be concerned with weight?
~Lower weight, of course, but don't be unreasonable, get a tire that is going to last for your intended use.

What am I riding?
~700x20 Specialized Team Turbo clinchers on Mavic Heliums. (found the set of STT's on ebay for $40) Before that, I was riding 700x23 Specialized Team Turbos on Rolf Vectors. Now, the Mavic Heliums have less rotational inertia anyway, but with the 700x20's also, I noticed an incredible difference...the bike just really wanted to go! I'd go narrower if I could. I've seen tubulars in 700x19, and they are higher pressure, so perhaps less rolling resistance there too...
I'm using Michelin Ultralight tubes, 72g each . Specialized makes tubes lighter than that, but I've been recommended against them.

My bike has Mavic CXP 21, 32H rims. Will they accomidate 700x20 tires ok?

You will ahve no problem.

I'm not sure you'll get much of a performance boost with 20s, unless they're lighter than your current tires. What model are you looking at? [BTW, a whole lot of people race on 23s].

I'm currently looking at these:

Hutchinson Crono Comp Road Tire

or

Hutchinson Crono Comp Gold Tire

There are others at bikenashber.com but I gotta start my search somewhere. I'm trying to strike that ever-elusive balance between price and functionality.