I've been riding on 700x23 Conti GP4000 ($65-70 per tire) on my Litespeed for several years. Switched to Conti GP 4 Seasons ($70-80 per tire) last year.
My Felt that I bought in October 2011 came with 700x25 Vittoria Zaffiro Pro tires ($35 per tire). I'm not surprised that the ride is more comfortable but I was surprised that my average speed is faster than on the Litespeed with the 700x23 Contis. And I haven't had any flats either. Flat protection was my primary reason for buying Conti tires all these years.
So I purchased a set of 700x25 Vittoria Rubino Pro Tech tires ($35 per tire) for the Litespeed. I picked Rubinos because I had them on my commuter bike in 2001-2004 and only had one flat during that time.

If both brands offer good mileage and excellent flat protection then $35 per tire vs. $75-80 per tire is a no-brainer.

I normally ride on 25's and just changed to Ultra Gatorskins 700x25. It was between the Gatorskins and the Rubino Pros but I couldn't find them locally in a 25. So far they are working well and are very smooth riding. I hope they last as long as my OEM Kenda Kriterium's (3,100 flat free miles).

I've been telling people this for at least 20 years, but nobody listens...
Seriously, I've made the same 25-mile RT commute at least 2000 times since 1979, on a dozen bikes including a recumbent, on tires from 700x21 to 41 and 26x1.0 to 2.2. The very fattest tires are slowest, probably because of the low pressure (45psi). But the very skinniest aren't fastest, and my all-time record was on a 27-pound touring bike using 32mm Paselas. The engine matters more than the tires.
BTW, I don't believe anyone's ever ridden 3100 flat-free miles. Back when I used to keep track, years ago, I averaged about a flat every 50 miles, two to four a week. I don't remember ever going 250 miles without a flat and once had nine on a century. This is with good tires, not junk. Lots of thorns here.

Interesting discussion. First, I did about 1000 miles commuting this summer on 27"x28mm Pasela TGs on a road bike in mostly road-bike conditions. I had 3 flats, one the first day from a staple in the office carpet, the other two during the first half of the summer as I recall. (One of those flats was when some debris I didn't see on the road cut the sidewall, and I never found the cause of the other, a leak on the inside of the tube.) So I can say I did over 500 miles at least once without a flat.

I can't be certain from RonH's opening note what caused the speed improvement, whether it was the tire brand, the tire size, or the bike, or maybe just how good he felt on those days. Too many variables to make a valid comparison. But I won't argue that skinnier tires doesn't necessarily allow one to go faster.

I'm interested in the Gatorskin results though because I got a set of 700x25 on some wheels I bought, and I'm trying to decide what to do with them. I've never ridden on any before. Are they considered high-ish performance? Puncture resistant? Good, bad, or ugly? Actually, they are rather ugly.

I just put a pair of 700X25 Continental Gatorskins on my Look, and then rode it 50 miles over some pretty rotten roads. Oh, there was 5000 feet of climbing on that ride, too. I had switched the Look from Kenda Kaliente Pro L3Rs, 700X23. My main reason for doing that was that I needed to replace the tires on the Giant CFR Team I just acquired, and I decided that new tires should go on the Look. I went to my LBS, and they told me that two of our local race teams ride Conti's, the GP4000s, 700X25, not 23, because they felt the 25s give a better ride, last longer, and are JUST AS fast as 23s. The LBS believed that the difference between the Gatorskins and GP4000s was slight enough to where I wouldn't notice, but they did feel the Gatorskins would last me longer. So, I conducted an impromptu poll after getting that advice. I walked around at coffee after a group ride last week looking at the tires other people had on their bikes. More than half were Continentals, and many of those were 25s. So, I bought a pair, the Gatorskins. On the 50 mile ride I spoke of, I found them quite smooth, apparently free-er rolling than the Kenda's, and as for the 25 vs 23 argument - I didn't notice anything - I guess that's good, right?

I did ~6,500 miles on 700x25 conti gatorskins in 2011. My last rear tire lasted me just over 4,000 miles when I got my first flat - a nasty gash that meant I had to repalce the tire. I probably could have gotten another 1,000 miles out of that tire if it were not for the gash. My last front tire lasted over 12,000 miles (flat free!) when I replaced it. That tire would have gone further, but it was two years old and looking a little ragged, so I replaced it just because. IMHO Gatorskins offer a decent balance between rolling resistance, flat resistance and tire life.

I'm not surprised by Ron's report. I really like riding on 25s better than 23s. At the level most of us ride I don't think there is any speed difference at all. Can't say anything bad about Continentals but I highly recommend Schwalbe Ultremo DDs if you are feeling experimental. IMO they are very fine tires.

When I built up my Pinarello frame several months ago, I just hated the ride with the old D/A wheels and 23mm tires. I was almost to the point of stripping the bike and selling the frame. As a last try, I put on a set of 25mm tires that I had laying around that were going to be installed on the Madone, (but never got around to it because I went with different wheels on that bike). Boy, what a difference! I'm really liking the ride on the Pinarello now and am thinking about dumping the Madone or the Kestrel because I don't use them much anymore. Haven't noticed any difference in average speeds either.

I haven't had any experience with Gatorskin's. I ride on 700 x 28 Armadillo All Condition tires, (mostly to support my local bike shop). Granted they are a bit heavy, but so far flat resistance has been great - about 2500 miles and no flats. Will probably need to replace them soon, though, as the rear tire is looking a bit bald.

I am shocked that the OP was paying over $70 for GP 4-Seasons. PBK has them on sale for about $40 often enough to meet anyone's needs. I always have a few in the closet. Don't forget to get a coupon code.

I'm unwilling to change from the 4-Seasons because they are the only tire besides the Armadillos that can withstand the sharp grit my county puts on the roads during the wet season. While the Armadillos do last, they roll like a rubber coated, squared-off piece of concrete. I rarely use anything narrower than 25mm, but I am 200 pounds and our roads aren't exactly smooth.

This year old article explains : https://www.bikeradar.com/news/articl...e-myths-29245/

I run 28s on my tandem and always have a few hanging from hooks, so occasionally a 28 gets put on the rear of my road bike temporarily when I ruin a 25 and don't have a new 25 to put on. The last 28 I put on there stayed on for 2,000 miles before I took it off. To tell the truth, if there was a performance issue, I never noticed it and the ride is sooooo soft.

THIS

Without looking I can't tell if a given bike of mine has 23s or 25s on it. I tend to buy four or five sets when there is a really good sale on them. So, I have a mix of 23s and 25s. I do know my one bike has 23s up front and 25s in the back as an experiment. But until this thread surfaced, I had forgotten that I was doing this particular experiment.

Take a look at probikekit or ribble. These tires go for $40-$45 each with free shipping and no tax. Depending on the exchange rate, they can go much cheaper. I stocked up a few months agao when GP4000S were $30 each on sale.

I still have the tires in the shed and the original tubes on my bike. You are more than welcome to come and inspect them for any signs of a puncture.