Yeah I got the 38mm, which is actually 40mm with their goofy sizing. Made me realize I didn't redish my wheel well enough at the end of fall before I hung this bike up. Tire is awfully close to the left chainstay haha. It does fit though...even with fenders. Barely.

I had 700x35 Voyager Hyper tires on a previous bike and the combination of lower weight and very good rolling resistance was impressive. I didn't think that they gave up much to my 700x25 GP4000S's in the efficiency department and they were quite a bit more comfortable.

Yeah. I would do the 28's if I ever do go that route..apparently their 28mm are abnormally large. It's why I was comparing agianst the Hypers which were one of the few good large fast tires I could find.

I agree with ya. I have a set of those Victoria Randonneurs. A bit stiff, slow, heavy. Came on a bike I bought, and I quickly took them off. They have *twice* the rolling resistance of the conti’s above. That is something I can feel.

Maybe it’s just me who can’t tell a difference in a couple watts (when I'm not racing). LOL. At 80 psi, the 4000s takes 13.7 watts. The 4 season 19.8 watts.

When I’m on the 4000s’ I put out the same power as when I am on the 4 seasons. So, the only difference I can “feel” is a slight decrease in speed. But I don’t measure it that precisely. I’m putting out roughly 250 watts either way, and it makes zero measureable difference in my commute time

Like Paul H said – when I take my deep lugged studded tires off, I go a LOT faster. But between the two continental tires, nothing I can measure in non competitive conditions.

What I do notice about tires, like the 4 season and the 4000 is:
• Volume (4000s is larger than named, the 4 season smaller).
• Suppleness (both these are pretty supple)
• Weight – how easy they accelerate and climb
• Puncture resistance (very different again here).
• Rolling resistance or cruising speed – not so much here.

FWIW there are also Randonneur Pros from Vittoria with 120tpi (vs. 30tpi of the non-pros). I've been happy with these. Actually, I noticed these are on closeout at Chain Reaction if anyone's interested at less than half price.

They are now called the Voyager Pro, I guess to reduce confusion with the Randonneurs.