Bike Forums - How much difference between knobbly CX tire & road tire of same size?

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- - How much difference between knobbly CX tire & road tire of same size? (https://www.bikeforums.net/commuting/1101790-how-much-difference-between-knobbly-cx-tire-road-tire-same-size.html)

Quote:

Originally Posted by noglider (Post 19464961)

Wow, glad to hear it. I had heard about them from [MENTION=45088]nlerner[/MENTION], I think. He called them "fast clouds." :lol:

I got the 35mm size which ended up being 37mm, and I can't fit them in my Raleigh. :( I should get another pair.

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.

Quote:

Originally Posted by Dunbar (Post 19465609)

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.

Quote:

Originally Posted by Abe_Froman (Post 19464559)

I dunno. I used to think a few watts makes zero difference...but I've sort of changed my tune - a bit. I started looking around for new tires at the end of last year. It became a bit of an obsession...I researched every single pavement tire on bikerollingresistance.com...and ended up switching from basically the slowest touring tire (Vittoria Randonneur) to the 2nd or 3rd fastest touring tire (Vittoria Voyager Hyper). It was a difference of 10 watts or so.

It's definitely noticeable. Not mind blowingly faster of course...I had on a no tread tire previously, it wasn't like I went from a 3 inch off road knobby to a racing tire. But I definitely felt it. Or...placebo effect from spending so much time picking out a tire? Who knows lol.

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.

Quote:

Originally Posted by chas58 (Post 19472089)

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.

Quote:

Originally Posted by Sy Reene (Post 19475250)

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