Have ridden on this tire for 18 months in 28 width. Have always ridden 23 to 25 but after doing some more research decided to try the 28's. As with many things in life it's hard to admit that everything you thought you knew was right is proven wrong when you finally give in and try. These tires are not slower, they might be a little heavier but not enough to make a difference for most riders. Their toughness is amazing. I finally decided after a summer of riding to buy another set in preparation for spring. The current set has multiple slices that would have flattened other tires.
For past 5 years or longer I have ridden on another brand tire, I was satisfied. Bought a pair of the Grand Prix S II's, and have only one of the two currently installed (on the rear). I immediately noticed a nicer ride, felt stickier too. Definitely a better ride than what I was accustomed to.
I'll go out on a limb without any empirical evidence at all - the tire seems faster. Just a a couple rides and will be changing the front soon - so we'll se about that. Have to give them a season to see how they hold up. But so far - nice tire.
Amazing product. These are the only tires Ill ever need or want. As advertised. I only ride about 1,000 miles a year, but no punctures over last 2 seasons. And I ride on some roads. Ill give 5 stars because these Continentals are perfect for me.
I have Conti GP 4000 S on several bikes. They are my go-to tires for my rain bike, road racing bikes and tandem. I have used them in 23, 25, and 28mm widths. I have long loved the feel, traction and durability of these tires. Puncture resistance seems really good, too. The only improvement I could think of is for Conti to make a tubeless version available!
I have had two sets of these tires on my BMC Team Machine SLR01 in the last 18 months. They generally last between 3500 and 4000 miles. During that time I have had only one flat tire, and that was largely my fault, as I was running too low pressure and got a pinch flat. I have absolute confidence in these tires under any road conditions. They cling to the road and never lose traction. I wouldn't put any other tire on my bike.