In the dutch mountain bike scene pretty much everyone rides on Schwalbe tires. When I got my road bike, I turned naturally to Schwalbe for my tires. The Ultremo looked like very promising tires. Also since its a road bike I figured thinner is better, so I went with 23mm Ultremo ZX. I liked the tire. It rolls really well and the feeling of grip was impressive. It does have one problem though, flats. I got a flat once every 150km.
I am by no means a small guy. I can imagine my relative high weight (90kg) makes me more vulnerable to flats. Still, these were a lot of flats I was dealing with. I decided it was time to look for another tire. A friend of mine had a pair of Schwalbe Durano that he didn’t use so I bought them from him. They were not really grippy, and they rolled heavily, but at least I didn’t get flats anymore. I figured in 2013, there has to be a better tire than this. It was time to jump ship and try Contis. I have heard a lot of good things about the GP4000S and so decided to go with that.
Another thing to consider was the width. I had a long talk with a friend of mine who is both a cycling enthusiast and a Dr. of Physics about roll resistance and tire width. He convinced me to try wider tires. Since I already decided to buy new tires, I was going to get the 25mm variant. After cycling with them for two weeks, here are my initial impressions:
The rubber feels sticky
Just touching the tire feels like it will stick to your hand and will not drop if you let go. It really feels that sticky.
Feels a lot more massive
This might be more due to the shift to 25mm but these tires feel a lot more massive. The difference is much larger then one would expect. The bike itself actually feels more massive. It might not be what you like but for me, as a mountain biker, its a great feeling.
Great confidence in turns
Combine my first two observation and you get a tire that gives a lot of confidence in corners. I am cornering faster and smoother then ever. The bike really feels on rails
With all that grip and massiveness, I feared that the tire would roll heavily. Nothing is further from the truth. I will say that the Ultremo feel like they roll a little faster. This tire is however, by no means a heavy roller. Its smooth and it rolls really really well.
All in all, I am more then impressed. Looking forward to seeing how much I like this tire after I have gotten a few thousands KM into it.