Continental Grand Prix 4000s II Cycling Tire, Set of 2 Tires

I've done a few rides (100-150 miles each) in the past month in preparation for a double century. I purchased these tires with high expectations for the big day. They came just in time for me to put them on the night before. I noticed immediately the next morning how smooth they felt rolling along. They felt more comfortable and seemed to feel a little easier (less rolling resistance). Upon getting to the winding roads, their grip was spectacular. That is where I noticed the biggest difference. The day was going great right up to mile 137, where the rear tire sidewall blew out at 30 mph. Luckily, I was on a straight road, and the bike, even with the flat, was easy to control and slow to a stop. Happily, there was no damage to the expensive carbon rim, but the tire was beyond repair, having a big hole in the sidewall. I'm hoping that this tire just happened to be defective, as I really love the ride, and in all my riding, I've never had a tire do this before, especially on the very first ride! The front tire had zero issues. I'm going to give the 25C's a chance, before giving up on them.

After replacing a NO flats pair of gatorskins 28c, I am extremely pleased with continital gt4000 tires 28c. Immediately the bike feels more connected to the road with a stickiness sensation. Will take a 3hr ride for a more thorough understanding of why these tire are considered the best on the planet.I will be riding the highly modified 59cm 2006 Bianchi Veloce Disc AKA "Benito Mussolini"Update: After spending 3hrs up and down the hills of SF aboard the Gp4000s, Im very pleased with the handling and the confidence these tire provide. They have substantially more grip than gaterskins, which are very puncture resistance but are slippery as hell, down hills are not very fun or safe. With the Gp4k decending the same hills my focus is not whether my tires will give way but instead its how much I'd like to explore the limits of the bike. Leans are shallower, speeds are increased , and yet the experience is safe and controlled. The GP4Ks are the best clinchers, period.

These ride nice, unfortunately I had the same issue as other reviews. Bought them 7/8/17, put on a few hundred miles. Had one tire blow on mile 56 of a 100 mile race on 8/13/17. Was just going to buy another one, but noticed the sidewall on the other one is showing the wire. Just can't trust these.

So, I put these 25c tires on after a year or so on my Gatorskin 700x25c. I had read the other reviews which said they were prone to puncturing and thought "yeah, I know, it's a folding tire, you have to be a little more careful with them; you can't ride on any sort of rough surface, etc". However, these tires are so shoddily built that they're not suitable for any road surface at all.The first ride in, on a bike trail, I had a flat when I ran over a small pebble. The second ride, I had a flat in the other tire when, again, I hit a small stone. On that same ride, an even more serious problem occurred; going around a corner I had a blowout on my front tire, causing me to crash. The blowout was in the sidewall, and the tire was pumped up to 110psi, so I have no idea what the hell happened.I can only guess that the construction of these tires is "off" somehow. They have a very squishy/sticky feel through the corners, almost like the outer tire wall is disconnecting from the underlying subtire. The feel of the outer tire is so, so so, soft. It feels unlike any road racing tire I've ever ridden; and not in a good way.Anyhow, I'll be contacting Continental about these tires, and requesting a full refund. They honestly reek of a serious manufacturing/design error. They shouldn't be selling these; people will continue to get hurt if they do.

Update: Amazon and the Seller has warrantied the tires and I will get a replacement set.... I'm upping the review to 3 stars because I'm satisfied, but that still doesn't help the confidence in the product itself.... the service is 5 stars from BikeMe and Amazon, the product is still a 1 star at this point. I'll re-review the new replacements.Just installed these 8/20/18 purchased from Amazon as a pair in 25c size. The first few rides were uneventful except for this road noise up front I couldn't quite place and just figured it was the little extra bits of tread in the middle of the tire and after it wore off, I thought it would go away anyway.... I was happy for sure after 50 miles of 3 total 'test rides'.Last night, at mile 75 (total mileage on the tire) the rear developed a HUGE buldge in the middle of the tire... so bad it was rubbing my seat stay and I immediately pulled over during a 35mph downhill section. The tire was so deformed it would not roll through the seat stay anymore.... so I let over half the air out of it just to make it roll again and rode slowly home. So a total of 83 miles the rear tire is dangerous, and the front come to find out has had a small buldge on it probably from day one after further close inspection (the road noise initially was the buldge).I've submitted a request to the seller to see if they will warranty these, and I'll update my review if they make it right.... but as of right now, these are already off the bike and will never be installed again. Id hate to think what a blowout would do in a downhill, like I said.... dangerous!

I used to ride on GP 4000 tires all the time. The price was painful so last year I tried a pair of Michelin Pro 4 Endurance tires. Just pulled them off after the rear developed a small hole that began tearing more and wasn't looking good. I only got 2,025 miles out of the rear Michelin and it was already developing a flat surface and then developed the small hole that tore. Back to Conti's since I found a great price for a pair. They absolutely roll faster, picking up 1-2 MPH over the same route in the same conditions, and generally wear longer. Find a good price and go Continental Grand Prix 4000s II. Couldn't find enough reasons to try the 5000 series and rode with someone last weekend that said another cyclist tried them and said they were not worth the higher cost and would drop back to the 4000s again if one fails.