Failed within 24 hours on 45mm tires. Postmortem showed failure at the nonelastic reinforcement opposite the valve. This area will not stretch when fully inflated, leaving two sharp wear points. These are probably good up to about 38mm tires.
I have used a variety of inner tubes over the last 50 years, but the Continental Tour 700 IMO is the best and a decent value as well. In thousands of miles I have yet to see any failure at the stem area (a weak point in any tube) nor have I had any pinch flats. I check the air pressure in both tires before every ride. All tubes leak and these are on the low end. I only need to add air ever other ride.
Just mount them with some talc powder and off you go! No worries.
If you cycle the distance on road touring and carry loads such as panniers this is a must tube! The rubber is a bit thicker and more puncture resistant. They are extremely easy to install. They can handle large pressure without stress. I tour all the time and find the regular 28X32 road tube to thin and they rupture because of the added weight on the rear tire. Therefore, I used to run the tire at a lower pressure. With the Conti Tour tube I can blast the pressure up to extreme levels and no worries about blow out or rupture! Get these if you're serious about touring and want reliability! 5 Stars all the way!
I've had these since I've been running the Continental Top Contact II tires. So far I've been pretty happy with them. I've had two tubes that exhibited a slow leak at the value. This valve appears to have a replaceable core, but if they are threaded loosely into the body, then they will leak, especially if you have to exert much force to unscrew the valve for inflation. A gentle tightening has done the trick for me.
For utilitarian bike riders, or those who will do anything to keep from getting flats, rolling around on balloons is always precarious.
The more rubber, the better - but Thorn-proof tubes are too thick to patch, the tubes with goop inside are tiresome, unpatchable and ultimately leaky, and normal tubes are too thin...in the interest of saving weight? A thin balloon?
...so the Continentals are my current best solution to the dilemma. The rubber is a little thicker.
When something better comes along, I'll get it.
I had four flats within two weeks against the inside of the rim with brand K. I ordered a couple of these Continental Tours and a couple of Michelin Airstops to see if it was the fault of my rimrim tape (I never could find any problem with the rim or tape) or if it was the fault of the tube. I put in the Continental and it has been over 30 days and 400 miles of riding and I haven't had a flat (so I haven't tried the Airstop yet). The overall quality of the butyl, the seams, and the valve look better than brand K also.
I like this tube and the price. It is high quality, thick tubing. I also like the steel nipple. But, the retaining nut is VERY brittle. And, there is no point in using the retaining nut on aero rims.
An unreliable tube is a royal pain in the rear. My hybrid bike came with CST tubes stock, and they sheared at the valve stem. I had already installed a set of new Continental tires that I was very satisfied with, so I though why not give Continental tubes a try. Right out of the box these showed quality. They were thicker than the CST/Specialized tubes, and the thickness more consistent. The steel valve stem with the locking nut (a rarity for Schraders) was a nice touch. So far, I have put about 600 miles on these tubes without any trouble. No pinholes, no seam tears, no valve stem leaks, etc. They also seem to hold air better, with only minor pumping every week to keep them around 55psi.
You really cannot go wrong with these tubes. The cost is similar to other brands, but the quality is excellent.