I only use smooth stem tubes on my bikes as they do not tear up the o-ring seal on my pump. Smooth stems are hard to find as most manufacturers insist on putting the unneeded threads on their tubes. However they are available here at a decent price. These are good quality tubes too. I have been using them for many years and have never had a flat as a result of a fault of the tube.
Michelin tubes seem to have a better quality stem than other brands. The presta valve just seems to have a more substantial feel to it than others. The tubes hold full pressure longer than others, not necessary to check pressure before every ride. Not sure if it is the quality of the rubber or just better construction. Before getting these tubes, I thought a tube is a tube, they all hold air, but apparently some do it better than others!
I'm lazy and don't like to pump up tires before every ride. Michelin Airstops loose pressure at a very low rate, so I inflate on Friday and ride all weekend secure in the knowledge that my tires are still in the set pressure range. I also love the smooth valve stems as they don't chew up the rubber seal on my track pump.
These tubes are good when they stay inflated. I have two, 700 x18-25 Presta 52mm fail because the stem will not lock closed. I would inflate them to 100 psi, close the nut, and air would leak from a brand new tube. A total waste. Because this is the second one, I will not purchase Airstops again. Neither Bikes Tires Direct nor Michelin had an explanation just news to them.
Good tube for 25 mm wide tires. I prefer the quality of Michelin tubes over others, less seam splitting and the slightly extra rubber helps resist those tiny pin pricks that can damage ultra light tubes. Probably want something lighter to stay competitive for racing. But if you don't like sitting on the side of the road fixing flats during training or recreational rides give these a try. I use tires weighing 215 to 240 gms on my road bike on city and country roads.
I keep several of these in my personal inventory because they hold air and I like the smooth stems. I need to check my tire pressure only once a week and then it is rare that they have lost more than 2 pounds. The smooth stems are kind to the grommet on my floor pump. I am sure these tubes are marginally thicker than most others, which makes them marginally heavier. It is worth it for tubes that do what tubes are supposed to do.
Even though the description does not say anything about the valve core, I bought these because someone complained that the cores came out when they used screw-on pumps. Unfortunately that information was incorrect. These do not have removable valve cores.
Maybe it was a bad batch, but just went through 4 of these with flats in all after 20-30 miles on each. Rim and tire fine, replaced with another brand that I got from the shop and have about 400 miles on them with no issues. Never getting these again. Again, reviews seem good so maybe it was just bad luck but it sucked because I was riding in remote places.
I've been using these for years now and they are high quality tubes that hold air reliably. I buy these specifically because I like the smooth presta valve vs. the threaded one.