I matched A1 air stop tubes with Michelin pro 4 tires witch worked out really well, these tubes a good buy for the money seem to hold air longer and have a nice smooth valve I'm satisfied and feel others will be too.
There's nothing I don't like about A1 Airstops. They have the right balance of lightness and puncture resistance. The valves are smooth so they don't chew up the chuck on my air pump. The 40mm stem length is perfect for HED Ardennes and other low-profile wheels.
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.
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.
Size and Weight Michelin states on the box 700x1823. This site says 1825. On modern wide rims many 23mm tires actually measure 25mm. For example, Conti GP4000S II 23mm tires measure 25mm wide on my rims. I find these tubes still work fine, probably because they are average weight and a bit thicker than the lightweight Michelin AirCOMP. My 40mm AirSTOP tubes weigh 95 grams each (my 40mm AirCOMP tubes weigh 75 grams each).
Smooth Valve I prefer smooth valves because the don't chew up my pump head internal seal. I just make sure I have at least 15mm of smooth stem sticking out above the rim but 20mm is probably better if you have a pump head that is old.
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.
On two occasions the valve core failed to close when the nut was locked down on brand new tubes and allowed the air to escape when inflated. There was no way to fix the failure. Totally useless tubes. Never again.