Originally Posted by
Kjas64
Does anyone else dislike them? I drill them out immediately. I did a brand new bike for a neighbor. Just curious, if they're so fantastic why don't you see them in all products? Ever see a presta on a well air tank?. Wheels have actually gotten wider . To each their own. My 81 miyata 750sr low end bike came with them. Cheap bike with prestas. Trying to impress buyers. Then immediately break them. I'm a schrader guy. Lol
Your definition of “low end” is vastly different from mine. From what I’ve seen of the Miyata 750 SR, it wasn’t a “low end” bike. Maybe not the highest end but certainly not the lowest end bike Miyata made. And, in my experience, low end bikes didn’t come with Presta drilled wheels.
As for Presta valves, they are an amazing bit of engineering. A Schrader valve has to be held open to put air in it. If the seal of the chuck isn’t tight, any air escaping from the valve is air coming out of the tire. I’ve seen people who can’t get the chuck sealed on a Schrader valve completely flatten a tire while trying to put air in it. In my experience at my local co-op, the vast majority of people can’t use a Schrader chuck on a compressor properly.
The Presta valve is self sealing. The valve opens when there is pressure over the pressure inside the tube and it closes when the pressure inside the tube is higher than the pressure outside. If the chuck doesn’t seal on the valve, the air in the tire doesn’t leak out.