1: Fragility. They’re skinny and stick out farther. It’s easier to damage one. And once damaged, they make the tire difficult or impossible to fill, and they might leak all the air out as well.
2: Lack of Standardization. Everybody has Schrader valves. Cars, motorcycles, wheelbarrows, hand carts, tractors, airplanes, even oddball things like some pressurized air cans and inflatable rafts. Which means, for example, it’s easy to stop at a gas station that has free air and refill your bike tires there with no adapters needed. Pretty much every air pump and air compressor you’ll ever come across already has the ability to fill Schrader valves. There’s no reason bicycles should have a special valve that’s not compatible with all of the other things out there.
My main gripes are:
1: Fragility. They’re skinny and stick out farther. It’s easier to damage one. And once damaged, they make the tire difficult or impossible to fill, and they might leak all the air out as well.
2: Lack of Standardization. Everybody has Schrader valves. Cars, motorcycles, wheelbarrows, hand carts, tractors, airplanes, even oddball things like some pressurized air cans and inflatable rafts. Which means, for example, it’s easy to stop at a gas station that has free air and refill your bike tires there with no adapters needed. Pretty much every air pump and air compressor you’ll ever come across already has the ability to fill Schrader valves. There’s no reason bicycles should have a special valve that’s not compatible with all of the other things out there.
Presta valves also don’t allow airflow need to seat tubeless tires.
For point 1, I’ve only had a Presta fail when the rim hole had a burr. Mostly I rode in snow and ice though and not forest trail.
For pointr 2, the tiny adapter can be left on your presta, or carried in your patch kit.
That just sounds like Schrader with extra steps…
Narrow rim with small hole is stronger, really the only reason for presta, other than you can partially fill a presta tube with your mouth
To fall off.
I have never had one fall off. But I do have a spare in my patch kit as a what if scenario