I was skeptical about changing the presta valve. It has worked since the 1890's without much change. I bought the cores to prevent clogging with tubeless sealant. So far the valves have worked flawlessly. No sealant clogs, no leaks. The pump head worked better than I had expected too. It just clicks on and I dont have to toggle anything and it gets a tight seal. I've been using these for about three months and they have worked like new every time I pump up my tires. I plan on getting these cores for all of my wheels. Luckily they are not too expensive.
