News

May 28, 2023

ASK MBA: DO PRESTA VALVE CAPS DO ANYTHING?

Q: Hi, MBA team, I’ve been riding bikes for years now and have never really given much thought to how important or unimportant valve caps are. Is there a particular reason I should stress about

Q: Hi, MBA team, I’ve been riding bikes for years now and have never really given much thought to how important or unimportant valve caps are. Is there a particular reason I should stress about keeping them around or is there not really a reason for it?

Caleb Gregory

Durango, CO

A: That’s an excellent question that has a few different answers. It really comes down to what type of valve you have on your bike. Most mountain bikes within a certain price range come with Presta valves that close and seal themselves without the need for an additional seal. Their caps are only there to keep the sharp valve tip from puncturing the tube in the box. Schrader valves, specifically ones with a lot of pressure behind them, actually rely on those caps to complete the seal and make it airtight—that’s why they have a rubber seal inside the cap where it meets the outer edge of the valve. They also keep dirt out of the spring loaded mechanism’s sealing surfaces. This is important to remember when adjusting the air in your suspension because they predominantly use Schrader valves. There are also the Reserve Fillmore Valves, which are claimed to be a major upgrade on the Presta valve design. They actually use the cap to pull on the core to complete the air seal.

Though valve caps aren’t necessary for Presta valves, that doesn’t mean they can’t be useful, plus some think they look kind of strange without a cap. That’s why so many companies are making valve caps that double as a tool. Typically, this tool is designed to remove the valve core if something goes wrong on the trail, but we’ve also seen ones with little LED lights that light up when your pressure gets too low. These come in all sorts of different colors and often come with some of the more expensive tubeless valve sets, like the Lezyne CNC TLR valve set whose caps both tighten the valve stems on the wheels and unscrew the valve cores. You can also get caps with valve core removers as a pair on their own if you’d like. Looking to upgrade your valve stems? Check out our ten favorites here.