Tested: Reserve Fillmore Valves

On behalf of the world’s professional mountain-bike gear editors, I have a confession to make. There are certain products which, because of that very profession, some of us should probably be disqualified from reviewing. I’m talking about products that require months of uninterrupted use before they would ever start to show signs of failure or triumph. Most full-time testers can rarely stay exclusive to just one bike for more than six weeks. Sure, we usually try and ride our personal bikes pretty regularly, which constantly serve as test mules for at least three components.  But still, our bikes are splitting time with the bikes we’re regularly reviewing. 

So, when the supposedly clog-proof Reserve Fillmore valves arrived with just five weeks (actually a pretty generous lead time) to expose their flaws, I doubted I was the right guy for the job. I simply don’t have issues with tubeless valves clogging until either they’ve been through a couple cycles of Stan’s refreshing, or I’ve made enough poorly-positioned pressure checks to suck in enough sealant to stop them up. So, I did what any resourceful professional would do: I outsourced. I installed a set of Fillmore valves for a friend with a single bike and more regular riding habits than myself. And because Reserve sent me an extra set, I bolted a pair on my recently completed Dream Build and hoped for the worst so I’d have something to talk about today.

Then, fate smiled on us in a very 2021 way. The release of the Fillmore valves was delayed by an extra month. Both my buddy and I would have double the time to abuse them. And I’ve never been so excited about evaluating something this seemingly mundane. So, before we get to the results, what are the Reserve Fillmore valves?

In a sense, they are a reinvention of the presta valve with the goals of increasing air flow and preventing clogs. Traditional presta valves are designed around a wedge-shaped seal somewhere near their center. They do a fine job of letting air pass through when that seal is open, and not letting it through when it’s closed. But they weren’t designed for modern tubeless setups. The space between that seal and the valve body is incredibly narrow. This limits the speed and volume of air that can pass through when seating a tire, and can trap sealant as it inevitably escapes whenever we hook up a pump. This is why tubeless valves have removable cores. You can force more air in, and clean the core while it’s out. But over time, sealant can booger up where the valve enters the rim. It’s an infrequent issue, so we tend to just deal with it. There have been a few attempts at redesigning the presta valve, including hollow cores to allow air to pass through the center for more air flow. There have been little snorkels at the base to offset the opening from the inner surface of the rim as it gets constantly coated. But none make the fundamental changes that the Fillmore valve does.

Reserve has moved the seal from inside the valve to its very base. That’s allowed them to increase the diameter of the seal itself, making it far less sensitive. It’s like a little rubber-edged manhole cover that pops up whenever the valve core is depressed. This helps prevent clogs because, when that manhole cover opens, it opens far enough to break any sealant that may have built up around it, unlike a traditional valve where releasing it simply sucks more sealant towards the wedge-shaped core. The other benefit is how wide it opens the valve when it’s depressed. Reserve claims it allows three times the airflow of a traditional presta valve, making seating quicker and easier. But that increased flow also makes it possible to inject sealant without disassembling the valve. If you’re used to pulling out your core to squirt in a refresh, it’s not necessary with the Fillmore valves. The particles are small enough to make it past the inner workings of the Fillmore core, so all you need to do is pull off the cap and insert.

So, the cap. Yes, you do need to use the cap. In the Fillmore valve, the cap is what cinches the seal closed. Many of us have learned that presta valve caps are an unnecessary nuisance. It was something I had to adjust to, but the good news is, the valves do what they say.

After over two months, the Fillmore valves are working as clean and clear as they were the day they were first installed. As for the easier seating, though, neither of us had a problematic enough tire and rim combo that we couldn’t get a seat with a regular floor pump and little force. But that’s a four-for-four success rate, which I’d say is pretty good. And as for adding sealant, I was skeptical that there would be enough room for the particles to make it through the valve’s internal structure without bottlenecking at the entrance. It wasn’t as quick and effortless to inject as a traditional valve, but it gets the job done.

Though adding air through a Fillmore valve feels like I’m used to, letting air out is a little different. Air is released more rapidly and more forcefully with each tap. Reserve recommends simply loosening the valve cap instead of removing it entirely if you need to burp some air, which did the trick nicely.

To make it clear, though these are branded with Santa Cruz’s Reserve wheel name, they work on any rim with a 28mm depth or less. Some high-profile rims won’t make the cut, but even my ENVE M35s have a few millimeters to spare.

Now all this comes at a cost. $50 is likely more than you’ve ever spent on a set of tubeless valves. And honestly, if you generally aren’t dealing with clogs or poorly seating tires, there are no other quality of life improvements offered by the Fillmores that I could point to to sell you on them. But if you do, they’ll feel worth the investment next time you’re reaming out your old valves with a 2.5mm wrench. They will literally buy you time, at least until you too can ride a new bike every other month.

 Photos: Ryan Palmer