Tubeless Valve Assembly by Specialized

In this article, we’ll be discussing a Tubeless Valve Assembly by Specialized, US publication 20210023985. The publication date is Jan. 28th, 2021 and the filing date is Oct. 15th, 2020. This patent is a continuation of granted patent No. 10,807,424 filed on Jan. 5th, 2018.

The images in this patent show a road bike, but there’s no it can’t be used on any bike with a tubeless system. I have not seen this idea in the wild. If you have, please let me know. I’ve already missed one Specialized patent, so I could definitely miss another one.

This is a short patent, so it’s a short article.

Brief Summary (tl;dr)

No summary. This one is short enough.


In most bikes, that we buy from the shop floor, the tires will have a tube in them. The tube is there to keep the tire inflated and support the weight of the rider. Tubeless tire systems are a wheel and tire that do not use a tube to retain air pressure and keep the tire inflated. Instead, there is a stem that is airtight, and the tire is filled with latex to seal any small holes that may come from riding or manufacturing. The tire can then be filled with air without the use of a tube, like your car.

The advantages of a tubeless system are felt instantaneously. Lower tire pressure is the most important feature of this system. Low pressure = more grip (to an extent), and you can save a few grams. If you still have tubes in your bike, get those things out of there. It’s a cheap upgrade. There are tons of articles on the internet explaining tubeless.


I know this is going to get a lot of people going… proprietary. Though everything I write about is proprietary, that’s kind of how patents work.

Specialized are introducing a stem system that integrates into the rim itself. The rim has a threaded plate that a threaded stem screws into. And that’s it. Pretty simple.

Intended novelty

I’m going to state the novelty for the two patents related to this idea.

The intended novelty of 10,807,424 is the threaded plate in the rim and a threaded stem, where the stem is secured at both ends of the rim. This one is already granted.

The intended novelty of this one, 20210023985, is the exact same idea, but with a quarter turn, cam-type stem. This one is not granted yet.


Specialized don’t really have a problem statement in this, or why they’re doing it. I’ll assume it’s because they have too many engineers, too much money, and are doing this just because they can. Ultra-refinement.

I can say that I don’t like installing a DH tire and the bead getting caught on the inside of the stem, but it’s not a huge deal. Maybe they just want a super clean look because this looks pretty slick, or maybe this will be a benefit to a road wheel scenario.


The stem is threaded and is screwed into the inside of the wheel itself. There are a few examples in this document. The first example is shown in Figs 3 and 4. There is a threaded plate that is attached to the inside of the rim via adhesive or fasteners:

The threaded [plate] 58 is preferably secured to the rest of the outer wall 48, such as with adhesive or fasteners.

The threaded stem screws into the threaded plate, and a rubber ring 82 is slid onto the stem and secured in place by recess 80. When the stem is threaded into place, the stem goes through both sides of the wheel and the ring keeps air from escaping from the spoke-side of the wheel.

4/14 edit: As Maciek noted in comments, the 80/82 don’t hold air. Bad research by me.

Spesh say: the [recess] 80 and [rubber ring] 82 are aligned with the radially inner wall 46 of the rim 42 such that the [rubber ring] 82 is positioned in the inner opening 50, which provides a cushioned connection between the valve stem 66 and the inner wall 46 of the rim 42. This cushioned connection reduces audible rattling that might occur as a result of intermittent contact between the valve stem 66 and the inner wall 46 of the rim 42.

The next example is exactly the same, except the threaded plate is integrated into the wheel itself, shown in Fig 5.

Lastly, the example from this specific patent performs the same function but with what Specialized are calling a quarter-turn, cam-style receptacle. In the end, it’s the same thing with a quarter turn instead of threads. This is shown in Figs. 6, 7, and 8.


Again, proprietary. You won’t have the freedom of buying your preferred stems. Or if one breaks, you can’t go to your closest LBS to pick up a new Stans. It’s not a huge issue, but could be an annoyance.

But seems like a cool little idea and may be good for some scenarios. Progress is progress, even if it appears unnecessary.

4 thoughts

  1. Possible explanation for “why”: Many people crank down the valve nut on tubeless valves, often with pliers. The inside surface of the rim may not be strong enough for this compression load, especially on a road rim. This allows for either a thinner rim or eliminates the need for localized reinforcement.

  2. Thank you for your great work. I think I can list a few additional novelties of this one:

    1. removes the valve nut from view – important (all is relative) for aero and esthetics – a market differentiator
    2. the rubber gasket in the middle (80/82) does not seem to be an air seal – this would imply the whole rim cavity would be pressurized and it does not make sense. It rather stops valve from rattling against rim – this is why it is called “bumper” in the claim – a typical problem in high profile rims with classic tubes where valve nuts are not used

    Quarter-turn vs. threaded may be for different applications depending on intended tire pressure i.e. threaded for road and q-turn for offroad.

    A side observation – these kind of large openings are typical for carbon rims and are used to remove plastic bags used for pressurizing the carbon layups from inside the rim cavity when “baking” components in production. They are sometimes patched with carbon inserts in subsequent manufacturing process or left open (e.g. some Bontrager rims). This patent is taking advantage of such opening – a cost saving?

    1. Great observations. Appearance is huge to biking, so you may be on to something there. And you’re right about the 80/82. I fixed the article. Thanks for paying attention and correcting me.

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