Robot’s Useless Reviews – Valve Stem Caps

When I was a young robot and not yet programmed for cycling wisdom, a local pro approached me, a new friend of mine. She leaned down and removed the valve stem cap from my front wheel. Then she threw it over my shoulder into a nearby garbage can. “You don’t need that,” she said. “You never need that,” and she smiled a smile that was both friendly and pitying.

Since then I have held the view that those small plastic caps are, indeed, pointless.

Oh, there is an argument to be made that they protect your valve from malevolent forces, but I have yet to see a force more malevolent than the rider him/herself who might cause damage to an innocent valve. I myself have sheared off the top pin by overzealously removing the pump head before adequately releasing its purchase from the stem. And I have seen corrosion do terrible things as well, the buildup of road salt and grime destroying the fragile valve, but in the former case, the cap does no good, because the rider has already removed it, and in the latter case, the rider gets exactly what s/he deserves for not cleaning their bicycle adequately.

Are we a bunch of animals? Don’t answer that. It was rhetorical.

And so we return to the premise that the valve stem cap is a waste of time and material.

For many years I was involved with the sale and delivery of very high-end, custom bicycles. All those bikes left the shop with valve stem caps in place, for it was not my money that purchased the tubes, and so not my place to decide for the rider whether a cap was a jaunty accent or handful of useless grams.

Wind tunnel testing concludes that the valve is more aerodynamic without the cap, too. AND, I have just slapped myself for writing that sentence.

As a fairly predictable aside, I’d like to just say that I have heard valve stems referred to as ‘nipples,’ as in “Make sure the nipples line up with the logos on the tires.” Without meaning to be prudish, that’s just a poor use of the word “nipple,” even if it’s mechanically correct. And while I confess I DO always align my valve stems with my tire logos, it’s one of cycling’s many rules that I find kinda dumb. I know where the stupid valves are, because there are valves there, and if we’re only doing it for the aesthetic symmetry, well, I just can’t even.

Even though I can and do. Because I’m a sheep.

Also, let’s not spend all our time up the business end of the nipples. There’s a small, round, knurled nut that secures the valve in place on the rim. How am I supposed to feel about that? On the one hand, maybe the nut keeps the valve from rattling against the hole in the rim and/or the tube from working back and forth inside the tire and shearing the valve off completely. On the other hand, how many of these can I drop behind my work bench where evidently they fall down a wormhole into a parallel dimension that is home to small hardware of every stripe? The answer: All of them.

And why are those things knurled? How much does nut knurling add to the cost of the nut/valve/tube module? Is there someone, somewhere whose whole job is nut knurling? The mind boggles.

But let’s get back to our nipple covers, our velo-pasties, if you will.

Did you know that the accumulated weight of all the world’s useless valve stem caps is equal to the weight of all the blue whales still in the wild? That’s a lie, but unlike valve stem caps, the whales are worth saving.

This review goes on and on, and we haven’t even mentioned anodized aluminum valve stem caps, color coded to match hubs or rims or bar tape, a level of matchy-matchy preciousness that bears vivid testimony to the vast excess of time humanity evidently has on its hands. I’m embarrassed to have brought it up.

Look, here’s the bottom line. If, as you read this, you think to yourself, “Hey, I use those caps!” Well, that’s good actually. It means a few less plastic bits leaching their chemical poison into the ground water, and it means you’ve got your nipples covered, which in this day and age, is never a bad idea.


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Join the conversation
  1. Dad Cat says

    Hey, I use those caps!
    Out on a gravel road, I feel like they might just maybe protect the stem from a flying chunk of gravel. One in a million chance? Maybe. But it doesn’t hurt anything. And if it makes a hardcore roadie smirk at me, well… I’m already being smirked at by them for so many other reasons that it just doesn’t matter.

  2. TominAlbany says

    I find the caps on my garage floor mostly. And the knurled nuts I find everywhere. I’m sure there are some along the roadways as well, though, that was due to carelessness, which may or may not be worse than intent.

    As for lining up the tire logo with the nipples, that’s just good t-shirt etiquette.

  3. Austin says

    I usually get rid of the plastic caps because they’re just another little piece to keep track of whenever pumping. With that said, my mtb tubeless stems came with a cap that doubles as a valve-core-remover-thingy and I like that. So it stays. Some new tubeless stems for my gravel bike came with metal caps that are a pretty color. So they also stay until I lose track of them one day when pumping up the tires.

    I’ve found myself caring more about the logo/valve stem alignment that I forget to check which direction the tire should rotate until after I’m done. Not super proud of that. One is definitely more functional than the other.

    1. Emlyn Lewis says

      Yeah. Exactly. I line up the stem and logo and forget about tire direction all the time. Really, I don’t do anything to my bike unless I do it twice.

  4. alanm9 says

    I keep a few caps on the workbench for re-folding tubes that I just patched so the valve won’t wear a hole in the tube or anything else. Otherwise caps and nuts go in recycling. Which is a whole new thought that I’m letting go. My LBS owner always installs caps after he works on my bikes but never the nuts. Wonder why?

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