I suspect that the used bike I want to buy might have a tubeless tires, but one is flat. Is there any external feature to look at that would allow easily to tell this for sure?

I have no experience with tubeless tires and would not know how to replace it.

  • 6
    Um... ask the seller? And if they don't know, walk away because the bike is stolen. If they say it is tubeless and you like everything else about the bike, why not just learn how to use tubeless? It can't be that hard. Commented Nov 14, 2018 at 9:59
  • It is not properly written in the description from the shop.
    – nightrider
    Commented Nov 14, 2018 at 13:08
  • I somehow feel that the answer of "poke it with a knife and see what happens" might not be the answer you're looking for.... though I can promise you it's got a very high accuracy
    – UKMonkey
    Commented Nov 14, 2018 at 14:16
  • 3
    @h22 I'm surprised that a shop would sell a bike with a flat tire. Commented Nov 14, 2018 at 15:36
  • 4
    @h22 So... ask the seller? Email or phone them and ask them the specific thing you want to know about the thing they're selling. Commented Nov 14, 2018 at 15:45

4 Answers 4


While your question of identifying a tubeless tyre has been answered, I think that might not actually be what you have to worry about. A bike might come with tubeless tyres, but that doesn't mean that they're set up tubeless. The tyres might still have a tube in them, so your concern should be identifying whether there's a tube inside or not. The easiest way to do that is to look at the valve stem, because a tubeless valve will almost always be secured with a substantial lockring, whereas a tube with a presta valve might have a little silver lockring or usually nothing at all. Any wheel with a Schrader valve is almost certain to have a tube in it as tubeless Schrader setups are extremely rare. This isn't foolproof, because some people will put a big lockring on a tube and some might put a small one on a tubeless valve, but I'm confident that this will be accurate over 95% of the time.

Schrader valve:

Schrader valve

Presta valve (tube):

Presta valve (tube):

Tubeless presta valve:

Tubeless presta valve

  • 1
    Very good detective work on telling whether there is a tube inside or not! I would not imagine it was possible to do it by just looking at the valve. Welcome to the site, byt the way. Commented Nov 14, 2018 at 10:32
  • 3
    It's a tubeless tire setup without the tire. The valve is attached to the rim (where else it could go?).
    – anatolyg
    Commented Nov 14, 2018 at 12:28
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    A Presta valve without a removable core points at a tube. With tubeless the core needs to be removed to fill in the sealant. The opposite is NOT true however.
    – Carel
    Commented Nov 14, 2018 at 13:28
  • 3
    I've installed hundreds of tubeless tires and I've never used a special lockring. I've only ever used a normal one and just gotten it as tight as possible using my fingers. I've known people to either use a special lockring or use pliers to tighten down the ring, but if you ever need to put a tube in the tire while on a ride, you won't be able to do that if you need pliers or a tool to get the old valve out. That's why I've only ever hand-tightened them. The sealant will seal up and small gap caused by this method. Commented Nov 14, 2018 at 15:35
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    The tyre may have been tubeless with sealant in the past, but then had a tube put in it for convenience after going flat. That would explain the remnants of sealant. I currently have a tube in the rear tyre on my road bike because of a puncture that I fixed while out riding. The hole was too big for sealant, but not an issue for a tube. Once I've worn out the tyre, I'll get a tubeless replacement and set it up with sealant again. Commented Nov 18, 2018 at 6:56

Look at the tire sidewall for model/name, tubeless tires usually have TL, UST, TR or Tubeless in it; some tires don't (like Schwalbe Pro One), so google the model and see if it's tubeless or not. Keep in mind that some MTB tires can be setup tubeless regardless of what manufacturer claims, in this case you can unseat some tire bead and check if there's tube or sealant residue inside.


For a tubeless setup you need three things: the right rim, the right tire, the right valve-stem. Carbon side up shows how to identify the valve stem, and the tire and rim should be marked, but you need to check all three, because having tires and rims rated for tubeless may be used with a tube (I do this all the time on riding lawn mowers because their rims suck and leak even though designed for tubeless operation.)

However in your case there is an easy check since there is a flat tire. First look at the valve stem. If it is a presta use your fingers to loosen the stem nut (skip if it is too tight to loosen by hand), then wiggle the tire relative to the rim while watching the valve stem. if wiggling the tire moves the valve stem you have a tube if you feel the tube stretching against the valve stem, you have a tube, otherwise either you have a tubeless setup or a burst tube.


I'm wondering if you could weigh it. Look up the weights of the wheel and tire and subtract them from the total weight. If the difference is more than a few ounces to account for the stem and sealant it probably has a tube, right? Just throwing it out there since I have to figure out the same thing on a used bike with the right stems but inconclusive on tubeless. I don't really want to break the seal to find out.

  • Hi, welcome to bicycles. This seems finicky and error-prone. You'd need to get really good weight measurement, know exactly how much the amount of sealant in a tyre would weigh (and it would have to differ perceptibly from a tube's weight) and how would you account for wear on the tyre?
    – DavidW
    Commented Aug 15, 2023 at 14:29
  • welcome to the site - this is a reasonable idea, but tyre weights alone can vary by up to 10% from published specs so there's too much combined variability.
    – Criggie
    Commented Aug 15, 2023 at 19:33

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