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I noticed my back tyre has hollow knobs and I can't remember ever seeing this before. Some of the knobs have turned out to be hollow inside. I know YGWYPF, my questions are:

  1. Is it normal? I got no meaningful results with google.
  2. Is it desirable on a budget (even cheapskate really) tyre? It wouldn't surprise me on a £££ model, but in this case my guess would be that it would not meet the balance between extra cost of manufacturing complexities vs the savings on raw materials.
  3. Shouldn't the label say the knobs are hollow? My loose thoughts would be that this has a bearing on a user's ability to assess things like performance and remaining life? Even if it's the subconscious visual assessment of these? I bought this in the UK but it's a global brand (and so is probably the model).

I'm aware many on here would argue this tyre is way overdue for replacement, this is not what the question is.

Edit: Clarification in response to some early comments.

  • I can't tell for sure if this is a manufacturing defect, it might be, but I think this is part of my question really.
  • The holes do not seem to go through the casing to the tube inside. The best way I can describe it is that it seems like they are hollow blocks/knobs glued onto a slick tyre. It also seems that the hollow space inside the hole is bigger that the opening that has been created.
  • I estimate I've ridden 100 to 1000 km on this tyre, 95% tarmac (from dry to heavy rain), 5% well compacted gravel path, very little harsh braking. Estimates are very rough because I don't use any tracking and my cycling comes in irregular spells of commuting.
  • They do indeed seem irregular. To me, this could equally indicate "unintended error in manufacturing" or "intended by design but poorly executed". The photos are a decent indication of the number and spread/distribution around the whole tyre. I'm fairly sure I didn't ride over enough broken glass (or similar) for that to be the main cause.

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    I think the real question is if this is a manufacturing defect and if you have a right to a warranty replacement. To me it certainly looks as if they unintentionally trapped air/gas inside the knobs during the manufacturing process.
    – Michael
    May 11, 2020 at 12:47
  • They seem irregular. Are you sure you didn't ride over some broken glass that has broken the surface/degraded the rubber?
    – spikey_richie
    May 11, 2020 at 14:10
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    The tire is worn well past its designed useable limit.
    – mattnz
    May 11, 2020 at 19:56
  • @mattnz Concur - 1000 km is a bit poor for any tyre. Pateksan should replace it when it starts to puncture more or when grip is insufficient. Perhaps choose another brand of tyre next time.
    – Criggie ♦
    May 11, 2020 at 20:20
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    1000 km from a knobbly mud tire on paved roads is actually quite a lot. The rubber compund is designed to stick to slippery roots, not last forever (can;t have both). OP would be much better off buying a much less agressive tire more suited to paved roads.
    – mattnz
    May 11, 2020 at 21:56

1 Answer 1

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I don't think the tread blocks are 'hollow' exactly.

Tires are made up of layers of different formulas of rubber. I think you have worn though the outer layer and a little chip of rubber has flaked out of the center of some of the the blocks. Now you can see that the next layer down has de-laminated from the outer a little, so it looks like there is a void there.

If the blocks are hollow, the void is only right at the bottom of the block, and would only be exposed if the tire is very well worn, as yours is.

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  • I think I fully understand what you're suggesting up to "some of the the blocks". And then I totally don't get the last sentence. To me it seems that the "next layer down" is the main "body" of the tyre (shown as "tread" in diagram here: road.cc/content/feature/…); and that "body" seems intact as far as I can tell. In other words, to me your answer makes perfect sense if I take it without that last sentence. Are you by any chance aware of a diagram which shows the layers so that we could refer to them clearly?
    – pateksan
    May 11, 2020 at 17:30
  • Ouch, you edited your answer (added the last paragraph) as I typed my comment. I'm sorry if I made it confusing for everyone.
    – pateksan
    May 11, 2020 at 17:31

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