I wonder if this wi...
 

I wonder if this will catch on?

 Bazz
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Racing on a tubeless set up with an emergency back up

https://www.cyclingnews.com/news/why-did-keegan-swensons-wheels-have-two-valves-each-at-unbound-gravel/


 
Posted : 01/06/2025 9:54 am
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It sort of makes sense, except of course if there’s some debris or Thorns or something lodged in the wall of your tyre (that you’ve not spotted), you’ll potentially inflate the backup tube and immediately puncture it… 

Also doesn’t this go against all the “rotating mass” wisdom by saddling you with both sealant and tubes in your wheels? I assume they’re using TPU to minimise the weight? 


 
Posted : 01/06/2025 10:35 am
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Imagine if this was spotted on April Fools Day....


 
Posted : 01/06/2025 2:22 pm
 Aidy
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Posted by: cookeaa

It sort of makes sense, except of course if there’s some debris or Thorns or something lodged in the wall of your tyre (that you’ve not spotted), you’ll potentially inflate the backup tube and immediately puncture it… 

I guess you wouldn't be in a worse situation though... like, best case it works, worst case you're still popping the tyre off and sticking a tube in.

I'm still not sold though, if you actually flat the tyre, you've got a non-zero chance of destroying the uninflated tube rolling to a stop.


 
Posted : 01/06/2025 2:44 pm
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So you have the weight of sealant AND an inner tube. 


 
Posted : 01/06/2025 3:19 pm
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I suspect it will be something like the Tubeliss setup for motorbikes. Where an inner tube is used in the wheel well to hold the outer tyre in place and act as a cushcore at teh same time.


 
Posted : 01/06/2025 8:47 pm
 Aidy
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Posted by: Brainflex

I suspect it will be something like the Tubeliss setup for motorbikes. Where an inner tube is used in the wheel well to hold the outer tyre in place and act as a cushcore at teh same time.

They say in the article that that's not what it is - it's there as an emergency inner tube in case of flats.

The thing you're describing does exist, though - https://bikerumor.com/odyssey-optis-pneumatic-tubeless-tire-insert/


 
Posted : 01/06/2025 9:04 pm
Brainflex reacted
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There’s also a Schwalbe one

https://www.schwalbe.com/en/blog/news/innovation/procore/


 
Posted : 01/06/2025 9:09 pm
 K
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Such a good hack that they didn't actually use it when he punctured but instead swapped wheels. Could have just used a heavier tyre in the first place. 


 
Posted : 02/06/2025 6:27 am
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Who remembers "Pro-core" ?

That was basically an inflated Road tyre inside of a tubeless MTB tyre to act a bit like a a Run Flat. A fair bit firmer than a foam insert... 

It does feel like several people are constantly reinventing the same few solutions to flat tyres... 


 
Posted : 02/06/2025 12:46 pm
 Aidy
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It was two posts up


 
Posted : 02/06/2025 12:56 pm
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You're all reading too much into it, it's just logo/valve placement OCD. Two logo's on the tyre, why not have two valves to line them up with? 🤣 


 
Posted : 02/06/2025 1:06 pm
zerocool reacted
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I suppose you could solve the problem of it pinch flatting before it had even been used with some sort of weak ties or glue that held it in place rolled up in the well of the rim? Just a bit of cotton thread around the circumference would probably suffice, it'd roll off the tube as it inflated? 

Such a good hack that they didn't actually use it when he punctured but instead swapped wheels. Could have just used a heavier tyre in the first place. 

It does feel like several people are constantly reinventing the same few solutions to flat tyres... 

+1

I tried inserts on the gravel bike, and they did sort-of work.  But I agree, there's a lot of effort, expense, and lost performance* going into avoiding what is a relatively simple fix of shove an anchovy/dart/plug in, pump with some air and get going again. 

*because most of these systems are significantly heavier than most people would baulk at adding to the weight of their £1000 carbon wheels.

 


 
Posted : 02/06/2025 2:22 pm
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The main issue I can see with this is just that if you flat, you're fairly likely to pinch the tube at the same time, it'll be vulneraable to getting caught between the rim and the ground. 

Procore was an interesting idea but pretty complicated and not cheap, and then they had some very public failures out on the EWS circuit (and because they made the procore bright blue, it was really easy to see when it was hanging out the side of someone's wheel). And then simple foam turned out to work pretty well with way less hassle. 

Posted by: K

Such a good hack that they didn't actually use it when he punctured but instead swapped wheels. Could have just used a heavier tyre in the first place.

Doesn't mean there was no circumstance where it'd have been useful, though. If I understand correctly, he used a plug initially, which would be better than switching to the tube as it gives you back the initial tubelessness etc (and also still keeps the tube in reserve, and avoids the risk that the tube had flatted in the incident). It'd always make sense to do that first. And then they swapped wheels later because they didn't trust the plug repair, and because he was the team leader and they wanted him to have hte most reliable bike.

But I think the teammate carried on with the flatted wheel? I've not seen any comment on what they did with that wheel- as far I can tell he completed the race on that wheel and the plug held up?

 


 
Posted : 02/06/2025 4:53 pm