Riddle me this: Ind...
 

Riddle me this: Indoor/trainer punctures

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Yes, exactly. More than three times now I have gone up to train and found that my bike has got a puncture on the trainer overnight. I've even had a slow puncture whilst training twice and it is frustrating as hell.

The tyre is a turbo-specific Conti. The latest inner tube was a new one, tyre pressure was easily in spec for the tyre and tube and had been fine last week for three sessions.  

It wasn't even cold over the weekend, so I can't imagine there was any realy thermal shrinking. What is going on? Is it a sign I should move to PU inner tubes, or just find the puncture, patch it and then fill the tube with a half syringe of sealant?


 
Posted : 02/12/2025 9:44 am
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Posted by: willard

Is it a sign I should move to PU inner tubes

No, it's a sign to buy some winter boots and gloves and get outside


 
Posted : 02/12/2025 9:54 am
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It’s a sign you should move to a direct drive smart trainer!

Have you taken the tube out to find the hole in it yet? That should give you an idea of the cause of the puncture - if no hole then you have a leak out of the valve. 

Are you using super thin tubes or anything?


 
Posted : 02/12/2025 10:04 am
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Have you made sure there's nothing in the tyre (either free floating or embedded) that's causing the puncture?

Rubbing a paper tissue around the inside of the tyre can often help to identify a foreign object - and is less likely to result in a cut than trying the same action with your finger.


 
Posted : 02/12/2025 10:17 am
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Posted by: scotroutes

Rubbing a paper tissue around the inside of the tyre can often help to identify a foreign object - and is less likely to result in a cut than trying the same action with your finger.

This is genius! I normally just accept I'm probably going to shred my finger a little

Thanks for the tip, should help save my tips!

 


 
Posted : 02/12/2025 12:11 pm
scotroutes reacted
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No, it's a sign to buy some winter boots and gloves and get outside

I know, but I live in Sweden and that's currently not a brilliant idea. Or at least, it's not fun and will become even less fun as winter comes in.


 
Posted : 02/12/2025 12:40 pm
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... or just find the puncture, patch it and then fill the tube with a half syringe of sealant?

Patches tend to fail due to heat on a turbo trainer in my experience. 


 
Posted : 02/12/2025 7:23 pm
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Have you talced the tube/inside of the tyre? My guess is that the tyre is slipping slightly on the rim and the tube is trying to move with it but because the valve is fixed it can't move so splits. I've had this before and most commonly there is a small hole around the valve, where it joins the tube.

Talcing the tube stops it sticking to the inside of the tyre , allow it to slip over rather than drag the tube.


 
Posted : 02/12/2025 8:38 pm
 mert
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Posted by: MoreCashThanDash
No, it's a sign to buy some winter boots and gloves and get outside
Yeah, quite tricky to "train" in any meaningful sense when it's 10 degrees below zero outside. I mean, it's certainly an adventure...

 


 
Posted : 02/12/2025 9:12 pm
willard reacted
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I had this a while back on my turbo trainer. After several attempts at fixing & trying to find the cause of the puncture (there was no obvious issue with the tyre or anything stuck in it) I just bought a new tyre & that cured it. 
It was very strange, as I couldn't find anything causing it to puncture.


 
Posted : 03/12/2025 8:38 am
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Huh, talcing... No, have not done that, but will give that a go this time. Same with the sharp object thing althoughI find it hard to believe given the tyre having never left the house.

I went by my local shop (big shout out to Velotek!) and asked them. Chap suggested heat was my enemy and suggested a slightly thicker inner tube (and not the shitty Biltema one that I had to use last time because it was all I had), so that's going to get installed tonight before the daily session.

I wonder if I have any talc...


 
Posted : 03/12/2025 8:50 am
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I would also have a good look at the rim tape.


 
Posted : 03/12/2025 9:13 am
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With roller-type trainers the pressure on the tyre is much higher/different shape to riding on the road. This can cause the tyre to deform more, generated heat as well as the tube to ‘squirm’ within the tyre. Sharp edges around the valve hole, hard edges of the rim tape as well as debris embedded in the tyre can abrade/ cause punctures.


 
Posted : 03/12/2025 9:45 am
willard reacted
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Right, changed the tub.

Old one had a puncture away from the valve and was quite aggressive, not a split though and I guess it was the cheap tube. No sharps in the tyre, rim tape feels and looks fine, could not find sharps on the rim.

The inside of the tyre has been talc'd and everything is back on the bike. Soon... Soon it is time to try it.


 
Posted : 03/12/2025 4:24 pm