Tubed tubeless tyre

[Brettaboy]

Morning All
Last year I had the tyres on my Thruxton R replaced. This bike uses tubeless tyres with tubes due to having spoked wheels.
The rear had a new tyre and tube and showed a leak of about 2psi each week, the dealer replaced the inner and kept the old one on his bench. The front pair are fine.
The rear tyre still loses about 2psi each week and the inner retained by the dealer didn't lose any pressure - weird!
Has anybody any thoughts as to what might be going on?

[AJHDingo]

I have no experience of tubes in tubeless so this a thought. Is it possible the seal between the tubeless tyre and the wheel is pretty good and the tube is expanding inside up to pressure but with still free space inside the tubeless. The airgap between the tube and the tubeless gradually leaks and the tube expands lowering the pressure. if this is the case it should eventually stop when the tube fully fills the tyre?

[mrtomsv]

CO2 molecules pass through the rubber of inner tubes relatively quickly. Whenever I replace a tube it’s noticeable that the pressure drops fairly quickly as you describe, but over time every time you top the pressure up, the concentration of CO2 in the tube reduces and so too does the pressure loss until it becomes negligible over a few weeks.

Don’t know why the dealer claims no pressure in old tube. Would take with a pinch of salt.

[tinhead]

Doubt they had the tube inflated to full pressure on the bench as they'll blow up like a balloon when not contained by the tyre, also not a great test as its not subjected to the same heat & movement it would be on the bike.

I converted my thruxton R to tubeless over 2 yrs ago, best decision ever, tubes on road bikes are a potentially dangerous throwback, I suffered a puncture and very rapid deflation before going tubeless, all from a small nail that would have caused a slow puncture at worst and probably not even that in a tubeless tyre.
Apart from the fact they'll leave you stranded as they're virtually impossible to repair at the roadside.

Sealed mine with 3M extreme sealing tape with extra strong gorilla tape on top for added protection, done over 10k miles since with no problems or
pressure loss.





something to consider, wish I hadn't waited until my puncture

[fred bloggs]

tinhead said:

Doubt they had the tube inflated to full pressure on the bench as they'll blow up like a balloon when not contained by the tyre, also not a great test as its not subjected to the same heat & movement it would be on the bike.

I converted my thruxton R to tubeless over 2 yrs ago, best decision ever, tubes on road bikes are a potentially dangerous throwback, I suffered a puncture and very rapid deflation before going tubeless, all from a small nail that would have caused a slow puncture at worst and probably not even that in a tubeless tyre.
Apart from the fact they'll leave you stranded as they're virtually impossible to repair at the roadside.

Sealed mine with 3M extreme sealing tape with extra strong gorilla tape on top for added protection, done over 10k miles since with no problems or
pressure loss.

something to consider, wish I hadn't waited until my puncture

Agree. Tubes are for pushbikes. The kits above work well . Tubes always leak slowly. Fact of life.

[ssray]

Tubeless tyres are left rougher inside

[catso]

mrtomsv said:

CO2 molecules pass through the rubber of inner tubes relatively quickly.

My old Guzzi has innertubes but is fitted with tubeless tyres (not sure you can even get purely 'tubed' tyres that are suitable/any good for a fast(ish) road bike?) and I have noticed that, despite no punctures/leaks the tyres do lose pressure much quicker than my tubeless bikes - the above statement from mrtomsv would explain this and, I guess makes sense due to the thinness of a tube compared to a tyre.