H: Hubs, Wheels and Tyres Quality of Inner Tubes

Matty

Matty

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Hi
Much Time has passed since my last contribution about tyre pressure loss but even at 87 I have had another thought on the matter.
Spoked rims use a sealing /protection band to stop the spokes puncturing the inner tube.
This could act as a seal over the spokes and trap some air for some time between the tube/tyre/rim when a new tyre is inflated and give a false reading until the trapped air leaks past the protection band, through the spoke holes.
The protection band could easily seal in the trapped air for several days/weeks and result in an apparent slow deflation.
I have noticed that after a few days the pressure loss gets much less - and in fact my Comet's tyres have not needed to be pumped up for about a year now that things have settled down.
While having the problem and having bought new tubes, valve seals etc with no improvement over a few months, I have now concluded that the pressure loss must be due to air trapped between the tube and tyre and leaking slowly away.
 
Colin

Colin

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Matty. Thanks for the above, glad to see we octogenarians are still usuing our grey matter, not to mention our bikes!
However I think it likely that you have rubber innertubes, and real rubber ones do leak air a little all the time. Inner tubes made of Butyl and the like do not do this BUT I would always go for rubber as Butyl and like seem to deflate almost instantly when punctured, as they tend to split from a puncture point. Whereas rubber will hole from a puncture, usually/mainly without splitting, and thus deflate more slowly.
MORE SLOWLY deflating at 60mph is very valuable, as it will give you time to stop, before you lose control
I suspect pressure loss gets less after a few days simply because the pressure available to deflate is less.
Check to see if you have got REAL rubber tubes and not something synthetic.
What ever else you do keep on riding, and keep your wheels between the ditches
 
Speedtwin

Speedtwin

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Michelin tubes are probably the best tubes out there good quality material, the MX heavy version is not suitable for road bikes.
The heavy duty MX are for low pressure use on trials and motocross machines.
My tyre man will only fit the Michelin tubes which are designed for road use, he reckons the others mostly synthetic mix are no use I brought some Redwing HD ones down to him when last fitting tyres to my Rapide he threw them in the bin and fitted the Michelin tubes.
He has forgotten more than I will ever know about tyres.
My tyres stay hard another consideration is when leaving your cycle standing do not leave it in contact with a concrete floor insulate the contact patch by standing on rubber mats.
Concrete floors suck the life out of your tyres and tubes.
Al
 
Alyson

Alyson

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First, I'd check to make sure the valve in the stem is tight, and, make sure you always put back on the cap. Another thing, Nitrogen in the
tire/tyre will hold up much longer than air. It's a better way to maintain the tire pressure. Also less expansion and contraction than regular
air. I believe that's why airplanes use nitrogen in their tires. Just my 2 cents.
 
vibrac

vibrac

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My modern ride is a tubeless GS BMW with tyre pressure sensors. For 10 odd years I have had to pump up the rear tyre weekly nobody can fix it I have been through a few tyres and valves and to have the damm thing telling you you are underinflated is a pain especially as the electronics only kicks in to tell you after half a mile of riding! So the Vincent is a joy for pressures in comparison. Incidentally I tried MX thick tubes in my trail bike in the MCC Edinburgh long distance trial, only time I ever had a blow out,,,
 
Texas John

Texas John

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I bought a tube and tyre from DennisKirk.com in late 2021. It was one of their butyl tubes which they claim will hold air like tubes of old. I am now a believer! Mounted tire in Dec '21. As a test, I started with 42 PSI (high - working on bike, not riding it yet) and in Jan '23 (13 months later) it was at 23, so a loss of 19 PSI in 13 months, or about 1.5 PSI per month. That's much better than the 5-10 PSI seen with every other recent tube I have tried.
 
Texas John

Texas John

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