Bag o' wind.

How long do your tubed tyres go before they need a good blast of air? My Eldorado and Convert seem to need their tyres pumped up weekly. (I know it’s a weekly check but my car tyres can go a year without need for air) Why do tubes leak so badly?

Them’s not inner tubes, them’s semi-permeable membranes. The tubed tyres on the Convert only need a whiff of air every month or so because I let some out when the pressures are checked.

I don’t know about semi permeable? :astonished: Why should an inner tube leak air more than a tyre on a tubeless wheel?

Inner tubes shouldn’t “leak badly”, are valves tight?

Good question. Wouldn’t have thought weekly was right. Just checked the NTX which has been HS for 6 months and it’s barely down on pressure.
Does innertube rubber degrade with age? If so could that explain pressure loss?
Have seen tubes that leaked slightly at the valve to tube area. This was attributed to ‘creep’ and/or overtightening of the valve retaining nut.
As noted could be leaking valve could be a culprit.
Best of luck

How long have they been on? I have a bit of an issue with my front inner tube at the mo, both tyres were new + new tubes about a month ago or so, the front kept needing a bit of a top-up every few days but seems to have settled down now more or less, so I wonder if this is a case of trapped air between tyre and tube gradually escaping, and the inner tube ‘bedding in’. (?)

The rear, OTOH, has pretty much stayed put, BUT does have two opposing flats on the valve stem thread which makes it problematic getting a seal when I put my foot pump on. Very annoying!

I don’t know about semi permeable? :astonished: Why should an inner tube leak air more than a tyre on a tubeless wheel?

Sorry I seem to be repeating myself! :question:

It’s a reasonable question!

Hmmm The universal curse of the 'Spooky Wheels" Bellagio…Instant answer from PappaDoc ( DuVallier)…Head Tuner in Haiti…(No Ju Ju intended)…On the offending tyre, remove the dust cap off the valve for one week after you have pumped it up to your desired pressure or you will be carried off to Babylon by fierce demons.
…Now, take the pressure reading again and see if the air loss has reduced from previous readings, or spiders will emerge from all your bodily orifices…(Rather like Lunch time @ Westminster on Friday afternoon)…And you too are lunch add on for the sacrificial virgin!

…Hmmm, I’d risk one eye…heheheheÂ

Twit… :laughing:

:smiley: :unamused: :laughing:

I think that semi permeable is probably the answer. Inner tubes do seem to come in different grades of thickness, and some do seem to go down quicker than others. I think that is mostly down to permeability and not valve performance.

I had a front wheel blowout on the M6 at about 120mph 14 years ago.
The bloke who recovered me and fitted a fresh tube said that cheap Taiwanese tubes either stay up or blow quickly along the mould line. More expensive European/Japanese tubes rarely blow but are slightly more porous, and will need blowing up more often.
I have been paying a little extra ever since.

The last ones I fitted were heavy duty ones, Michelin I believe, used by scramblers or Moto-Crossers as they call them nowadays. The quality certainly does go down the tubes when they’re made in Taiwan haha

I fitted identical brand new tubes and tyres front and back over winter to my 850GT. The rear stays at correct pressure but the front loses about 2psi per week. Strangely it was exactly the same with the old ones, but that must be a coincidence.

It just doesn’t make sense to me that a bag that is supposed to hold wind - doesn’t I took my Transit camper out tonight to have some repairs done. It has been standing for over a year and the tyres were fine. I’ll check the valves, but probably keep pumping. :unamused:

As an aside, there is an awful lot that doesn’t make sense to me nowadays.

FWIW Have had problems with tubeless tyres losing pressure when the rims are corroded. Or. in the case of a 1970s BMW I used to service, the rims were porous :confused:
And that leads us on to tyre sealant…
All the best

Mhh good question

I had a pair of new tyres fitted with brand new Michelin tubes fitted a few months back by a good tyre fitter and they both go down slowly

The ones that came out would stay up all winter

IIRC there was a thread about this issue a while back lamenting the dumbing down of the inner tube so that it now leaks :cry:

Is that so they can sell more air? :laughing:

Amazingly our local Sainsbury’s air is free.