Tubular Tyres - Pressure

harvoir
harvoir Posts: 58
edited October 2009 in Workshop
Hi all,

I've been inflating my tubular tyres to around 130PSI and for some reason they feel a little soft if i really push my thumb on them after inflation. When I release the track pump valve I hear a short leakage of air, is the track pump faulty, is this normal or am I losing my mind? Surely at this PSI they should be solid?

Why i'm this concerned about rolling resistance when i'm only cycling back and forth work escapes me!

:roll:

Comments

  • oldwelshman
    oldwelshman Posts: 4,733
    Cycling to work on tubs? you have too much money :D
    The valve always looses a bit of air when releasing, about 10psi. I run less pressure in winter on the road anyway, 130 is a bit much IMO.
    http://s290.photobucket.com/albums/ll245/oldwelshman/
    http://www.youtube.com/watch?v=aK5Bfqj5fxY
  • Smokin Joe
    Smokin Joe Posts: 2,706
    The advantage of tubs is that at high pressures they still retain their suppleness which is why they give a little under thumb pressure.

    The air loss you notice on release is from the hose on the pump, not from the valve as is commonly thought.
  • harvoir
    harvoir Posts: 58
    oldwelshman wrote:
    Cycling to work on tubs? you have too much money :D
    The valve always looses a bit of air when releasing, about 10psi. I run less pressure in winter on the road anyway, 130 is a bit much IMO.

    Tubs were not my preference, I inherited the wheels, bontrager carbons, with valve extenders. I've made sure the extenders are a snug fit though.

    Maybe the thumb test is not a reflection of the PSI? My friends clinchers seem more solid!? Maybe it's because i bought cheap tubs? (£15)

    Ta
  • andrewgturnbull
    andrewgturnbull Posts: 3,861
    Hi there.

    I'm not sure about this perceived wisdom that there is a significant loss of pressure when you release the valve. The vast majority of the air you hear hissing out comes from inside the hose of the track pump - not your tyre.

    Cheers, Andy
    http://www.andyturnbull.co.uk
    http://www.stirlingtri.co.uk
  • andrewgturnbull
    andrewgturnbull Posts: 3,861
    Smokin' Joe - sorry I didn't realise you'd posted the same comment, I hadn't read down that far... I also agree about the suppleness of racing tubs, especially if they have latex inners.
    http://www.andyturnbull.co.uk
    http://www.stirlingtri.co.uk
  • harvoir
    harvoir Posts: 58
    Smokin Joe wrote:
    The advantage of tubs is that at high pressures they still retain their suppleness which is why they give a little under thumb pressure.

    The air loss you notice on release is from the hose on the pump, not from the valve as is commonly thought.

    When I first had them I used to feel every bit of dust and gravel from the road, now they feel almost comfortable, i'm obviously getting used to them!

    I've taken all your comments on board and they are much appreciated, I almost bought new tubs today, fortunately I didn't. Thanks.

    It seems the only way forward are solid rubbers tyres, a la your first bike, :)

Categories