Taping technique - valve extenders

PolderRider
PolderRider Posts: 69
edited May 2019 in Workshop
I use veloflex tubulars with removable valves on deep section wheels. To date i have used electrical tape on the end of the valve extender before screwing into the valve as a means to improve the integrity of the seal.

This approach has served me well for the past two years. But after a 100km ride yesterday, i checked tyre pressures and they had deflated more than expected. I realise this is an inherent characteristic of tubulars, but i'd like to preserve the pressure at the start of a ride for as long as possible. Taping technique is one area i could be more informed on.

I presume this is covered in other tubular threads so if you have a link by all means pls share. Failing that, can others with similar wheels share their techniques.

Comments

  • imposter2.0
    imposter2.0 Posts: 12,028
    I've never taped valve extenders and never had any pressure-loss problems. If your tubs have latex inners, then that might account for some pressure loss, but any more than a handful of psi over a few hours and I'd be looking for punctures..
  • jgsi
    jgsi Posts: 5,062
    ]Electrical tape is far too thick. Most extenders do have their own little rubber grommet to seal the join but if you do want to use tape, a bit of ptfe on the thread will suffice.
    Use a decent tool to nip up the join and also check that the core is also tightened up.
    ONECOL.jpg
    Those faffy little black things best for emergency especially those made of plastic.
  • Matthewfalle
    Matthewfalle Posts: 17,380
    errrr - no. there is nothing inherent about tubulars losing air. they do not do this.

    user error.

    as above, ptfe tape on extender to valve join and do up nice and tight.

    #simples
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • sungod
    sungod Posts: 16,511
    tubs with thin latex inner tubes (i.e. veloflex) tend to lose pressure much faster than tubs with butyl ones, narrower tubs especially as they have proportionately greater surface area vs. volume

    so while a conti tub may only need a top up once a week, a veloflex will need it ever day

    for a veloflex criterium/carbon, 1-2 bar over 24 hours is fairly typical, for the narrower sprinter 2-3 bar

    if you're seeing more than that, suspect a leaky extender or valve, also the possibility of a thin spot on the tube

    as above, extenders have an o-ring seal, these can get damaged/worn over time, a couple of wraps of ptfe tape on the threads is all that's needed if an extender is a bit leaky, though i tend to replace them if they get this worn

    not all tubs valve stems and extenders are the same, with veloflex tubs i find conti extenders with their thin o-rings are more likely to go leaky over time than vittoria extenders which have a much better o-ring

    if you really want to reduce loss of pressure you can put sealant in to coat the inside of the tube, but that's not good for a nice tub
    my bike - faster than god's and twice as shiny
  • Alejandrosdog
    Alejandrosdog Posts: 1,975
    wot sungod sed

    sorry MF

    #hesrightyouknow :)
  • Matthewfalle
    Matthewfalle Posts: 17,380
    so why don't my tubs deflate? oh, its because i didn't get latex ones which, much like latex inner tubes, do go down.

    its not an inherent trait of tubs, its an inherent trait of all latex tyres.

    so i am correct. and so is that other bloke.

    #equalcorrectness
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • imposter2.0
    imposter2.0 Posts: 12,028
    We're all correct. But only two of us are using pointless and unsupported hashtags.
  • When I was using tubs and deep section wheels the standard means of sealing the extender was plumbers PTFE tape. Cheap as chips and one roll will last forever.
  • PolderRider
    PolderRider Posts: 69
    Right, off to buy some PTFE tape then (god knows what that is in Dutch...anyone?)

    Failing that, i'll join MF and get me some butyl tubs.

    Learnt something so cheers all for chipping in.
  • Matthewfalle
    Matthewfalle Posts: 17,380
    #pleasure
    #bigfamily
    #thoughtsforOxo
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.