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Tyre / innertube mismatch

(12 posts)
  • Started 9 years ago by sallyhinch
  • Latest reply from crowriver
  • This topic is not resolved

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  1. sallyhinch
    Member

    I was out on a ride on Saturday and my rear tyre blew (it turned out to be a failed patch - the second one on that tube). I didn't have a spare and my companion only had a much skinnier one, but we fitted that anyway and it held fine - I did about another 30 miles on it that day.

    My question is, what are the implications of keeping running on that tube? Was it only good as a 'get you home' repair, or can I just keep going for a bit until I next put the bike in for a service (which will be in a couple of weeks)? More urgently, should I arrange to get a lift to the pub (8 miles) this evening or just cycle as normal? (or put the ice tyre wheel on?)

    I don't really understand tyre sizing, but the inner tube that used to fit says 27x 1 1/8 - 1 1/4 on it and the inner tube that went in was a fair bit thinner but I didn't make a note of the size, and the tyres are marathon pluses so I'm reluctant to take them off if I don't have to. And I don't have any spare inner tubes that are in any better nick - my other spare has two patches on it already and one of them looks a bit ropey too.

    Posted 9 years ago #

  2. wingpig
    Member

    Narrower tube = more stretched to fill wider tyre = more likely to catastrophically burst-balloon-pop upon its thinner-stretched skin being poked with a spikey thing, whereas a wider tube might cope for longer before succumbing more gently to being spikey-thinged?

    On the 35mm-38mm-tyred sparebike I can notice the narrower bit on a patched tube where the patch reduces the expandability of a section, which is another reason for eventually replacing patched tubes with a fresh one and keeping the patched ones as emergency-spares.

    Posted 9 years ago #

  3. sallyhinch
    Member

    should I maybe let a bit of air out?

    Given the weather (just started sleeting) I may scrounge a lift anyway

    Posted 9 years ago #

  4. kaputnik
    Moderator

    On purely anecdotal evidence, on an unpatched tube, not much difference at all going from a skinny to a medium tyre (i.e. one size up in the manufacturer's guide) and I'll happily shove a tube marked 18-25c in a 32c tyre with no apparent problems. Tubes are made with certain tolerances and will take stress/inflation further than what's written on the tube before they go pop. You just couldn't sell a tube with a 110psi limit that goes bang at 115psi, likewise a tube that says up to 25mm on it can't go bang at the next standard tyre size up (28mm) due to the imprecise nature of actual tyre size dimensions compared to whats written on the sidewall.

    Of course all this could be cobblers.

    I wouldn't put an over-wide tube in a narrow tyre though if you can avoid it due to the surplus of rubber and likelihood of tube forcing the tyre off the rim as it comes up to pressure.

    Posted 9 years ago #

  5. DaveC
    Member

    If you have ever pumped up an inner tube out in the open to find a punture, you'll see they can get quite huge when pumped up.

    I've had the opposite problems before, trying to shove a 32 inner tube into a 25 tyre and having to cram it all in. I've also seen a fellow on an audax tie a knot in an inner tube to get him along! I wouldn't advise that one as a permanant fix mind!

    Posted 9 years ago #

  6. sallyhinch
    Member

    OK. Looks like the pub beckons but I will take a taxi number and emergency fare money with me. The main pain is I now have one presta and one schraeder valve to deal with, so I will also pack two pumps.

    Posted 9 years ago #

  7. I were right about that saddle
    Member

    The pub beckons at 16h30? You dilettante, you.

    While we sit bousing at the nappy,
    And getting fou and unco happy,
    We think na on the lang Scots miles,
    The mosses, waters, and chicanes,
    That lie between us and our hames

    Posted 9 years ago #

  8. SRD
    Moderator

    I would have voted for winter tyre, if your forecast at all like hours.

    then again, i left bike at home, so have been experiencing Dundee's non-integrated public transport 'network' as in: 'get off at debenhams, cross the road and go along there, where that bus is, then turn, the follow along, then past the constructions hoardings, then you're at the train station.

    Posted 9 years ago #

  9. crowriver
    Member

    "have been experiencing Dundee's non-integrated public transport 'network'"

    A bit like the Edinburgh tram/train 'interchange' at Waverley station then? (Though buses are much better integrated).

    At least Dundee has the excuse that they're currently building a new station...

    Posted 9 years ago #

  10. SRD
    Moderator

    oh, is that what that is? interesting. hope they route some of the buses somewhere near it?

    Posted 9 years ago #

  11. sallyhinch
    Member

    haha - pub was a MEETING and it takes me an hour to get in so I had to leave at 5 for a 6pm start.

    The inner tube held fine for the 16 mile round trip but I get the distinct impression that my back wheel is not as round as it used to be. Time the poor old bike went in for a thorough service

    Posted 9 years ago #

  12. crowriver
    Member

    "hope they route some of the buses somewhere near it?"

    I'll not hold my breath...

    Even if they don't, it'll be less of a walk to the new frontage I'd imagine.

    Posted 9 years ago #

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