CityCyclingEdinburgh Forum » Questions/Support/Help

new tires blowing out

(21 posts)
  • Started 13 years ago by ruggtomcat
  • Latest reply from minus six
  • This topic is resolved

  1. ruggtomcat
    Member

    So my new Conti's arrived today, with two 'free' innertubes, which is nice, because when I was fitting the second I blew two inner tubes. The first time I'd gotten to about 40/50psi when there was a creaking and then BANG! (its hard to convey in text how loud this was, but if you've played a first person shooter and been subject to a flash-bang then you get the idea) The sidewall seemed to have lifted off one rim and the tyre blown out from there.

    As you may know I am no greenhorn and have fast-fitted many a tyre on a late night rainy commute, however I concluded that id been remiss in my mounting and so set to again (after a little break to recover my heart rate) put an old tube in, set everything square, and very slowly tried again, got to 50... 70..80... .. . nothing. bounced it off the ground, all ok.... went to put the locking washer over the valve stem and BANG!!!

    So. I have checked the entire rim for defects, its true and smooth and cute, the tape is unblemished and i have removed every last morsel of dust or grit from the innertube area, refitted the tire with least possible use of lever, and am now too scared to go further...

    This is my last tube.. the blowouts were beyond repair, is this a defect in manufacture? does anyone have ear plugs?

    Posted 13 years ago #

  2. wingpig
    Member

    Superdrug's earplugs might still be on offer at two packets for GBP2.50. Were the blown tubes the freebies?

    Posted 13 years ago #

  3. ruggtomcat
    Member

    one free, the other from the old tyre which although patched had been cruising round quite happily at 80psi for the last couple months. The Front wheel continues to not explode.

    I found this wich has halfway down:

    For people with tyres that appear too big, so it's tricky to fit and inflate them without one section lifting too high and maybe even blowing over the rim, first check for kinks, then if necessary build up the rim. I use PVC insulating tape, taking care to ensure that it goes right into the corner between the bead seat and the rim wall. The rim is often wider than the tape, which I divide by slitting the outside of the roll with a Stanley knife and then tape each side separately. (Not because I’m mean, but to avoid filling the well with a double thickness of tape!) Wrap the tape around once or twice for an uneven seater, three or four for a blower, or as many times as it takes to make a diameter on which the tyre fits snugly.

    but the rims should be the same? When removing the old tyres if anything I found the rear (problem) hoop to be marginally more difficult to disrobe.

    Posted 13 years ago #

  4. Dave
    Member

    Well, faff though it may be, I would remove the first (successful) tyre and fit it on the exploding rim. Either it will explode too (indicating a problem with the rim) or it won't, in which case I'd fit the suspect tyre to the front - if it blows, then suspect the tyre. Unfortunately it'll probably be fine, leaving you to fear either a front or rear blowout for the rest of time!

    Posted 13 years ago #

  5. ruggtomcat
    Member

    Plucked up the courage (and found my earplugs) and took it outside for very slow and cautious inflation....

    seems ok..

    bounced it around...

    lent on it...

    nothin.

    Im not nervous. nahh. no way.

    Posted 13 years ago #

  6. kaputnik
    Moderator

    The first time I'd gotten to about 40/50psi when there was a creaking and then BANG!

    This happened to me on the morning of the Trossachs Ton - my slick tyres had "just" arrived the night before and I was putting the second one on half asleep at 530AM to cycle across to where I was getting picked up.

    BANG!

    Certainly woke me up and instilled a fear of exploding tyres ever since.

    Posted 13 years ago #

  7. ruggtomcat
    Member

    Have they been ok after that? I did a wee run on them today and all seemed well.. they are considerably better rolling than my old tyres, even if they are a bit heavier.

    They really surprised me actually, i thought i was getting slicks at least as wide as my old tyres, but instead they are the narrowest tyres Ive ever used. I feel like a roadie! Sorry, I mean 'lycra-loon'.

    I will write a full review (maybe for citycycing) in a couple of weeks once they've had a few miles.

    Posted 13 years ago #

  8. kaputnik
    Moderator

    Have they been ok after that?

    Touch-wood they have been fine, I've just been careful putting them on, taking them off, make sure they are seated well, put them up to half pressure, check again that none of the beading looks to be bulging before pumping them all the way up.

    They are folding ones so I don't know if that's got anything to do with it bearing in mind this would have been the first time I tried to put a foldign tyre on.

    Posted 13 years ago #

  9. Min
    Member

    "Certainly woke me up and instilled a fear of exploding tyres ever since. "

    That is a perfectly reasonable fear. I have had a fear of exploding tyres ever since my front one exploded while I was riding up a hill, pitching me over the handlebars and grinding my head into a granite chip surfaced road.

    Posted 13 years ago #

  10. Stepdoh
    Member

    They are thin aint they. I went from mtb tyres to Schwalbe Cityjets and though, wow they are thing, then went to the conti ones which were even thinner!

    Posted 13 years ago #

  11. steveo
    Member

    Going between the 23's on the roady and the 2.3's on the mtb is quite an odd sensation, going the other way is frankly worrying.

    Posted 13 years ago #

  12. earthowned
    Member

    I'm resurrecting this thread as both my inner tubes exploded last night once I had got home. My only explanation is that I had pumped up the tubes to the maximum pressure in the cold, then when I got home after a couple of hours the ambient temperature inside the flat caused the gas to expand beyond the tubes breaking point. BANG.

    Posted 8 years ago #

  13. crowriver
    Member

    Yep. that sounds about right. Also maybe avoid leaving high pressure tyres pumped up to max sitting in the summer sunshine for too long...

    Posted 8 years ago #

  14. neddie
    Member

    Unlikely that a temperature change caused the blowout.

    Gases follow the "PV/T = constant" law (P = pressure, V = volume, T = temperature in Kelvin).

    So lets say the temp changed from 273K (0degC) to 293K (20degC), the pressure would only increase by approx 7%.

    I'd be surprised if an over-inflation of 7% above max pressure would cause a blow out.

    Posted 8 years ago #

  15. earthowned
    Member

    I'd be surprised if an over-inflation of 7% above max pressure would cause a blow out.

    It might if you buy cheap Planet X tubes in the sale....

    Posted 8 years ago #

  16. Murun Buchstansangur
    Member

    @earthowned

    Vavert?

    Posted 8 years ago #

  17. earthowned
    Member

    @Murun

    No, the Planet X branded ones at £1.79 each. I didn't realise the Vavert ones are even cheaper at £1.49!

    But, apparently you do get exactly what you pay for.

    Posted 8 years ago #

  18. wingpig
    Member

    I have a couple of cheap Planet X tubes demoted to being spares only as they were distinctly uneven in width and exacerbating the wobble caused by a wonky Gatorskin, which I'll eventually get round to sending back to Continental (along with the other of the pair which let some glass through after less than a week) with a whinge about how crap they are. About twelve years ago I bought a big box of ten Vittoria tubes which lasted me for about nine years, so I bought another box of ten a couple of weeks ago.

    Posted 8 years ago #

  19. Arellcat
    Moderator

    Earthowned, was there any damage to the tyres? Where did the tubes rupture? Both tubes at the same time is quite remarkable. How cold was 'cold'? Also, maximum pressure is probably 100psi plus or minus about 50psi, so perhaps the tubes were not up to the job, or the tyre carcass failed, or the pressure pushed the tube out between the tyre bead and the rim.

    Going back to RTC's comment, I well remember my bike's back tyre exploding about six inches from my right ear. I'd only just mounted and inflated it, and the noise was shockingly and worryingly loud.

    Posted 8 years ago #

  20. earthowned
    Member

    @Arellcat

    No visible tyre damage (folding Schwalbe Ultremo). I should have explained that there was about 30 mins between each poppage. I should have had the sense to deflate the second tyre but it's easy with hindsight.

    At 7am the tyres were pumped up outside at about 0 degrees to about 100psi. Got home about 6pm and 2 hours later parked inside the flat (about 20 degrees) they exploded.The tubes ruptured along their sides in a linear tear a few inches long. The tyre bead was pushed or blown off the rim where the failure occurred.

    Posted 8 years ago #

  21. minus six
    Member

    Had an explosive front tyre blow-out while caning it over Dean Bridge last week

    Bit of a mystery but i suspect poor mudguard seating might have been the causal factor

    Might abandon blind SKS loyalty for those Portland Design Works fenders

    Posted 8 years ago #

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