http://citycyclingedinburgh.info/bbpress/ CityCyclingEdinburgh Forum » Topic: Puncture mystery en Wed, 13 May 2026 04:59:04 +0000 http://citycyclingedinburgh.info/bbpress/topic.php?id=12514&page=2#post-147896 Sat, 05 Apr 2014 19:26:29 +0000 gembo 147896@http://citycyclingedinburgh.info/bbpress/ <p>@greenroofer, could be. The extra 5 mm of tread that prevents punctures ( in addition to the Kevlar) will be worn out by 10,000 miles, that is quite a number of miles. There may then be more surface area of the tyre in contact with the glass? This could of course be bunkium.</p> <p>When I dig the glass out it is like tiny little round pebbles but I probably do not dig the glass out often enough. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514&page=2#post-147895 Sat, 05 Apr 2014 18:43:38 +0000 Greenroofer 147895@http://citycyclingedinburgh.info/bbpress/ <p>I spent a very relaxing hour this afternoon going over the problem tyre with a bradawl, picking out all the bits of glass and pebbles I could see. I'm pretty sure I found the culprit for Tuesday and Thursday's punctures. As suggested by david.nutter, it was kind of hidden when the tyre was flat.</p> <p>I'm sure there was more glass stuck in the tyre than I've seen before. It's a Marathon Plus with about 10,000 miles on it. It's still got some tread on it. Is a symptom of them wearing out that more stuff gets stuck in them? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514&page=2#post-147824 Fri, 04 Apr 2014 17:35:17 +0000 I were right about that saddle 147824@http://citycyclingedinburgh.info/bbpress/ <p>Right, if that tyre's flat when I go down to the carpark now I swear I'm having it exorcised. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514&page=2#post-147812 Fri, 04 Apr 2014 15:26:09 +0000 crowriver 147812@http://citycyclingedinburgh.info/bbpress/ <p><em>Guy at work bought a German sit-up hybrid. It came with tubes with old-style Raleigh valves. </em></p> <p>Woods valves? I have these on my Winther Donkey trailer. Presumably they are popular on the continent?</p> <p>Or maybe the old Dunlop valves? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514&page=2#post-147810 Fri, 04 Apr 2014 14:44:45 +0000 ARobComp 147810@http://citycyclingedinburgh.info/bbpress/ <p>New planet x shop is selling inner tubes for £1.50 a pop at the moment.<br /> I never repair on my roadbike, mainly because most punctures are catastrophic (down to hitting a pothole or blown out valve etc) so usually the tube is done. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147808 Fri, 04 Apr 2014 14:37:51 +0000 Cyclops 147808@http://citycyclingedinburgh.info/bbpress/ <p>If you're having mystery punctures check the rim as well. Spokes or nipples poking through the rim tape can sometimes be the cause and I've also seen punctures caused by the join in the rim not being flush and smooth. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147807 Fri, 04 Apr 2014 14:37:28 +0000 I were right about that saddle 147807@http://citycyclingedinburgh.info/bbpress/ <p>The valve core was loose on the tube when I first fitted it. Came loose when I unscrewed the pump a couple of times, so I tightened it <em>with extreme prejudice</em>. Normally I don't tighten anything on a bike without using a torque wrench. Never occured to me to use one there...maybe I should have? Anyone know the standard torque on a Continental Presta valve core? I'll be proper impressed if anyone retains that figure in their wetware. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147806 Fri, 04 Apr 2014 14:30:18 +0000 chdot 147806@http://citycyclingedinburgh.info/bbpress/ <p>"Presta valve core had unscrewed itself because it came out attached to my pump"</p> <p>But it's so rare I've never bothered to work out if all/some/very few presta tubes have removable cores! </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147804 Fri, 04 Apr 2014 14:23:58 +0000 Arellcat 147804@http://citycyclingedinburgh.info/bbpress/ <p><em>BUT sometimes some (types) unscrew.</em></p> <p>For months I had this strange, very gradual deflation of my bike's rear tyre. I was convinced it was a tyre problem, a sort of micro-puncture like a strand of wire or something. I'd just give it a few goes with the track pump every other week and carried on as normal.</p> <p>Last week I rode to work, and at hometime my tyre was flat. I quickly checked the tread and it looked ok, so I started pumping it up. I gave it a good go and the tyre just didn't seem to be getting very hard, so I gave it another go and it still wasn't anything like ride on-able. It must be a puncture! Pulled the tube out and pumped it up, except that I couldn't even get the tube to inflate properly. It turned out the Presta valve core had unscrewed itself because it came out attached to my pump.</p> <p>So I put the core back in and tightened it with my fingers, tube back in, tyre back on, and started reinflating it. Damn it if I still couldn't get the tyre to inflate properly. It turned out my pump (Blackburn Airstik) was leaking air from the handle end, even though it was already fully tightened. By now I had wasted 25 minutes. I borrowed a handily-appearing colleague's pump, which did the job in double-quick time and sprinted into town to meet friends for dinner, for which I was now late. The next day I bought a new pump (Revolution mini track). I'll rebuild my Blackburn and keep it for backup.</p> <p>Sometimes it's a thorn.<br /> Sometimes it's the valve.<br /> Sometimes it's your pump.<br /> Sometimes it's a combination. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147798 Fri, 04 Apr 2014 13:41:06 +0000 acsimpson 147798@http://citycyclingedinburgh.info/bbpress/ <p>@Greenroofer. I had a similar puncture this week while heading along the A90 path. I stopped and put my spare tube on and checked the inside of my tyre. It lasted a couple of miles but punctured again before I got home.</p> <p>I pulled a few bits of glass out of the tyre but nothing big enough that I would expect it to get through a gatorskin. Having patched and refitted the tyre was flat again by morning with a similar looking 2mm hole, although curiously not all the way through this time. I checked the tyre even more thoroughly and pulled out what I can only describe as sand from a few we nicks in the tyre. This time it seems to be OK and I made it into work today. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147797 Fri, 04 Apr 2014 13:33:01 +0000 Nelly 147797@http://citycyclingedinburgh.info/bbpress/ <p>Chap near Edinburgh Park Station the other evening was on (I think) his third puncture of the day, he had done all the right things, run his fingers round the tyre etc to find rogue bits of 'stuff' to no avail.</p> <p>I asked if he needed anything, said he was fine, but he was patching.</p> <p>I am of the lazy type - new tube every time, they are not that pricey, spend the money on decent tyres and one tube every year or so is a small price to pay.</p> <p>Back on topic though - I reckon you have a valve flaw. I replaced a tube a couple of years ago and it exploded in the night - I remember running around the house looking for some reason for the huge bang - about 15 mins into the search I spotted the deflated tyre.</p> <p>Couldnt work it out, thought daft throughts like 'its warm in the porch, the tube was in a cold shed....' but on reflection it was a flaw at the valve. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147796 Fri, 04 Apr 2014 13:27:12 +0000 I were right about that saddle 147796@http://citycyclingedinburgh.info/bbpress/ <p>Emerging themes;</p> <p>Quantum punctures<br /> Stealth punctures<br /> Group punctures<br /> Pseudo punctures </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147792 Fri, 04 Apr 2014 13:10:13 +0000 MediumDave 147792@http://citycyclingedinburgh.info/bbpress/ <p>Re mystery punctures, I had a tiny sliver of metal embed itself in the tyre once. I could not find this with the tyre off the bike, no matter how much flexing or careful feeling around I did. The sliver was almost exactly the same thickness as the tyre itself which may explain its amazing camouflage properties. </p> <p>With the tyre on, tube inflated and the bike unridden, all would be well. My theory is that when riding the bike the pressure of the road caused the little metal sliver to poke into the tube just one...tiny...little...bit and puncture it again. Its work done, it would disappear back inside the tyre again. </p> <p>This mystified and enraged me in equal measure until the mystery metal popped out of the outside of the tyre after fixing the Nth puncture. Gah... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147784 Fri, 04 Apr 2014 12:34:08 +0000 kaputnik 147784@http://citycyclingedinburgh.info/bbpress/ <p><em>I'm a Presta man.</em></p> <p>Guy at work bought a German sit-up hybrid. It came with tubes with old-style Raleigh valves. He has a rather cumbersome-looking converter on them to allow use of a Schrader pump. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147783 Fri, 04 Apr 2014 12:33:47 +0000 Greenroofer 147783@http://citycyclingedinburgh.info/bbpress/ <p>I've had two punctures in two days in the same place on the same wheel with no visible cause. The puncture is a clean 2mm cut in the tube. I've inspected the tyre very carefully twice and can't find a culprit (and anyway, the tyre is a Marathon Plus, so I don't expect there to <em>be</em> a culprit).</p> <p>It's never easy to do a proper check in a dimly lit bikeshed at work (Tuesday) or in rain at Meggetland (Thursday), so I took the other bike to work today and will do a proper check of the whole tyre, tube, rim, rimtape etc over the weekend.</p> <p>There's something wrong. I just can't find it.</p> <p>*Oh yes, and when I got home on Tuesday I found Mrs Greenroofer had a flat in her rear wheel which has hub gears and roller brakes and is a complete pain to remove. I had to fix that too. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147777 Fri, 04 Apr 2014 12:07:10 +0000 acsimpson 147777@http://citycyclingedinburgh.info/bbpress/ <p>With a presta valve it's sometimes possible to tighten it with the pin slightly squint. I don't know if that would cause a quantum deflation event or not though.</p> <p>I always carry a spare tube plus repair kit. On the road I'll change the tube and then repair the puncture at home. The repair kit is in the bag mainly as insurance against Sod's law. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147774 Fri, 04 Apr 2014 11:59:28 +0000 I were right about that saddle 147774@http://citycyclingedinburgh.info/bbpress/ <p>@Roibeard</p> <p>I'm a Presta man. Never understood why Schraeder valves needed to come over here and take our valve seats. They never integrate either. </p> <p>Just noticed that Greenroofer has had two punctures in two days as well...the plot thickens. He comes the same way as me. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147770 Fri, 04 Apr 2014 11:54:50 +0000 chdot 147770@http://citycyclingedinburgh.info/bbpress/ <p>"Shouldn't be an issue with Presta valves"</p> <p>That's true. </p> <p>BUT sometimes some (types) unscrew. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147768 Fri, 04 Apr 2014 11:48:53 +0000 Roibeard 147768@http://citycyclingedinburgh.info/bbpress/ <p>I've an alternative theory if it was a <a href="http://sheldonbrown.com/brandt/presta-schrader.html">Schader</a> (car type) valve.</p> <p>If the valve "pin" wasn't seated properly, the valve itself could have leaked, and it was seated properly on the second attempt.</p> <p>As per my father's practice, I always put a blob of spit on a Schader valve post inflation to ensure that it isn't leaking - a bubble will form if is leaking. In 20 years I've been saved from a handful of flat tyres (bicycle or car) by this method, so the reseating issue isn't frequent, but is possible.</p> <p>Shouldn't be an issue with Presta valves, but someone will be along in a moment to correct me... </p> <p>Robert </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147763 Fri, 04 Apr 2014 11:42:45 +0000 chdot 147763@http://citycyclingedinburgh.info/bbpress/ <p>"IMO if tube has a dodgy valve, best replace"</p> <p>+1</p> <p>Or if puncture 'too' near valve base or anywhere with significant moulding marks/patterns/joins. </p> <p>I have fixed a lot of tubes, quite therapeutic as well as cost saving - only costs 'time' money if you don't have anything else to do while waiting for glue to dry!</p> <p>As I say to kids "what's the most important thing to remember about fixing a puncture? - what do you do after putting on the glue?*)</p> <p>"Lengths of old inner tube come in handy for all kinds of repair jobs, frame protectors, etc."</p> <p>Yeah, if I decide not to fix a tube I immediately cut off the section with the valve. </p> <p>*I have had kids say 'put chalk on' - which explains a lot... In schools a lot of kids say they don't ride their bike because they've got "punctures". Often turns out they just have flat tyres and no pump. </p> <p>'Most important thing?'</p> <p>Four letters -</p> <p>WAIT. </p> <p>Well dried glue increases chance of patch staying on significantly. </p> <p>No fun in rain/dark. </p> <p>Carry a spare (or two) - or enough for a taxi! </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147762 Fri, 04 Apr 2014 11:42:32 +0000 kaputnik 147762@http://citycyclingedinburgh.info/bbpress/ <p>Uses for old inner tube #312.</p> <p>Curing a noisy water tank valve which was sending a loud humming/vibrating noise throughout the whole tenement stair whenever the tank was refilling.</p> <p>Crummy plumber had put the clip around the lagging (internal cold water pipe. why it was lagged I don't know!) and then nailed the clip in, rather than screwing. As a result the clip couldn't hold the pipe tight and support its weight, the piping was slipping down and stressing the valve, resulting in the strange vibrations and noises. </p> <p>Solution: cut of the insulation, bung the gap between the pipe and the U-clip with a wrapping of cut-up inner tube, replace nails with screws. Screw clip tightly to the wall. Rubber grips the pipe but avoids it deforming. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147761 Fri, 04 Apr 2014 11:41:53 +0000 ARobComp 147761@http://citycyclingedinburgh.info/bbpress/ <p>I've had similar before. Basically what I reckon it is is that the patch doesn't stick quite right the first time but when you pump it back up it "takes" the second time. A bit weird but it happens. I've had it where the bike has been super cold and the tyres gone flat- pump it up and it's fine.</p> <p>You might find that it goes down again in a week or so. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147760 Fri, 04 Apr 2014 11:33:12 +0000 gembo 147760@http://citycyclingedinburgh.info/bbpress/ <p>Schwalbe marathon plus with extra 5mm rubber and Kevlar now been totally copied by Panracer. Tyres look identical. Neither will stop blackthorn. You would think MOD would find a way of sticking the blackthorn on the ends of bullets? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147759 Fri, 04 Apr 2014 11:32:56 +0000 PS 147759@http://citycyclingedinburgh.info/bbpress/ <p>I'm with kappers on this. The only time I have had a slow puncture that suddenly cured itself upon re-inflation was with a tyre that had been repaired with a Park patch. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147757 Fri, 04 Apr 2014 11:27:01 +0000 I were right about that saddle 147757@http://citycyclingedinburgh.info/bbpress/ <p>@gembo</p> <p>Dunno! Total mystery. It was on the rim-tape side and too close to the valve stem to be due to pinching or twisting. (I've always liked the resonant 'poing' of an inner tube untwisting itself on inflation.)</p> <p>I'm seriously tempted by the notion of quantum tunneling being to blame. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147756 Fri, 04 Apr 2014 11:24:05 +0000 I were right about that saddle 147756@http://citycyclingedinburgh.info/bbpress/ <p>@DaveC</p> <p>I operate on the three patch/three year rule. Have done since I was an impecunious student.</p> <p>These blackthorn episodes are making me long for the light grey solid rubber tyres on my first tricycle. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147755 Fri, 04 Apr 2014 11:21:49 +0000 gembo 147755@http://citycyclingedinburgh.info/bbpress/ <p>@IWRATS what caused the puncture next to the valve stem? Sometimes if in a hurry I nearly forget to inflate, deflate, re inflate to ensure tube settled twixt wheel and tyre. But secondary loop kicks in in brain stem and routine gets completed. Maybees the tube is not optimal? I have a strike 1, strike 2, strike 3 and out tube rule now, though inspection of older tubes may reveal up to seven patches. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147754 Fri, 04 Apr 2014 11:20:16 +0000 crowriver 147754@http://citycyclingedinburgh.info/bbpress/ <p>Hardly. Only ever owned four bikes from new. The rest second hand. None cost over £600 to purchase (as for maintenance costs, surprisingly little over the years).</p> <p>Even Schwalbe inner tubes only a fiver each. What price your time spent in the rain trying to resurrect a flat by the roadside?</p> <p>IMO if tube has a dodgy valve, best replace. Lengths of old inner tube come in handy for all kinds of repair jobs, frame protectors, etc. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147753 Fri, 04 Apr 2014 11:17:46 +0000 DaveC 147753@http://citycyclingedinburgh.info/bbpress/ <p>Crowriver said "New tube. Sorted. "</p> <p>Oh the opulence!!</p> <p>You can tell those who live in the burgh.... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=12514#post-147751 Fri, 04 Apr 2014 11:10:48 +0000 I were right about that saddle 147751@http://citycyclingedinburgh.info/bbpress/ <p>@kaputnik</p> <p>Liking it. I'd already put the adhesive on when I discovered I'd no classic patches. I let it dry totally (4 minutes 59 seconds, as ever...) before I put on the instant patch. Curing may have been retarded. </p>