# What's causing my flat tires? Need answer fast **URL:** \ **Category:** Factual Questions\ **Created:** [July 22, 2013, 9:32pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255 "2013-07-22T21:32:43Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 22, 2013, 9:32pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/1 "2013-07-22T21:32:43Z")
About four weeks ago, I got a flat tire on the rear wheel of my bike as I was riding. OK, that one was no mystery: I pulled a couple of nails out of the tire. The patch job didn’t work too well, so I just replaced the whole tube. A couple of weeks after that, I was riding down a different stretch of road, and got another flat, in the same tire. No cause was apparent this time: I didn’t find anything in the tire, nor see anything obvious in the road. So I shrugged and called it rotten luck, checked for any debris in the tire, and replaced the tube again. Well, this morning, I rode to work, parked my bike, and it was fine. Come out this afternoon, and the same tire is flat again. As the saying goes, once is happenstance, twice is coincidence, three times is enemy action. Clearly, there’s _something_ now causing my rear bike tire to go spontaneously flat… But what? What should I be looking for, and how should I fix it? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 22, 2013, 9:34pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/2 "2013-07-22T21:34:56Z")
Since you have tubes I’d look for something sharp on the rim or the inside of the tire. ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [July 22, 2013, 9:44pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/3 "2013-07-22T21:44:12Z")
A bad spoke poking thru the rim (even just a little bit)? May not be able to tell with a casual glance. Does your tire have any sort of fabric or metal mesh? A frayed seam? Invisible giant wasps? ---
**Author:** ![Busy\_Scissors](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@Busy\_Scissors](https://boards.straightdope.com/u/Busy_Scissors)\ **Post date:** [July 22, 2013, 9:50pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/4 "2013-07-22T21:50:26Z")
Like tripolar says - When you got the puncture, did you relate it’s position on the tube to the position on the rim and tyre? If it’s three times in the same place it’s likely a small piece of glass buried in the tyre - they’re sometimes hidden and you need to really prise them out. Second likeliest thing is that there is some rough metal on the rim that’s doing you a mischief. Examine the spot, file down if necessary and re-tape with new rim cloth. You can tell by looking if the puncture is a literally that - you ran over something sharp and pokey, or if it’s a compression puncture where you bashed the wheel on a pothole and the tube got pinched onto the rim. The latter case will have two holes - sometimes called a snakebite flat. If it’s that then you just got unlucky and it’s likely your set-up is fine. ---
**Author:** ![aNewLeaf](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@aNewLeaf](https://boards.straightdope.com/u/aNewLeaf)\ **Post date:** [July 22, 2013, 9:50pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/5 "2013-07-22T21:50:36Z")
thorns :sad: ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 22, 2013, 10:06pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/6 "2013-07-22T22:06:13Z")
I never got around to checking where the holes were in the previous flat (since I had a spare tube, I relegated that task to a convenient weekend that hasn’t happened yet, rather than doing it immediately). The current flat is still on the bike-- I’ll see if I can relate the location this time. I don’t think the tires have a metal mesh: They’re pretty cheap, and I’d expect the mesh would cost more. A bad spoke or an embedded object are still possible, though. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [July 22, 2013, 10:10pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/7 "2013-07-22T22:10:47Z")
Bad valve stem. Or bad valve. Although a run of bad valves would be pretty epic bad luck. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [July 22, 2013, 10:25pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/8 "2013-07-22T22:25:08Z")
air just wants to be free. i’ve found wires and embedded glass chips only found by carefully feeling the inside of the tire. relating tire, tube and wheel position is important in finding the hole truth. ---
**Author:** ![Kenm](https://avatars.discourse-cdn.com/v4/letter/k/bc79bd/32.png) [@Kenm](https://boards.straightdope.com/u/Kenm)\ **Post date:** [July 22, 2013, 10:32pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/9 "2013-07-22T22:32:06Z")
Your arch enemy. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [July 22, 2013, 10:56pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/10 "2013-07-22T22:56:22Z")
You do have rim tape - right? Rubber or plastic strips that protect the tube from the spoke heads which may protude a little too far or have a burr on them. I’ve also used 1/2" fiberglass wrapping tape. Otherwise, you have something embedded in the tire. Glass, thorn, or steel fibers from worn out steel belted radial tires deposited on the road side. Run your naked finger(s) both directions around the inside of the tire. Where you get gashed is the culprit. Your shots should be up to date:D. Years back, consults T-shirt (1989), we were out in Flagstaff area and at the time, bicyclists could use I-40 going west out of town due to lack of an alternate route. We had multiple flats as you described. Local riders favored tires with a kevlar belt built into the tire, also heavier tubes. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [July 22, 2013, 11:51pm UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/11 "2013-07-22T23:51:06Z")
Could the tube be getting pinched when you’re inflating it? To minimize the chance of a pinch flat occurring, some people apply a light coating of talc/baby powder to the tube before installing it. It reduces the friction and allows the tube to properly set itself when you’re inflating it. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 23, 2013, 12:06am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/12 "2013-07-23T00:06:31Z")
Wouldn’t a tube pinch result in an _immediate_ re-flat, though? And there’s some rim tape on the rim already, but I don’t have any more to apply. ---
**Author:** ![TroutMan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troutman/32/6721_2.png) [@TroutMan](https://boards.straightdope.com/u/TroutMan)\ **Post date:** [July 23, 2013, 12:33am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/13 "2013-07-23T00:33:18Z")
A pinch flat wouldn’t necessarily happen immediately. It might happen when you go over a bump. I wouldn’t expect that twice though unless you are way under-filling the tube or bought the wrong size tubes for the rim. My money is on a thorn or glass embedded in the tire. If so, you probably won’t see it from the outside. You have to feel around inside (and suffer the consequences as **smithsb** mentioned). ---
**Author:** ![bicycleguy](https://avatars.discourse-cdn.com/v4/letter/b/ecd19e/32.png) [@bicycleguy](https://boards.straightdope.com/u/bicycleguy)\ **Post date:** [July 23, 2013, 12:50am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/14 "2013-07-23T00:50:52Z")
Almost for sure, there is something yet protruding through your tire and causing your flats. Two suggestions - get a used dryer sheet and lightly pull that against the inside of the tire. When it snags, you’ve found your culprit. Beats finding it using your fingers, although the finger method is very accurate. Second, I carry a push pin in my flat repair kit. Very useful for digging out sharp objects from the tire. I sympathize with you about the recurring flats, especially about arriving at work just fine and then the tire being flat when you get ready to go home. Always puts me in a bad mood for the ride home. ---
**Author:** ![TroutMan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troutman/32/6721_2.png) [@TroutMan](https://boards.straightdope.com/u/TroutMan)\ **Post date:** [July 23, 2013, 1:11am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/15 "2013-07-23T01:11:41Z")
> [@Chronos](#): > > Wouldn’t a tube pinch result in an _immediate_ re-flat, though? > [@TroutMan](#): > > A pinch flat wouldn’t necessarily happen immediately. It might happen when you go over a bump. I wouldn’t expect that twice though unless you are way under-filling the tube or bought the wrong size tubes for the rim. Oops, I maybe misread what you said - I was thinking “happen immediately when filling the tire,” which doesn’t have to happen. But if you get a pinch flat, the air goes all at once, not a slow leak over the day. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 23, 2013, 1:40am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/16 "2013-07-23T01:40:34Z")
Well, I just fixed it-- It turns out that there was a staple-like object embedded in the tire (keeping track of the relative position of the tire to the tube made it a lot easier to find-- thanks for that). I highly doubt it could have been in there without causing an _immediate_ flat, and I don’t _think_ it was in the same position as the previous one, so it looks like I really was just unlucky. In any event, I’ve put the new tube in, I think I’ve satisfactorily patched the old one, and I have transit directions to work for tomorrow in case this tube mysteriously dies too, so I think I’m good now. Thanks, everyone. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [July 23, 2013, 3:13am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/17 "2013-07-23T03:13:44Z")
It’s also important, just for future reference, to keep your tires inflated within the recommended pressure range to avoid those snakebite flats that Busy Scissors mentioned earlier. The recommended PSI is usually printed on the tire sidewalls, just like for car tires. And when you’re ready to replace your current tires, consider flat-resistant tires (usually lined with Kevlar or similar). For 700c wheels the Specialized Armadillo tires do really well – been a year and a half since my last flat of any sort, when before that they would happen once a month or so. Other manufacturers have similar setups (like the Continental Gatorskin/Gator Hardshell). They’ll make your ride harsher, but if you’re just commuting anyway it’s worth avoiding the PITA flats. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 23, 2013, 3:39am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/18 "2013-07-23T03:39:58Z")
I probably will spring for kevlar tires, as well as goo-filled tubes, eventually (because as you say, flats are a PITA), but they’re probably not in the budget right now. Heck, I should get a whole new bike, too. And my tires are rated for up to 70 PSI, and I usually inflate to about 65. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [July 23, 2013, 3:47am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/19 "2013-07-23T03:47:19Z")
I think if I got flat tires repeatedly, I’d change the wheel that holds the tire. Or take a different route. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [July 23, 2013, 3:58am UTC](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255/20 "2013-07-23T03:58:33Z")
Sounds to me like it might be a staple-like object, but that’s just a guess. 😃 [Next page](https://boards.straightdope.com/t/whats-causing-my-flat-tires-need-answer-fast/664255.md?page=2)