Last night I came out of work to a flat tire. This is the second time I've got a puncture with less than 100km done on a brand new set of schwalbe smart sam tires. needless to say I was quite annoyed. The first puncture happened after about 40km and the second was after 95km, last night. It was the same wheel both times. After the first puncture, I checked and double checked for any foreign objects in the tire and rim and I found nothing. I pumped the tire and kept it at about 55psi because I read this is good for avoiding punctures. All this to no avail.

I'm just wonder what can I do to stop punctures for good? I'm a heavy guy (about 110kg) so maybe this just isn't possible? I've tried slime before and that was useless. I currently ride on Smart Sam 26" x 2.25

  • First, get Kevlar-belted tires. Second, keep your tires properly inflated, to prevent "snake bite". Oct 19, 2014 at 12:26
  • Removed the product rec portion of the question since we don't do product rec.
    – Batman
    Oct 19, 2014 at 13:52
  • 1
    You are not going to stop punctures for good on a pneumatic tire.
    – paparazzo
    Oct 19, 2014 at 14:05
  • The unfortunate reality is that there is no good way to stop all punctures for good. Even the very toughest tire/belt/tube combo is going to go flat if you hit a self-tapping metal screw, sharp nail, or most other strong sharp things longer than the protective layers of your tire.
    – freiheit
    Oct 20, 2014 at 1:11
  • I'm using Maxxis Aspen and heavy "fat" tubes - no punctures for 500 km (city and xc) for now. And wheels are not loosing pressure!
    – k102
    Oct 23, 2014 at 5:26

5 Answers 5


1) Check and double check for objects in the tire again. Little shards may be completely embedded into the tire. I once had to go through 3 flats, searching every time, before finally finding the little bastard. Bending the tire inwards might help.

2) The Smart Sam exists in a "Plus" version with a 3 mm puncture guard. So if you like the Smart Sam, check out the Smart Sam Plus next time you change tires. I ride another tire with a similar puncture guard on my commuter and didn't had a flat for about 10000 km and counting. Judging by the stuff I find stuck in the tire, the puncture guard has saved me more than a couple of times.

  • thanks for the tip on Smart Sam plus because I had not heard of it before and I do find Smart Sam's to be a perfect all rounder tire. It can quite icy in the winter where I'm from and I don't the thread on marathon plus's would be adequate
    – Ben
    Oct 19, 2014 at 18:12
  • 1
    Knobs help on snow, but they're essentially useless on ice - for ice, pretty much the only thing helps you is studs.
    – Batman
    Oct 20, 2014 at 2:45

There are a few things to do. I'd start by reading this link from Sheldon Brown.

  1. First determine how the flats are occurring.

    • Inspect the tube. Is the rim tape on the rim properly? (if not, you'll see a puncture on the wheel side)
    • Is the tube being pinch flatted? (a snakebite flat, two very closely placed punctures - usually a sign of too low pressure)
    • When you re-install the tube, are you pinching it between the tire bead and the rim? (You can make a rolling motion over the rim with the tire after its seated to prevent this from happening).
    • If you can't find the puncture easily, pull the tube out of the tire, give it some air and then try to find the hissing. If you can't find the hissing, try passing the tube around your lips or dunk the inflated inner tube into water.
  2. Check the inside and outside of the tire for any embedded debris, carefully. If you find some, remove it.

  3. If the tube doesn't have any punctures, is the valve good? Sometimes a faulty valve causes pressure loss. You can either re-core the valve in some cases, or more easily just buy a new tube.

Many manufacturers make kevlar belted tires which have stronger puncture resistance (such as the Schwalbe Marathon Plus), but if your punctures are happening due to rim tape or something, then its not going to help.

If you are running such big tires at 55 psi though, I don't think it's low tire pressure -- I've had about 300 pounds of stuff (bicycle, rider, cargo) on a bike with 26x1.9" tires at around those pressures without any problems on some pretty shabby roads.

If the first flat was indeed a puncture due to debris, my guess is that you didn't actually get all the debris out.


A more puncture resistant tyre isn't going to necessarily help in this situation. If you've come out of work and you've got a flat, it seems like a slow leak. If you didn't find anything in the tyre the 2nd time, I would be checking how you've seated the tyre on the rim, have you accidentally pinched the tube a bit, are the valves in good working order, are the tubes the right size for your 29x2.25 tyres?

When you're at home and have time and focus I would very carefully check the rim & tape for sharp edges, I would turn the tyre inside out and very thoroughly check for embedded objects or grit floating around in the tyre. Further to this, check your tube to see what the puncture looks like (single hole, snake bites, etc). If the tube has already been patched, then ditch it and put a fresh tube in.

As a side note on checking the tube and tyre for objects and puncture cause, you could mark the tube with a piece of chalk where the valve is so that when you take it all apart you can line the valve up with where it was on the tube so you can more easily inspect the tube puncture site on both the tyre (inside it) and the rim. I find this can be helpful to quickly identify the most likely site of tyre/rim damage.

But simply the best way to never get a puncture on a bike again is, don't ride. But we all know that isn't going to happen is it.


Walmart was selling foam inserts that would replace the tube. This would eliminate any chance of a puncture. The disadvantage was weight. The one I handled was about 50% heavier then a convenrtional tire and tube.

  • 3
    A foam tube or other airless tire or tube will be flat-proof. It will also have a high risk of allowing the tire to pull off the rim when cornering, give a harsh ride (just one small spot absorbing bumps instead of the whole tire), have increased risk of rim damage, have worse traction, higher rolling resistance, higher weight, be amazingly difficult to install, and may actually be illegal where you live. They're an outdated technology, obsoleted over 100 years ago. More here: livestrong.com/article/222689-airless-bicycle-tires-review
    – freiheit
    Oct 20, 2014 at 1:06

put carnations condensed concentrated milk into your tube take out valve stem get a applicator bottle u need a hose that will either snug over stem or inner to fill up tube use half a can to a can per tube 3 fl oz should due. this id recommend if u are a green slime believer depending on thickness and type tires entry level regular tires no high end racing or rolled up tires!1 more method adhesive spray and use a bad tube spray inside of tire cover inner topside only cover with spray adhesive very well and cut off old valve stem apply old tube to the inside of good tire let set for awhile then re install

  • 3
    Welcome to Bicycles SE. We ask that you write to the best of your ability on this site. This means proper capitalization, proper punctuation, and complete sentences. Your lack of sentence structure makes it very difficult to understand what you are suggesting.
    – jimchristie
    Oct 24, 2014 at 20:35

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