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December 15, 2017
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  • Dave

    Great article, but I’d just like to suggest an extra point about the ‘water as lubricant’ theory. I think it would make more sense if you could think about it as being dry road debris vs wet road debris rather than dry/wet tyre.

    I do get more punctures in the wet than the dry, despite clocking up much less distance on each of my bikes – although a bit more than usual this year as it’s quite a wet year so far in Adelaide with 31% more rain than the average for January to June.

    • Stuart Matheson

      I thought the ‘water as lubricant’ theory applied specifically to glass
      shards. That matches with my experience pretty well. Think about riding over concrete wet and dry vs riding over glass wet and dry.

    • damienwalder

      The various contaminants on the roadways – propyline glycol, gasoline and oil – make a slick/slurry in the early stages of a heavy rain – these might also act as better (worse?) lubricating aids to the water and debris.
      Another factor in so many flats acquired during rainfall is the lowered visibility – to expand; the preoccupied rider compensating for changing road conditions –
      including ‘dancing’ water concealing sharp debris – has less time to survey approaching surface.
      With over 1000 flats repaired in close to 2 decades working on commuter bikes, I’m not discernably closer to figuring this out than your good self.
      Investing in better tires and checking their health/pressure is never bad advice.

  • Warwick

    Great article. Adding to the anecdotal evidence on latex tubes; I’ve never experienced a puncture using latex tubes after many years of running them on my race wheels and training wheels, but have had the odd puncture when running butyl tubes. The flexibility of latex tubes is supposed to mean more comfort on the road too, which I would agree with.

    • Alan Clark

      The fact that latex tubes are more flexible does make them more resistant to punctures if the thorn (or wire, or glass) just penetrates the casing and then removes itself. Latex is more susceptible, though, to abrasion. If the thorn stays in the tire for a few rotations with a latex tube, punctures are actually more likely.

  • singlespeedscott

    I have found that narrower tyres,ie 23-25mm, tend to get more punctures than my 28-32mm tyres. All these tyres are essentially the same tyre with a different width.

    • Dave

      I’ve found that tyre quality matters a lot more than tyre width. For road cycling, I’d take a good 23mm tyre over a poor 25/28mm tyre any day.

      Unless you’re getting a fully customised assembly with your specified tyres, the first thing you do with a new bike is take the cheap stock tyres off and replace them with good tyres.

    • jules

      Higher pressure in narrower tyres

    • damienwalder

      Allowing for the more probable pinch flats?

  • Peter

    The stock 23 mm tyres which came with my last bike flatted more frequently in the rain than in the dry. But since I’ve used a more puncture resistant 25mm tyre I have had only one flat when a thin piece of wire about 30mm long went through the tyre in the dry. Hard to avoid that one. My experience is that cheaper, thinner tyres flat more in the wet than the dry but that tyres with better puncture resistance are good in wet or dry.

    • Dave

      I’d say that just shows that high quality tyres puncture less than the low quality tyres, regardless of the surface of the condition at the time.

      Better tyres would come quickly if racing rules required the riders to deal with their own issues short of a badly broken frame or wheel. Competition improves the breed.

  • Benjamin

    I’ve always considered type pressure making a difference where a lower tyre pressure usually seen riding in wet conditions sees more punctures on average. I’m thinking the extra firmness of a road tyre at say 120 psi deflects more debris that one at 90 psi. On the road bike I use 110-120 psi in the dry and 90-100 in the wet for a 23mm tyre. I also see generally more punctures riding on cycleways and shared paths where the surface isn’t swept clean by regular traffic.

    • singlespeedscott

      I didnt think anyone ran their tyres this hard anymore? I certainly wouldn’t use those sort of pressure unless I was riding on baby smooth hotmix.

      I am of the opinion that a tyre at lower pressures is going to wrap around and roll over puncture causing piece of debris. A tyre pumped up too hard is just going help drive it into the tyre because the tyre has no give.

      • Irenemlopez1

        <<o. ?????????????????????????????????????????????????????:::::::!!be947p:….,..

      • Benjamin

        I go with the manufacturer’s recommendations for psi, especially with tubulars on one bike that I definitely don’t want to get a puncture on. :-)

        Check out this conti chart for one of the most popular clinchers around. Even the 28mm range is 95-115 psi! Anyway it’s a starting point to experiment by.


        • It’s worth having a look at what Josh Poertner is publishing on Silca’s website: https://silca.cc/blogs/journal/part-4a-rolling-resistance-the-history-and-previous-works

          • Benjamin

            That’s pretty interesting, especially the real world results. Thanks for the link! When I pump up my tyres I’m thinking first of how I want them to feel around corners in the conditions of the day, then puncture avoidance is next on the thought list. Any info you know about tyre pressure and cornering? Different road surfaces don’t worry me too much in general, but I try to avoid imperfections either by steering around, lifting front or both wheels or just standing a bit and letting the legs do their thing. Similar to MTBing.

      • winkybiker

        I run my 23mm 4000s tyres at 115psi. But we are lucky enough to have nice smooth hot-mix pretty much everywhere.

  • David

    Tacks on the Yarra Boulevard get through in both wet and dry conditions. But I feel the wet is useful as it washes debris into the little cracks and faults in the road surface. Cyclists should therefore avoid those faults wherever possible.

    • Tim David

      And on that note, there’s some data you may find interesting if you’d like to prove that more punctures happen in the wet.

      I had a theory that the Kew Tacker’s (the person laying the tacks on Yarra Boulevard) strikes could be identified using Strava data.
      Checking segment activity over 6 years and looking at how often riders stop for more than 5 min and trying to spot a pattern.
      See analysis for Yarra Boulevard here:

      Maybe you could use this data and combine with historic rain data?

      • jules

        I reckon you’ll find punctures there correlate with when tacks are dropped

        • Tim David

          Yes Jules, I think you’d be right, for the period Feb 2014 onward.

          There’s good data back to 2010 and then some data back to 2007 (from Strava’s early adopters). It’d be interesting to see if the likelihood of stopping (which was roughly 1% pre 2014 and roughly 2% now) rises on wet days.

  • Peter Moline

    I would love to see an add-on or feature in Strava to allow riders to log punctures. It could collect some basic info such as weather, road surface, and type of tyre. I wonder whether we could convince the tyre manufacturers to fund it, in return for anonymised access to the data…

    • Yep, this is a great suggestion. If nothing else, it would be interesting to see if there were puncture hotspots.

      • winkybiker

        Yeah, but that tack boulevard in Melbourne would cause my computer screen to burn out.

  • Milessio

    As I tend to puncture around once every 1,500 road kms, it’s statistically hard to determine if rain has any part in the cause. In the wet it is harder to see road debris & pot holes, but that is also the case in the dark, so so do we puncture more in the dark?

  • Hrvoje

    I have two road bikes, one for dry weather, other for rain with disc brakes. Both were used with same tires – Continental GP4000S2, both in 28mm. I mostly ride the same route, and I have witnessed many more punctures on the rain bike. Compared during one season, rain bike had much more debris in tires (mostly small pieces of glass), while tires on the bike used in dry condidions had almost none. I have changed tires on rain bike to Schwalbe Marathon Supreme in 35mm, and so far I had no punctures and it seems much better regarding the debris in rubber.

  • Nick Squillari

    The issue with rain, that I find, is not so much what it creates (in terms of debris or adhesion) but rather what it hides. Dry road glass shards are easily spotted, in the rain not so much. Both from the rain itself in my eyes and the change in colour and contrast on the road. So potential puncture material, that would normally be avoided, suddenly has a lot more risk of being run over and puncturing a tyre.

  • Saisan

    potentially a great topical article. In reality this story was mediocre at best. I don’t want to be negative but it really is a poor effort. The only time I have ever had a flat (I only ride tubulars) is when the road is damp. In heavy rain it is ok, the gyro effect of the water cleans the tyre more or less. On a damp road small debris sticks to the tyre, this situation, being shards of glass or a sharp stone penetrated the tyre thanks to the lubucating effect of water. For any tyre manufacture to say water has no effect on puncture resistance, this is a complete lie! The topic of punctures is as old as the tyre itself. Perhaps the focus should have been on the veterans who have more experience than the industry care to know. Ask a ex-pro in their 60’s or 70’s. They will tell you why you get a puncture when the road is damp.

  • Cyco

    Talk to the people at Michelin. Many years ago they told me that the Silica/Rubber compound could be made to be softer in the rain. Not sure if it is still the case.

  • scottmanning

    I’m one of those rare ones then. I would agree that some roads with level or elevated shoulders, primarily in rural areas, have debris washed onto them but then, only on the very edge. Paved roads are built to shed water from the centre to the sides. Install a gutter facilitating this run off and in 99% of cases debris are in fact washed off the road and into the drains during rain. Even a case where water is running off the shoulder onto the road the debris are kept on the edge which is one more reason not to ride on the very edge. I agree there are cases where debris increase but that surely is a rarity and certainly not the norm.

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