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Clarification:

I am not asking for a solution to punctures, or about the nuances of ride quality with the various solutions. I am asking whether one method of reducing punctures has been proven better than others through scientific testing.

Preface:

I often see people online using tubes with sealant rather than tire liners or puncture resistant tires, and wonder "why?" The slime is messy, can clog the valve, weighs more than liners, and does nothing to actually prevent a puncture, but rather waits until the puncture occurs to go into action filling it and (hopefully) coagulating in the hole. I've read that this really only works on small holes, too.

Purely anecdotal evidence:

I've ridden for the last eight years on the same route during my commute. I started with tire liners on regular tires, then went with Continental Gatorskins (Kevlar belted), and am now on my second set of Vittoria Randonneurs (double-shielded), and of the three setups, only ever had punctures on the Conti's -- at least two flats per year (grrr!). Zero flats on the Randos in nearly four years while laughing my way through the fields of glass. I see Schwalbe Marathons recommended more than any other brand, and while many say they've never had a flat with them, I also see some cyclists posting that they've had flats with those, too.

It just seems to me that there's no competition: double-shielding wins, IMO. It's less hassle that liners or sealant, and just as protective as liners/more protective than sealant, and generally weigh the same or less than sealant-filled tubes or tire-liners. Not to mention the cost factor over time.

Question:

Can someone explain the advantages of using liners or sealant over puncture-resistant tires, specifically relating to resisting punctures? Have any scientific studies been done to compare the three methods?

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    No setup (beyond solid tires) is flat proof. Continental Hardshells are more puncture resistant and longer lasting than the Gatorskins, at the cost of a harder ride and less traction. – Rider_X Jun 23 '15 at 15:39
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    I have no expectation of finding a puncture-proof solution. I already have my "solution" on my bike. I'm wondering why some choose to use sealant or tire liners over puncture-resistant tires, and if there's some advantage I'm missing. – digijim Jun 23 '15 at 15:46
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    @digijim - Your question explicitly asks about nuances of ride quality, then deviates into questions about scientific analysis of puncture resistance. I think you need to pick one and rephrase your question. Ride quality has many components (e.g., suppleness, grip, rolling resistance). Puncture resistance impacts these characteristicsl. If, as you state in your comment, you are only interested in puncture resistance then a solid tire will be scientifically best. – Rider_X Jun 23 '15 at 19:12
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    @Rider_X - Show me where I explicitly ask about ride quality, because I honestly don't see it. Everything I read in my question relates to puncture resistance. – digijim Jun 23 '15 at 19:20
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    I've only ever had one puncture in my Forte Metro-K tires (Kevlar belted), in about 3000 miles of riding, and that was when the tire was nearly worn out. Prior to switching from standard tires I got about one puncture every 200 miles. – Daniel R Hicks Jun 24 '15 at 0:18
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There is more to tire set-up than just puncture proof. Many are also interested in tire suppleness, traction and rolling resistance. Tubeless tires are the in thing at the moment because tubeless construction take material away (aka the the tube) and allows lower pressures, which results in a more supple tire, that has more traction and often less rolling resistance.

Supple tires can often roll faster and with less effort as they deform more easily to surface imperfections. This translates into a smoother ride and less pedaling effort and more traction. Many of the puncture proof setups add material to the tire making the tire carcass stiffer, this in turns means it takes more energy to deform the tire when rolling (or encountering a bump), which in turns results in a harsher ride and a higher rolling resistance (the energy to deform the tire has to come from somewhere; i.e., forward momentum).

Summarizing:

  1. Tire Liner - Cheap and reusable as it can be applied to current tires, but has a fiddly set up (e.g., getting the liner to stay in place), will reduce suppleness of the tire and does not provide puncture protection on the side wall.
  2. Puncture resistant tires - These have what is in essence a liner built into the tire carcass. Because of the unified construction should be more supple build than a tire liner and vary the degree of coverage. Different manufacturers and models will have different trade-off between suppleness and puncture resistance.
  3. Tubeless - Primary goal is really to create a lighter, more supple tire, that can be run at lower pressures, the setup also happens to have good puncture resistance properties if sealant levels are maintained. Mounting a tubeless setup can be a hassle (i.e., you need high pressure to seat the tire), sealant is required and handles sealing the system including handling punctures. Sealant also needs to be topped up every few months as it dries out, and without sealant you lose puncture protection. The setup also requires wheels with tubeless compatible or tubeless ready rims, tubeless tape, and tubeless valves are also required. The design goal was less to be "better" than (1) or (2) in terms of puncture protection, but optimizing the tire for a different set of criteria (i.e., weight, suppleness, traction, rolling resistance and puncture protection).

If puncture resistance is your only concern then your "double-shield" setup looks like a good solution and will be easier than tubeless.

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    Tubeless is all front loaded for time required as well. It is the lightest, best "feeling" ride but requires known. up front effort and little effort afterwards. Liners and puncture resistant tires feel less nice while riding and require the same amount of effort as initial setup when they fail (or more). It's an Iron Man vs Wolverine question. Iron Man can withstand quite a bit, but once his armor is penetrated, he's pretty much done. Wolverine can sustain the same damage, but recover from it and keep going. – Deleted User Jun 23 '15 at 16:19
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The tyre slime is particularly good at sealing pin-prick holes... I bought a new ride on mower, and within half an hour got a puncture on the front 2 ply tyre.... I then installed the supplied Goo, and it sealed the leak.

After 3 years of cutting grass (next to Hawthorn Hedges) the front tyres finally needed some air, so I took them off to find the new hole... Each tyre was riddled with over 14 punctures, and the tyres still had many thorns in them.

So the Goo really works, I repaired one tube with a dozen patches, and treated myself to a new tube on one side. I never realised the Goo had sealed so many holes. I also have used it in a slow puncture on a car tyre, also with good results.

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    Hi and welcome to bicycles. SE. This doesn't answer the question, which is asking for a comparison of which approach is better - you've only mentioned one method. – Móż Jun 13 '16 at 21:46
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    As an aside, the goo can lead to an expensive repair on a car tire. A lot of cars have tire pressure monitoring system (TPMS) sensors which are built into the valve, and the goo can interfere with the sensor. Depending on the car, replacement of the valve/TPMS sensor can run hundreds of dollars (for my car, the sensor+valve was a bit over 100 dollars, excluding charges for programming it). – Batman Jun 13 '16 at 22:26
  • What pressure do your tractor tyres run? I would guess fairly low MTB-level pressures. – Criggie♦ Jun 14 '16 at 3:53
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    While it doesn't answer the main thrust of the question, this answer does report on the effectiveness of one approach. I'm voting to keep it. – andy256 Jun 16 '16 at 1:16

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