Puncture Protection In A Tyre

[Panter]

I don't know about the technicalities of it all, what I do know is that if I run Marathon pluses with their kevlar belt, the shards of glass and arrow head flints jam into the tread and then just fall out after a while.
With the other tyres I've tried, they end up cutting through and into the tube after a very short period of time if not removed.
My new commute involves lengthy sections of glass strewn shared path, on a bad week I was getting 2 or 3 punctures a week. Fitted the M+ over a Month ago now and not had a single deflation.

 

[Yellow Saddle]

I don't know about the technicalities of it all, what I do know is that if I run Marathon pluses with their kevlar belt, the shards of glass and arrow head flints jam into the tread and then just fall out after a while.
With the other tyres I've tried, they end up cutting through and into the tube after a very short period of time if not removed.
My new commute involves lengthy sections of glass strewn shared path, on a bad week I was getting 2 or 3 punctures a week. Fitted the M+ over a Month ago now and not had a single deflation.

Perhaps you will make a good guinea pig at an attempt to quantify "punctureproofness." If you were getting two or three punctures per week and that was a good average over a long period and, you now use different tyres but on the same route, you will still experience the same number of little cuts in your tyre. The difference being that these little glass cuts don't lead to full blown punctures. If you don't mind, set a reminder in your calendar so that in a months time (or perhaps 30 rides' time) you count the number of cuts in the worse of your two tyres and report back here. The ration of cuts to punctures will say a lot.

I think the answer would be enlightening.

 

[Globalti]

Motorcyclists suffer from the same misconception regarding the need for tread although I'm sure their treads are intended as a nod to the requirement of the law. You can't tell me these treads will perform any useful function at all:

 

[Panter]

Perhaps you will make a good guinea pig at an attempt to quantify "punctureproofness." If you were getting two or three punctures per week and that was a good average over a long period and, you now use different tyres but on the same route, you will still experience the same number of little cuts in your tyre. The difference being that these little glass cuts don't lead to full blown punctures. If you don't mind, set a reminder in your calendar so that in a months time (or perhaps 30 rides' time) you count the number of cuts in the worse of your two tyres and report back here. The ration of cuts to punctures will say a lot.

I think the answer would be enlightening.

Done! I've set a reminder on my Google calendar so will check them a Month from now at the weekend.
By the way, I don't claim the M+ as puncture proof, jsut very good puncture resistance. I had one puncture on the other bike (700C tyres) That was a particularly nasty hawthorn that managed to make its way through to the tube.
I particularly remember it as it only just penetrated the tube, but had worn down flush with the tyre on the outside and was completely lodged in there. After struggling to remove it for some time, and with me getting later and later for work, I finally managed to get it out with my teeth. Not something I ever want to repeat, hence I now carry a pair of needle nose pliers around with me!

 

[Yellow Saddle]

Motorcyclists suffer from the same misconception regarding the need for tread although I'm sure their treads are intended as a nod to the requirement of the law. You can't tell me these treads will perform any useful function at all:

They perform at lest three useful functions:

1) The fake tread gives you a good idea of tyre wear and you can insert a pluner vernier in there to measure wear.
2) They serve the superstitions of those who believe that tread is important on all tyres.
3) They give café racers the satisfaction that they're riding on a race tyre that is both wet weather and dry weather optimised.

 

[Yellow Saddle]

Done! I've set a reminder on my Google calendar so will check them a Month from now at the weekend.
By the way, I don't claim the M+ as puncture proof, jsut very good puncture resistance. I had one puncture on the other bike (700C tyres) That was a particularly nasty hawthorn that managed to make its way through to the tube.
I particularly remember it as it only just penetrated the tube, but had worn down flush with the tyre on the outside and was completely lodged in there. After struggling to remove it for some time, and with me getting later and later for work, I finally managed to get it out with my teeth. Not something I ever want to repeat, hence I now carry a pair of needle nose pliers around with me!

Great. Some nice macro photos of those little cuts will also help.
Anyone willing to set up a control? We need someone who rides on thin race tyres.

 

[Smurfy]

This photo shows clearly why aramid fibres are not ideal for tyre carcasses. Aramid is very abrasive and quickly eats the tyre from the inside out. If you look at this photo, you can actually see the 35 degree cord angle which one normally cannot see in a tyre covered with this much rubber.

@YellowTim . Perhaps my knife example wasn't a good one. I should have suggested an awl.

Tyre punctures generally don't happen like needle pricks or knife cuts. They occur because, as you say, a small piece of glass or sharp metal (typically from damaged steel belt tyre) embeds in the rubber of the tyre and then through repeated turns of the wheel, works itself in between the fibres without cutting them. We know it doesn't generally cut the fibres because the tyre doesn't suddenly bulge after most punctures. Cuts of course compromise the casing's integrity and we see those typical bulges or "broken nose" zig-zags in the tyre.

Here's a picture I've taken from: the website you cited for puncture-resistant aramid (Kevlar) gloves. (http://www.turtleskin.co.uk)
View attachment 79649

They explain how they attain their puncture and cut-resistant gloves and it is by way of a fine weave. The needle in the picture is 28 gauge (0.3mm). Both the weft and weave here is also about 0.3mm and thanks to Aramid's abrasiveness, it resists shifting and opening up when a needle is jabbed at it. However, massage that needle a little and it goes right through, without cutting a single fibre. Massaging is what happens in tyres but not in sharps disposal. It cuts as well, tiny glass shards shirter than the tyre is thick, slowly work their way right through. Those of us who ride narrow tyres in cities where bottle disposal is by way of breaking the glass in the street, know to inspect our tyres after each ride and remove glass with a sharp object. This glass is almost never visible on the surface but already embedded yet not completely through. Aramid may or may not slow it down.

Like I said, a better material is vinyl but it deadens the tyre. Next time you are in a bike shop, ask to look at vinyl tyre liner. You'll be surprised at the weight. Open the box and feel it. Tough stuff.

As @victor said, even Marathon tyres are not puncture proof, but resist punctures a bit more than snakeskin-thin tyres.

A material that requires a weave in order to create a flat surface will never be a proper puncture protection agent in bicycle tyres where we cannot build up enough thickness.

Probably best not to bother discussing tyre penetration by tough, long, narrow objects such as nails, needles etc. etc. as in my opinion this type of puncture is relatively rare, and it's not really practical to design a tyre that can resist this kind of penetration.

That leaves penetration by small fragments of glass, which in my experience, puncture resistant tyres are very good at preventing. To understand why these tyres work so well, you need to understand that the ability of a nail, for example, to penetrate the tyre casing, is far superior to a fragment of glass. The essential difference is that the nail has very high toughness, whereas the small fragment of glass has almost zero toughness. To put it another way, it is impossible for a nail-shaped piece of glass to penetrate a tyre. In practice what happens is that the glass just repeatedly fragments, and eventually falls out of the tyre. You can prove this by looking at the pieces you retrieve from tyre casings. You will find that none of these retrieved glass fragments are long and thin, and the highest aspect ratio is I'd guess around 1:2 in terms of width:length. The criteria you need to satisfy, is to try to find a needle-like shard of glass that is 0.3mm wide and several mm long, so as to be able to work it's way through the weave in the way you describe. I guarantee you won't find such a piece of glass anywhere, it's just too brittle.

The other thing you need to understand is that woven aramid fabric in a tyre is not simply a fabric, but a composite. The rubber that has totally impregnated it and saturated it during tyre manufacture is the matrix part of the composite. This rubber matrix is not just the tread, but it also fulfils an important role in holding or 'gluing' the fibres in place, and resisting any penetrating object that attempts to open up the weave and pass through.

I'm probably inviting a puncture fairy visitation, but I'll stick my neck out and say that I wore out my Specialized Armadillos without a single puncture, and I gave up picking out fragments of broken glass from the tread, because I didn't think it made any difference. My daily commute takes me through the centre of a drinking area, where broken glass is common, so apart from dodging obvious areas of smashed glass, and riding well clear of the gutter, my tyres fend off the rest. I'm now on my second set of puncture resistant tyres, I don't bother picking glass from the tread, and ~5000 miles in, fingers crossed, no punctures so far. In fact, having easily got my moneys worth after ~5000 miles of trouble free riding, if I were to puncture now, I'd seriously consider just buying a new pair of tyres.

 

[Smurfy]

Motorcyclists suffer from the same misconception regarding the need for tread although I'm sure their treads are intended as a nod to the requirement of the law. You can't tell me these treads will perform any useful function at all:

Bicycles don't go fast enough to aquaplane, motorcycles do. I suspect the tread is to disperse water, and is probably not as useless as you think it looks.
[QUOTE 3533140, member: 9609"]Although it is not obvious from the above picture the tyre is delaminating, probably 75% of the casing is loose on the tyre. It is something I really don't like about these tyres they seem to look ok at a glance but then have near catastrophic failures. There was a warning to the above failure that I had ignored, it had started to feel a little lumpy in its last few miles, I had presumed this lumpiness was mud caught between tyre and frame. I must remember to make better inspections of these tyres and replace at any signs of delamination.



so this explains why these tyres seem to delaminate, I have had a few of them and they always seem to fail by shedding the casing, . Here is another picture of the casing coming off armadillo's, this was on the front and had done just over 4000 miles.

[/QUOTE]
I never had any trouble with delamination of my Armadillos. Maybe you got a bad batch, or allowed too much casing flex. What pressure do you run? I always keep mine at 120 psi, which wouldn't allow much casing flex, especially as I'm a light rider.

 

[HLaB]

Motorcyclists suffer from the same misconception regarding the need for tread although I'm sure their treads are intended as a nod to the requirement of the law. You can't tell me these treads will perform any useful function at all:

Tread is important for a motorcycle they can go fast enough in relation to their tyre width to aquaplane, a cyclist simply can't; so your half right.

I see @YellowTim said the similar

 

[shadow master]

Puncture protectection seems to be printed on virtually every bike tyre on the market these days,its very simple really most successful protected tyres ie marathon plus etc have a depth of material in the roof of the tyre that exceeds the length of the item that could puncture the tyre,hence the thorn\flint can't reach the tube despite being hammered at 350+ revs per minute.if it can reach you will be

 

[Yellow Saddle]

Puncture protectection seems to be printed on virtually every bike tyre on the market these days,its very simple really most successful protected tyres ie marathon plus etc have a depth of material in the roof of the tyre that exceeds the length of the item that could puncture the tyre,hence the thorn\flint can't reach the tube despite being hammered at 350+ revs per minute.if it can reach you will be

It is an easy claim to make since it is meaningless and difficult to prove or disprove. It reminds me of those beauty product adverts on TV - visibly reduces wrinkles (says 10 out of 27 women polled). What they don't tell you is that all the women in the poll were 16 years old.
The same goes for puncture protection. "This tyre has 50% greater puncture protection" (than a condom used as a tyre).

 

[shadow master]

It is an easy claim to make since it is meaningless and difficult to prove or disprove. It reminds me of those beauty product adverts on TV - visibly reduces wrinkles (says 10 out of 27 women polled). What they don't tell you is that all the women in the poll were 16 years old.
The same goes for puncture protection. "This tyre has 50% greater puncture protection" (than a condom used as a tyre).

I agree I love those polls that take the best possible ratio of the number of people asked,when women are going to realise its your fingers massaging the skin that produces new cell growth and not the cream itself is beyond me! And guess what the cream you apply twice as much has better results.