- The offending flint
Should you check your tyres for embedded flints and pick them out, or leave well alone? It probably depends on whether or not you believe a flint left in the tyre will eventually penetrate it and puncture the tube. After all, if this is not what happens, why bother? (No, DA, the weight of the flints is not significant)
This is one argument that should not be too hard to resolve: check tyres until a suitable flint is found embedded, then leave it there for a few hundred miles or until the tyre flats.
Even we can manage that. The result was a win for the idle, since not only did the flint not penetrate the tyre, but it developed a smoothed road-side edge that indicated it was being worn away by the road surface with every revolution.
This is not unimportant. The argument essentially revolves around the question of whether a flint gradually works its way through a tyre, driven by the pressure repeatedly exerted on it by the road surface, or whether a flint gets just one chance, on initial contact, to do the foul deed.
- Flint embedded in tyre tread
Having over the years found many flints in tyres worn enough for replacement, I had previously concluded that the latter is correct. This experiment would seem to confirm the view. In other words, if the flint is not long enough to pierce the tyre completely on first contact, it simply sits in the tread and goes in no further.
Repeated contact between the tread at the point where the flint is lodged and the road do not drive it in because the tread does not get sufficiently thin as it compresses against the Tarmac. The mechanism that prevents it working in over time is the steady erosion of the back of the flint by the road, so that as the tread gets thinner, the flint gets shorter.
That’s my theory, anyway.
- Flint extracted; note rounded edge
phil parker says:
Yes, I always pick out the flints and there’s no shortage of them in Wiltshire, they’ve been the cause of more of my punctures than anything else!
JulesW says:
One of my friends always lifts them out then uses a dab od superglue to reseal the cut. (He is a very tidy person).
And always remember that you get more tyres on wet roads. My old cycling club used to say that water ‘lifts’ the sharps from the tarmac. But a Xmas lecture program showed that wet rubber is easier to cut. Try this with a rubber band – cut with pair of scissors, then repeat after wetting the band first. Simples!
tullio says:
what do people find best for the resulting hole?
nothing/superglue/shoe goo
never had much success with the latter
Simon Trickett 3 says:
i use a rubberised superglue
http://tinyurl.com/3rgq8he
John Hardy says:
What does ‘flints’ cover? Just stone? Presumably if you get a stone with a very sharp point or ridge on the inner tube side, it might well work through. Glass or thorns would presumably work through, even if they don’t on the first contact.
Also, does this article assume that the tyre has an at least fairly decent puncture protection belt?
Personally I believe it’s probably best to be on the safe side and if you find anything at all, flint, glass, thorn or anything else, take it out and superglue the hole.
Mich O says:
Agree with John Hardy. It’s not “flints” that are the problem, it’s broken glass. The little shards ALWAYS work their way in and eventually puncture the tube.
Whenever I’ve got a wheel off, I always check the tyre for glass and dig the damned stuff out when found.
Another problem is thorns. I’d like to shoot vermin farmers who cut their hedgerows with a tractor which has one of those big trimmers attached.