Stone chips from trucks: why the gap matters more than speed
Prevention
Nine out of ten chips we repair came from behind a truck. The physics is simple — and avoidable.
A stone thrown up by a truck's rear wheel travels at the sum of its speed and yours. At ninety km/h the impact energy is something a windscreen survives only if hit flat. Hit by an edge, you get a chip.
What decides is not your speed but your gap. The stone follows a ballistic path and loses height. At a two-second gap it hits the upper third, where glass is thickest. At half a second it lands right in your field of view — where repairs are not allowed.
Winter and spring are the worst, because grit stays on the shoulders and gets recycled back into the lane after the first heavy rain.
One more thing people underestimate: keep your distance when overtaking too. Most damage we see on the left side of the glass happened as the driver merged back in just ahead of a truck's rear axle.
If you already have a chip, count in days, not months. Fresh damage takes no dirt or water and the repair is almost invisible.
Got damage on your glass right now?
Send us a photo — we assess it free of charge and tell you whether a repair will do. Chip repairs need no appointment.
Write to us 0915 276 235Back to advice
