Mass+Velocity=Crack

[shatto]

I drives a lot.
A bunch of stuff has hit the windscreen.

Everything from bugs to sand to rocks has a unique sound, that changes with the impact point on the glass and the speed I'm driving.
Sometimes the whap! of a bug will make me flinch

Some pieces make a cracking sound to a soft thud. Some, I imagine are like a marble would sound.
A rock that looks the size of a baseball coming at me but is really less than an inch across may leave an ugly dirt mark that, when wiped away leaves only a tiny pock-mark.

Then there was Thursday....
Never saw the culprit, just heard a metallic 'ping' sound that caught my attention just because it was so unusual.
Later, when the light was just so....a crack sprouting straight up from the very bottom of the windshield.

Reflecting on the experience,
I wonder if the combination of the strike location as well as the density and speed of the rock combined to set up a harmonic that cracked the glass.

[VetteOwner]

what lol prolly just chipped the glass good and crack just got bigger.

i do remember my mom once washing one of our cars and hit the cold hose water on the windshield with the hot interior and a huge crack imediately sprang up from a rock chip haha

[JanGeo]

High speed = heavy loads on glass. Stick your hand out the window at 60-80 mph and then imagine the load on the windshield. One small chip in the right spot under high speed will flex the glass and snap it in two pieces just like a scratch on a plate glass pane.

[GasSavers_JoeBob]

Originally Posted by JanGeo

High speed = heavy loads on glass. Stick your hand out the window at 60-80 mph and then imagine the load on the windshield. One small chip in the right spot under high speed will flex the glass and snap it in two pieces just like a scratch on a plate glass pane.

Ahhh...a clue as to why every cracked windshield I've encountered happened while on the freeway...

I've heard of rare instances where tempered glass (side or rear windows, not windshield) can just spontaneously shatter. I was too small to remember this, but that is supposedly what happened to our Goliath microbus one time (no one saw anyone throw a rock at it, anyway...)

[bowtieguy]

yup, that really bites. i'd suspect most of us here don't have full coverage and as a result have to pay cash for a new windshield.

[theholycow]

I have full coverage but my deductible is higher than the cost for a windshield.

[shatto]

Originally Posted by theholycow

I have full coverage but my deductible is higher than the cost for a windshield.

If your insurance company does not offer a glass rider.......
May I suggest Farmers Insurance.
I am sure there are others.

[JanGeo]

What's worse is I just got my insurance renewal and lost my 3 years without an accident discount from Progressive when I got hit from behind while stopped in a parking lot . . . going to cost me extra for 3 years or about $250 extra total.

[GasSavers_Pete]

Could also be stresses built up in the glass suddenly released by a small stone causing the crack and the odd noise.

Just thinking out loud here.

Pete.

[VetteOwner]

Originally Posted by bowtieguy

yup, that really bites. i'd suspect most of us here don't have full coverage and as a result have to pay cash for a new windshield.

yea usually a new windshield is around 2-300 (depends on the car id suppose)

i think my deductable is 5-600

or do what we do, if its only a single crack screw it lol. weve driven cars for years with cracked windshields