hey guys im still learning some things about racing but i was browsing a site and saw some things about lexan windows. how are they better than normal windows? i figure they probably dont shatter like glass. but is it lighter. and why dont people use them on normal street cars?

 

Lexan is not safety glass, it will be nearly impossible for you to break them out if you need to exit the vehicle after a crash.

They are designed to keep you in the car for race applications. Unless you are in a completely race prepped car, I wouldn't bother.

Lexan is also easier to scratch.

Cheers!

 

And Lexan is VERY expensive.

 

Actually Cheaper than glass but WILL put you into different classes.

Here in AU you are NOT allowed to use it for Drivers side but all other are OK for use.
You can Insert defrosters into the windscreen for added vision , but NOT road legal anywhere that I know

 

You are correct. Lexan does not shatter.

Lexan has a low modulus of elasticity and is much less stiff than glass. For the equivalent weight of lexan and glass, glass will be much stiffer.

However, it has a much higher impact strength than glass.

People don't use them on normal street cars because of a few reasons:

1) As mentioned before, it's nearly impossible to "break" lexan, which means that traditional methods of emergency egress/ingress are ineffective.
2) Lexan has a very low hardness. This means that it will scratch very easily, much like the surface of an ipod. Over time, road dust, rocks, etc will turn lexan into a hazy mess. There is technology available to "coat" lexan with a high-hardness film, but this coating is not ready for mass production.
3) Lexan degrades in ultraviolet. A glass auto window may last for a thousand years in the sun without any degradation. A lexan window will yellow and become brittle in less than a decade. Films/coatings can reduce this effect but the UV resistance will never be as good as glass.
4) Lexan does not have the dimensional/temperature stability that glass has. Glass can easily withstand temperatures up to 400+ degrees without losing any of its physical properties. Lexan loses some of its physical properties at temperatures as low as 200 degrees fahrenheit, becoming weaker and/or more flexible.