JC3D

During my cars diet, if I am not meeting the minimum weight, I may need to go with lexan windows for the rear and rear sides. For the rear window installation, does it require and sort of bracing for the middle of it? and if so, where do I go about buying something like that?

Geoffrey

You will need some type of bracing on the rear window. At speed, it will tend to push into the cockpit due to the air pressure over the top of the car.

smlporsche

I think it depends on the thickness of the lexan.
On the thinner ones you will need some bracing but on the thicker (3/16"?) you don't.
At least I don't...

JC3D

Is this bracing something that I have to make? or do they sell it somewhere?

JC3D

Also, I have seen racingshields and other companies that are selling lexan windows with all of the coatings on them. Is this really necessary? Is it bad to just buy them uncoated?

genikz

I would look into tear-offs in lieu of coatings, personally. You can replace the tear-off when it gets ratty and apply another one.

Like a screen protector for your cell phone screen...

I can't recall who sells them though.

Geoffrey

on the windows you specify, I would get a polycarbonate that has an antiscratch coating.

onefastviking

Tearoffs are not that cheap.

genikz

Agreed. When I was looking into that option, the best price I could find was $85 per sheet. But if it lasts a season, and leaves you with a new(ish) lexan windshield underneath, then it's a solid option in my book.

JackOlsen

The need for rear supports depends on how you do the mounting. I have pretty thin Lexan, but it's in a flush-fit frame. I've never had issues with it flexing or burping. (As a point of reference, my fiberglass hood burps in when I'm up in the triple digits.)

GT3CAR

my rear window (lexan window from PMNA) pops at speed. I need to put bracing on it one day. Installing side windows is a good project that requires the removal of the coverings surrounding the stock seat belt mounting point for the shoulder belt so that you can access the two bolts.

amondc

Cheaper then new windshields though. We put a 4 layer on our 04 car when we got it new. We just took off the first layer and the windshield looks new again. I think the tear-off were $400 or so but they were on for 4 years before we removed one layer. Still have 3 more to go so over 12yrs $400 isnt so bad.

kurt M

If you can get hard coated polycarbonate do so IMO. An entire windscreen, hard coated both sides was about $500. First plastic windscreen for me but I have extensive time spent working with Lexan (polycarbonate) both machining and thermoforming. It scratches very easily. Tear offs only protect the outside surface and only where they cover. The inside surface and will get scratched up even when cleaning with proper cloths and cleaners. Just running a finger across it leaves micro scratches that show up in cross light and add up over time. Polycarbonate is attacked by many hydrocarbon based chemicals. Most of the coatings help protect it from crazing and weakening too. Polycarbonate will take a sledgehammer hit in good condition but crack in your hands after being degraded by relatively short contact time with Brake Kleen or over longer contact times motor oil and the like. This is most noted where the surface is stressed as in around fastners.
I plan on adding an under $100 2 layer tear off set on the outside after milling and installing the plastic.

JackOlsen

My front windshield and roll-ups are the only glass on my car.

As a point of reference, my last windshield was $120, installed. Glass is heavy, but it's also a bargain.

I guess there's no news flash to it: speed is expensive.

Bryan Watts

If you buy a properly curved piece of rear poly rather than just installing a flat piece, you may not need any interior bracing. Think of the egg shell example from middle school science class. That said, some groups do require exterior bracing to prevent rear window blowouts...just check the rules for your class.