--Just FYI from a rider, there is some conflicting information out there:
https://rideapart.com/articles...
> Every helmet maker ever will tell you not to apply Rain-X or something similar to your visor. However, weâ(TM)ve been doing it for years with no ill effects. It causes water to quickly bead up and run off, aiding vision. Itâ(TM)s said to reduce the effective life of your shield, but weâ(TM)re replacing our clear visors once a year anyway due to scratches and whatnot. So itâ(TM)s definitely worth considering if youâ(TM)re regularly riding in wet road conditions.
http://www.triumphrat.net/spri...
> First, what is Rain-X and why is it a problem for visors? Itâ(TM)s a mixture of ethanol, acetone and isopropyl alcohol with a bit of silicone thrown it. Those three solventsâ"quite aggressiveâ"super clean the surface and leave behind a molecular layer of silicone that causes water to bead and shed. The product was originally intended for glass windshields and the company that currently owns the trademarkâ"ITW Brandsâ"says it is not recommend for plastic. The problem material is the acetone, which can soften and craze acrylics and polycarbonates.
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>> The best reason not to use Rain-X is that there are better cleaner/rain-repellant products, specifically paste-type cleaners that are basically emulsifiers with a little isopropyl alcohol thrown in as a solvent and silicone or wax to act as surfactants, causing water to bead and blow off. I tested a half dozen of these and the two best were LP Acrylic Polish and Sealant and 210 Plastic Scratch Remover. Others, such as Plexus, perform similarly.