Ever heard of this?

[Trek420]

My LBS (Hi Chris!) says "The device she speaks of was called a " Tire saver " mounted to the brake caliper using a spring piece of wire (generally made from a bicycle spoke) to constantly brush the tire tread in hope of dislodging glass slivers and the like before they could penetrate all the way to the inner tube."

Yes they work, yes I've seen them before though not so much now.

But they work, and don't drag on the tire. And they look cool too. My LBS has a customer who is a mechanical engineer, he custom makes these. So if anyone here wants one I can put you in touch.

Of course you can always brush the tire with your glove from time to time or when you suspect you went over glass. I've seen riders who can even sweep clear the rear tire in motion.

I tried that once, it's why folks call me Trek-old geezer with 8 fingers-420