Here are some tips and mythbusting on the subject of frame sliders -- those little plastic, aluminum, or carbon fiber bobbins you sometimes see protruding out of a sportbike's side fairings.

1. Most are not intended to protect bodywork
Despite popular belief and even the marketing efforts of some parts distributors, the main function of frame sliders is to protect the motorcycle's frame in the event of a crash, not its bodywork. Thus the name, frame sliders. This reasoning is based in the fact that it takes very little frame damage to total a sportbike. With their space-age alloy frames, which many times cannot be heated or beaten during the repair process, the only viable option in some cases is simply to replace the entire piece. The inherent costs associated with frame replacement usually result in the bike being totaled by the insurance adjuster.

2. Frame sliders that bolt into small bodywork fasteners usually fail in a crash
I found this out the hard way, when I lowsided my ZX6R last year. As I picked myself up and walked toward the Red Sled, I began to notice that the frame protector had broken off at the bolt. My sweet, crimson mistress lay pitifully on her side, her lower right fairing cheesed beyond repair.

Any frame slider set you buy should have heavy-duty bolts (i.e., titanium) that replace load-bearing bolts such as those found at a motor mount. Otherwise, you're pretty much wasting your money in my opinion. A small-diameter bodywork bolt usually won't support the bike's weight and the other dynamic forces placed upon it, save for perhaps just a simple fall from a standstill.

3. Don't bother with fancy materials -- plastic works just fine
Why spend the extra money for milled amluminum or carbon fiber when the bobbin itself is a disposable object whose job is to destroy itself in a crash? Many AMA, WSB, and MotoGP teams use simple plastic bobbins, and I tend to agree with that practice. Anything else is little more than excessive bling. Here's why: