Tie-down straps come in two flavors-ratchet or cam buckle-style. Cam buckles use friction created by the strap as it passes through a spring-loaded, cam-shaped buckle to hold the strap in place. Ratchet straps operate in much the same manner, but with a ratchet buckle to progressively tighten the strap. Both allow you to secure the bike yourself and bump up tension on the suspension to reduce shock loading. Shock loading occurs when the vehicle hauling your bike hits a bump in the road, causing the bike's suspension to compress. When the suspension compresses, the straps go slack, but as it rebounds, the tie-downs snap taut again-which can eventually loosen or break them. The more you load the suspension during tie-down, the less it will compress during towing. Some folks claim that ratchet straps are more effective at maximizing compression, but Candreia says he's comfortable with the cams because they're easier to work with.