Time for a follow-up to add something I neglected to write about in the first review.
We used those Spring Creek cradles on a 5000+ mile western road trip, with two sea kayaks loaded on the roof of a Chevy Tahoe. The kayaks stayed put very well without supertight strapping.
We only occasionally rooftop, preferring to use a trailer for most of our kayak transportation. But sometimes we cannot use the trailer (that trip was one of them). Today was another example; this paddling location prohibits trailered boats. The drive up includes a long, washboard dirt road switchbacking up (and then back down) mountain terrain. The kayaks did not move even an inch on any part of the drive, and their fiberglass hulls remained unmarked and undented. Again, we do not need to crank the straps supertight with these cradles. (We do use bow and stern painter lines.)
The long, thick, sticky rubber cradle pieces wrap partway up the sides of the hulls, giving gentle, flexible support.
I am so pleased with these cradles that I plan to order one more set to put on another vehicle's crossbars. Kudos to Spring Creek for making an excellent product. It is a shame that these are not more well-known to sea kayakers.Castle Craft sells these cradles, which are made by Spring Creek.
I consider these the best production cradles I've ever seen. This is the type of product that exemplifies "Made in America", and I'm no flag-waver.
The hardware is sturdy, thick aluminum. The cradles themselves are long flexible rubber pieces (like wide straps) that can wrap well up the sides of your kayak (depending how you set up the cradles). Nothing harsh touches the kayak, just that forgiving rubber.
The clamping pieces will fit standard round or square crossbars, plus some rectangular bars. In other words, you are not bound to using crossbars from "The Big Two." For hull-down cradles, I have yet to see anything better than the Spring Creek cradles, and I recommend them to anybody who needs to transport sea kayaks.