Originally Posted by
HerrKaLeun
The physics are the same, air diffuses under the cup over time. There is no 100% airtight material, the molecules are just too small and the gaps between atoms too large.
Many people leave racks on the car for longer. And checking the rack before every drive is just not what people do. Heck, people are supposed to check engine oil, light and other things and never do. A bike rack should just be solidly attached without the need to re-tighten.
IMHO, a hitch rack with platforms is the very best solution. Everything else has some shortcomings.
They're not perfect either. Depending on the vehicle they can greatly impact rear visibility on say a sedan or smaller hatchback. I don't keep my Kuat rack on my hybrid, because even in empty-and-stowed configuration it obstructs my backup camera--which on that vehicle I really need as the rear visibility is poor. There's also the matter of blocking your rear license tags from LEO view, which I've known people to get pulled over for (but not ticketed, at least yet).