A 3-dimensional triangular rim is used by other observation wheels, while Singapore Flyer uses a slim ladder truss rim, a technological revolution.By using a wider hub to create more acute cable angles, there is greater efficiency in resisting lateral loads and providing the rim for buckling in compression. Cables are used to attach the rim to the spindle. Usually, massive steel structures are used to support the rim. - See more at: http://www.singaporeflyer.com/about-us/observation-vs-ferris-wheels/#sthash.GdhYHqwa.dpuf