Rebuildable flex joints are also available in weld-on versions for those looking to make their own links. Most have replaceable synthetic race inserts and some threaded means of preload adjustment. These joints are often larger than equivalent rod ends so usually require greater mounting area for use. However, with their races made from non-metallic material, they transmit less noise through the suspension links into the chassis than a rod end would. In some suspensions, it’s possible to use a firm rubber or urethane bushing at on link end and a spherical flex joint at the other end to get some benefits from both joint materials.