12 Excessive twist can be a problem when spherical bearings (in the form of uniballs or rod ends) are used on both ends of a trailing arm. There are a few ways to counteract this negative trait. One is to use a wobble-stopper uniball at the frame end of the link. The wobble stopper is simply a uniball assembly that features an external twist limiter, usually in the form of a custom-machined spacer made from nylon or Delrin. Blitzkrieg Motorsports and Kartek Off-Road both offer wobble-stopper uniball assemblies as stand-alone builder parts.