Tech articles ST185 Buyer's guide [New] What do you need to look out for when buying an ancient GT-Four ST185 (Carlos Sainz)? In this article I try to cover the important things. Several points on the list are easy to check and by doing so, you might be able to save yourself time and money in the long run. 54.1 vs 55.0 mm The center bore difference could cause trouble when using ST205 rear brakes on a ST185. Here's an easy way to fix it. A visit to AP Racing After my big brake kit was ready for fitment, I went to the AP Racing headquarters in Coventry, UK. Besides the installation of the first ever ST185 Formula big brake kit on my car, I was given an exclusive view behind the scenes. The search for proper stoppers An article about my quest for a high quality ST185 big brake kit and a personal opinion on what's available at the moment.