Get Faster Track Times Replace soft suspension rubber with plastic helps. But it is far from ideal for the serious competitor, and some find the occasional bushing squeak annoying. Now we have a better idea. ERP/Weltmeister® Monoball Cartridges positively locate the suspension arms so suspension motion is accurately repeated in every corner, without the wallow of rubber. These cartridges have contributed to race wins at Daytona, Sebring and European tracks. Now the time and money you spend aligning your suspension will pay off in improved feedback, quicker track time. Crafted in high carbon steel and 7075 T6 aircraft aluminum, ERP/Weltmeister® monoball cartridges are the ultimate upgrade. Note: may resonate noise during street driving Learn More