THE PROBLEM
The stock center support bearing carrier holds the driveshaft in place with rubber so thin about 20 lbs of force moves it from center to the end of its travel. While that???s great for making sure no NVH makes it to the cabin, it doesn???t keep the bearing centered well under load, allows the bearing to sag over time and ruin the driveshaft alignment, and creates slop in the driveline during shifts and throttle application. Over time the OEM bushing sags and becomes brittle, eventually dry rotting and cracking. Even on the best-kept cars, the stock bushing can start to form cracks in as little as 5-10 years. When the bushing lets go, it can lead to excessive vibration and clunking and puts more stress on the bearing. To make matters worse, the stock carrier is molded onto the center support bearing, so it???s not easy to replace without special tools.
The first video below was recorded on an Audi, but BMW (and everyone else???s) OEM carrier design is similar. The shaft is not well-supported by the soft OEM carrier, so it???s allowed to travel off-center during rapid loading and unloading. The second video is a BMW carrier showing a comparison of how much the OEM carrier gives under load and the improvement with the JXB carrier.
THE SOLUTION
This upgraded unit keeps the driveshaft firmly in place at all times, and its solid construction ensures it will never wear out. The thick bushings ensure the driveshaft cannot move from center, maintaining driveshaft alignment at all times.
THE BUSHINGS
Two options are available for the bushings, both of which are many times over better than the stock bushing. We???ve paid close attention to the NVH levels associated with this upgrade. After extensive design iterations, we???ve come up with custom isolator bushings that separate the carrier from the body of the vehicle and mounting hardware. These carriers substantially reduce NVH levels.
The street bushings absorb most of the NVH from the drivetrain. Some light NVH is possible at some speeds in the form of a soft hum. With a modified exhaust or windows down you???ll probably never hear it.
The track bushings are for those who want no-compromise drivetrain performance. These may create a substantial amount of cabin noise. Not sure which is for you? They???re interchangeable so you can try them both.
INSTALLATION
Installation doesn???t require removal of the driveshaft. The 2-part design clamps around the OEM bearing. The old carrier must be removed, so a cutting tool is required.
FITMENT
E85 and E86 Z4 and Z4 M Coupe/Roadster
E89 Z4
Part Numbers
Full Assemblies
Street - BMW15A0-S
Track - BMW15A0-T
Both - BMW15A0-B
Spare Bushing Packs
Street - BSH04A2
Track - BSH04A3
