JXB Performance Driveshaft Carrier - BMW15 - E85/E86/E89 - Street Bushings - BMW15A0-S
The stock center support bearing carrier holds the driveshaft in place with
a layer of thin rubber. 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 and ruin driveshaft alignment over time, and creates
slop in the driveline during shifts and throttle application.
Over time the OEM bushing 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 wears and sags, it changes the alignment of the
driveshaft, putting more stress on the joints. During rapid loading of the
driveshaft (launches, shifts, and quick application of the throttle), the
bearing is allowed to travel off-center, introducing slack in the
driveline, which results in laggy and unpredictable driveline response.
Our upgraded driveshaft carriers keep the driveshaft firmly in place at all
times. The more solid bushings ensure the bearing cannot move from center,
maintaining torque delivery and driveshaft alignment at all times,
resulting in more direct driveline response under all conditions.
Benefits as described by our customers include:
More direct throttle response
Firmer, more direct shifts
More instantaneous launches
Reduction in vibration due to driveshaft misalignment and/or rubber
deterioration
Smoother low-speed on/off throttle behavior (1st gear in parking lots)
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.
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.
The exact steps to access the carrier will vary slightly by model, but the
removal and installation of the new carrier are the same. The basic steps
are:
Remove any braces or splash shields preventing exhaust and heat shield
removal
Remove or lower exhaust in area of center support bearing if needed for
access
Remove heat shielding covering center support bearing
Cut off OEM carrier and remove rubber support material with razorblade,
leaving base layer of molded-on
rubber intact on the bearing
Clamp new carrier around OEM bearing
E85 and E86 Z4 and Z4 M Coupe/Roadster
E89 Z4
Street and Track refer to the durometer (stiffness) of the bushings. Track
are roughly twice the durometer of the street bushings. Both track and
street are many times stiffer than stock and will hold up to whatever abuse
are thrown at them, but the street bushings are better at soaking up
drivetrain noise and vibration. Usually both street and track are
completely silent and vibration-free, but in cases where there is an
underlying drivetrain issue causing the driveshaft to vibrate badly, the
track bushings may not be able to soak it all up, where the street bushings
can.
We generally recommend street bushings for any car that's not purpose-built
for track or overland use, since the street bushings have a much lower
chance of transmitting drivetrain NVH to the cabin at high speeds or under
heavy throttle loads.
If you’re not sure which to go with, the “Give me Both!” option will give
you a full set of each of the street and track bushings. You can use all
street, all track, or even mix and match them to find the perfect balance
of performance and NVH-absorption.
Street - BMW15A0-S
Track - BMW15A0-T
Both - BMW15A0-B
Street - BSH04A2
Track - BSH04A3
SHS01A4
