Problems with Factory Mounts
The factory BMW RTABs (Rear Trailing Arm Bushings) are a very soft material to provide the quietest, most comfortable ride possible. Because of this, we have seen factory mounts require replacement in less than 50,000 miles and 3 years. On modified vehicles, expect them to require replacement sooner.
Are your bushings already shot?
A simple test to determine if the stock rear trailing arm bushings require replacement is driving the vehicle in a straight line. While in gear, under full acceleration, does the car pull to one side? Additionally, under full, firm application of the brakes, does the car pull again? If you answered yes to either one, the bushings probably require replacement.
Rogue Engineering Performance RTABs
A common question asked is the true difference between our bushings and OE style rubber ones. It's not just material differences. It's the design differences that play a big role.
When the OE bushing is installed (or replaced correctly), it is under constant load when it is on the ground. In other words, the center of the bushing always remains "twisted". Some very sensitive people say they can actually feel the "spring" of the trailing arm when the rear of the car is loaded and unloaded (with the gas pedal, or setting up into a corner). Then again, these people could probably hear a mouse fart from 10 miles away. Most people can barely tell when bushing is cracked, let alone entirely broken.
The Rogue Engineering Performance RTAB differs greatly than the OE since the bushing is NEVER under load when the trailing arm is in any position. This means that the center of the bushing (the aluminum sleeve) pivots freely at all times. This means that it also lasts a long time. This also means consistent performance and not performance that degrades over time.
The bushing material used in Rogue Engineering Performance RTABs are now available in two different compounds, specifically for your needs. Both compounds now incorporate a silicone impregnated, polyurethane compound. The biggest different being the hardness of the material.
|BLACK||This compound is formulated for STREET applications. Softer than our blue, TRACK compound, these are stiffer than stock factory OEM bushings and designed to last much longer than stock. Since these are the great compromise between OEM and our TRACK bushing. Engineered to approximately Shore A 93 hardness.|
This harder compound is designed for TRACK applications, where monoball components are not allowed. These bushings are extremely stiff to provide the absolute maximum performance at the TRACK. Purposefully engineered to approximately Shore D 65 hardness. Just because you take your car to the track a few times a year does NOT mean you need these bushings. If you have a cage, and you trailer your car to the track, then these are the bushings for you.
This hardness is important in this bushing especially in modified vehicles, since they will exert more force on the rear suspension during acceleration.
The inner sleeve that supports the bushings is made from 6061-T6 aluminum, CNC'd to exacting specifications for a perfect fit, here in the good 'ole USA.
Do NOT confuse these bushings with bushings produced outside of the US, with unknown material with questionable hardness. We have installed similar bushings produced by other companies which are simply too soft. In these cases, it would have been better if stock bushings were used since it allows too much movement of the rear trailing arm.
Which bushing is best for you?
|Desired Performance||Recommended Product||Pros||Cons|
handling & ride
|Factory OEM RTAB||Just like stock||No performance gain|
|Improved handling, factory ride||RE Shims with OEM RTAB||Quiet||Very small handling improvement|
|Performance handling, firmer ride||RE RTAB BLACK||Slightly stiffer and longer lasting than OEM||More expensive than OEM|
|Ultimate handling, firm ride||RE RTAB BLUE||Long lasting, ultimate performance||Not as quiet and soft as stock|
|Maximum Performance||Monoball RTAB||No flex, race car performance||Can transmit|
Squeak, Squeak. What was that noise?
Our US manufacturer has has offered us a silicon based formula, to also keep the urethane bushings quiet during use. Approximately 1.3 oz. of silicon is poured into the mold, which means that it is permanently impregnated into each bushing. This process costs more to produce, but we feel that it makes for a better product in the long run.
A common downside of the urethane bushings over stock rubber ones was that they would typically develop noise over time (or even right away). These noises were from a combination of the harder material, inadequate lubrication (or none at all), and the contact with the factory steel mounting hat rubbing against the bushing.
Professional Installation Required
Because the RTAB "console" removal is required, an alignment is recommended. For installation of the part itself, it is very straightforward, but requires some special tools. We recommend grease that has PTFE in it. A favorite in our shop is SuperLube.
Fits the following vehicles:
- All E36, including M3. Does NOT fit Z3 and 318ti.
- All E46, including M3.
- All Z4