After many requests, we are proud to introduce our own E36/E46 Monoball Rear Trailing Arm Bushing (RTAB). Why would we introduce an item like this to the market, after so many years...and so many versions already out there? This replaces the OEM #33-32-6-770-817.
Sizing up the Competition
As mentioned, there are lots of others out there whom sell similar product. So in order for us to come up with our own version, we had to evaluate what we wanted from our own design.
- Price point. Currently available monoball RTABs range in price from $180 all the way up to $573. Whatever we decided to develop, we had to be within these parameters.
- What is "monoball"? When this term is used, two different options can be used. There is a rubber-sealed style and spherical bearing version. For our design, we decided on the spherical bearing version in our design (which we will discuss below).
- Usage. We wanted to eliminate the inherent deflection of the stock rubber bushings for those looking for the most precision from their suspension. These are typically drivers who demand the most of their cars such as people that do canyon runs, HPDEs and racers. This also reduces brake shimmy and improves steering responsiveness. For people looking for a cushy, OEM ride, look to our urethane versions.
- Precision alignment. Our included parts allow for either specific alignment specs for the road or even extreme specs (such as drifting and zero toe requirements). Our RTABs come with two different pairs of spacers to achieve this. Since we utilize the specific spherical bearing, it gives us this flexibility. Those that use rubber-sealed style bushings in this application cannot do this.
- Serviceability. By using extra-wide spherical bearings (15% wider than bearings in the same size), we can support more load in a similar space used by others. Replacements are commonly available through companies that sell replacement bearings, given the part number.
- Installation issues. Installation of this style of RTAB was a point of contention. We ourselves have installed many other aftermarket, monoball RTABs in our shop and we have definitely cursed up a storm getting them in. Whatever we designed, we wanted it to be installer-friendly so we do not lose friends in the process.
Difference in "Monoballs"
To understand what companies refer to as "monoball", here is a quick tutorial on the two types of monoballs used in bushings.
- Sealed Joint Assembly. These bearings have benefits such as rubber seals (retains grease while keeping out dirt) which makes these great for low maintenance. However, they can difficult to replace and frequently use plastic races for the main bearing joint. Typical removal typically means destroying the joint in its entirety with brute force.
- Spherical Bearings. These are have larger pivot joints (which can handle more load), use a metallic race (lined or unlined), and because it does not use plastic, is considered a precision component. They are not normally sealed, so inspection is easier. Maintenance is expected. Replacements are normally commonly available industry wide given the size.
One design feature of our RTAB was the ability to offset the bushing position (if required). A sealed joint assemblies are generally much wider than spherical bearings, we chose to use the spherical bearing for additional flexibility in our design.
Centered or Offset?
Included with the kit are two sets of spacers for different configurations. A quick explanation of the two positions;
- Centered. This is a "factory spec" where the bushing is in the middle, allowing for alignment adjustments near OEM.
- Offset. This is to position the bearing to the extremes, to alignment settings outside of normal parameters such as alignment for drifting or for correction of suspension.
An instance where the offset option can prove to be helpful (at the track) is when damage to the trailing arm has occurred. Since the factory trailing arm is cast steel, when it takes a hit, it can bend without even being noticed. Usually this becomes apparent when an alignment is performed. Usually the deformation means that the toe setting cannot be adjusted to match the other side, because it has reached its limit range. By using the offset spacers, you can gain additional range to get the alignment back to where it needs to be for the remainder of the event. This is nor a permanent fix, of course, as it would be recommended to replace the damaged component when possible.
Rogue Engineering Monoball RTAB features;
- 6061-T6 ACQ CNC'd construction, anodized
- FK Bearing, extra-wide, extra-load, precision spherical bearings (13% wider than a bearing of the same size)
- Two sets of bearing spacers; One set for "centered" bearing alignment and one set for "offset" alignment, depending on customer requirements
Sold as a pair.
Fits the following vehicles;
- All E36 (not Ti)
- All E46
- All Z4
