Vorshlag Limiters for Rear Trailing Arm Bushing (Full Set)

The RTAB Limiters include 4 pieces of limiters good enough for 2 RTABs

Optional:

Pair of Lemforder (OEM) RTABS = $38.95

This product entry is for a pair of OEM replacement Rear Trailing Arm Bushings for a BMW E36 (except ti/Z3), E46 chassis or Z4. This kit is enough to replace both of the factory rear trailing arm bushings on any of these cars.

These bushings are the latest "split-case" design that BMW recommends for all Z4M and M3 models, based on the latest Z4M RTAB bushing. It will also work very well in the non-M E36/46, with BMW part number 33326770786, better than the original bushings for these cars. There is no void ratio, and it uses a firmer durometer rubber. These will not affect ride comfort and allow the rear suspension fully articulate without bind, unlike other replacement options out there.

In the Rear Trailing Arm Bushing (RTAB) location on the rear suspension of an E36 or E46 BMW the bushing has to pivot on two axis. Unlike other suspension bushing locations that only have one axis of rotation, swapping in excessively stiff replacement bushings using materials such as Delrin or Polyurethane can and will cause suspension bind. This replacement rubber Z4M bushing is compliant and effective when brand new but can still wear out over time. We highly recommend replacing them in any E36 or E46 BMW you purchase that has more than 20K miles, and we also strongly recommend using them with our RTAB Limiter Kit, which can be bundled with these bushings in the options below. If your stock RTABs have more than 20K miles and/or you've used the car for more than a season of racing, they are likely shot.

Many racers just blindly install polyurethane into this and all bushing locations as a "fix" for a worn OEM rubber RTAB bushing. Polyurethane is a bad choice for a bushing material if it has to deflect - such as in a multi-axis suspension bushing location like the RTAB. Rubber bushings + limiters or a complete replacement with a custom steel spherical bearing are the only two textbook choices for this location. We cannot count the number of times we have seen RTAB or front LCA failures on BMWs that were using poly in these areas - an expensive repair and a dangerous racing situation. At the very least poly will add bind during significant suspension movement, and this can make the handling feel odd (unexplained oversteer) as well as add significant stress to the suspension-to-chassis mounts (which is how they can fail over time).

That said, some folks with fully track prepared race BMWs have had OK results with polyurethane RTABs. This is due to the much higher spring rates and smoothness of tracks they tend to run with - higher spring rates and smooth tracks limit suspension travel, and thus limits the potential for bind from a polyurethane bushing at this bushing location. So even though you may hear good results from one racer, it doesn't necessarily mean that poly RTABs are the right choice for you. If you have a street car or dual purpose BMW you should always stick with OEM bushings and RTAB limiters, and even many race prepped BMWs use this setup with excellent results.

These are a "set and forget" item - install this set of factory RTAB bushings with our Limiters and they should be good for many tens of thousands of trouble free street and track miles. Instructions for RTAB Limiter installation are found on Vorshlag's Instructions page. Installation instructions of the RTAB bushings themselves can be found in your Bently service manual. There are  tools available to help make the RTAB installaiton easier.