4 Symptoms of Failing Trailing Arm Bushings

Many of BMW’s most iconic models feature an independent rear suspension that utilizes a trailing arm. Trailing arms are a suspension piece that connects the rear hub to a mounting point on the body/frame using a bushing as a pivot point. This bushing is referred to as a rear trailing arm bushing, or RTAB for short. At the BMW factory, the control arm bushings that are installed feature metal and rubber components that are subject to a lot of pressure and movement. BMW used rubber to provide the most comfort possible for everyday driving conditions. As a result, these bushings will wear out over time and will need replacement. Read on about several of the symptoms that point towards failing or failed trailing arm bushings.

1. Strange Noises

Strange noises coming from underneath your car are probably the most common symptoms of failed trailing arm bushings. The design of a factory-installed bushing allows for movement under stress and pressure, and the rubber keeps things quiet. As the rubber portion of the bushing ages and starts to deteriorate and fail, the metal parts come into contact with each other, and a clunking noise will start to develop. This is a symptom that is only noticeable while a car is in motion, especially under cornering. If you hear any knocking noise coming from under your BMW, check it out and get it fixed. Safety should be your top priority on the street or the track! 

2. Tire Wear

Excessive or uneven tire wear is another symptom of failed trailing arm bushings. These bushings play a significant role in the rear suspension of a BMW, and when they fail, they can affect and add strain to many of the parts involved, especially tires. As the rubber portion of your control arm bushing fails, your car’s alignment can change gradually over time or suddenly if your bushings fail entirely. For street and track applications, proper wheel alignment is crucial, and the wrong setup will destroy a set of tires on short notice. Tire inspections should happen on a regular basis, and every car from a daily driver to a track warrior should be inspected often, so alignment issues due to failed trailing arm bushings should be easy to catch.

3. Poor Handling

Poor handling can be a symptom of many things, but failed trailing arm bushings are a likely culprit. The rear trailing bushings on a BMW are meant to move in multiple directions. This means that they are not only put under more stress than a lot of suspension components, but it also means that when they fail, they will affect multiple other parts of the car. If your bushings are bad enough, it can cause the rear suspension parts to move from side to side while driving in a way that will mimic a steering issue. In this case, you might feel some looseness or slack in your car's steering wheel, but you are having to overcorrect for movement due to failed trailing arm bushings. If your steering system components look good, check out those trailing arm bushings! 

4. Other Failed Bushings

Many drivers only replace their trailing arm bushings when they have failed completely, but there are other good reasons to replace them. One of the best reasons to replace these bushings is if you are already replacing other rear suspension bushings. Most of these other bushings also utilize rubber components that will fail and need to be replaced and replacing them all at one time will save on time and money. Replacing your bushings one or two at a time on separate occasions can eat some serious time off the clock, so while you have it apart, replace all that you can. BMW performance and racing parts can often be purchased at a discount if bought as part of a parts combo from a reputable site like Condor Speed Shop, so if you are doing a lot of work on your rear suspension system, it makes financial sense to go with a combo.  

Time for New Bushings

If your car is experiencing any of these symptoms, check your rear trailing arm bushings and see if they are wearing and starting to fail or have whipped out completely. If they have, it is time to replace them. There are several options currently available. Factory rubber bushings are the most comfortable choice, but they will not hold up on track, and the rubber portion will eventually fail again. Performance-minded drivers might prefer to install our Delrin RTAB Limiters and run them in conjunction with the factory bushings. They will keep everything firmly in place without any additional harshness. The best choice for anyone who plans on using their BMW on the street and track is to replace your old bushings with new RTABs made from ultra-high-molecular-weight polyethylene (UHMW). The material allows for the bushings to last longer than other urethane and rubber examples, and they will provide a better experience for performance-minded drivers. If you want to go all out, you’ll want to replace your rear trailing arm bushings with our monoball version. They are the best rear trailing arm monoball bearing on the market. While at home on the street, this bearing is designed for track duty. 

Symptoms of Catching the Racing Bug

Wanting to hit the track? Getting the urge to race is the best possible reason to replace your old and worn bushings. Whether you are headed to your local autocross or entering a twice-around-the-clock endurance race, you will want to upgrade your trailing arm bushings. We have a variety of options, and our best all-around bushings are the UHMW versions. These UHMW bushings will aid in a suspension’s stiffness by having almost zero deflection, but also the ability to absorb some vibration, making them a must-have for a track car traveling at higher speeds. The best bushings available for BMW motorsport applications can be found at Condor Speed Shop and are a must-have if you plan on any performance driving. Their replacement bushings are made of the best material possible and feature black oxide plated steel plates which help prevent lateral movement between the bushing material and the aluminum insert which make up the bushing. The tighter feel and better car control provided by upgraded trailing arm bushings will give you a competitive edge on track.  

Bushings Replacement

The trailing arm bushings on your BMW will eventually have to be replaced, either because the factory bushings have failed due to age and stress or because you are looking for a performance upgrade. This is a job that can be completed by any knowledgeable and competent BMW enthusiast. Condor Speed Shop not only has the best bushings available either by themselves or a part of a parts combo, but we also sell and rent specialty tools used to complete the job. If you decide to let your favorite independent BMW repair shop replace your bushings, just be sure that they use the best products available and go with track-tested parts from Condor Speed Shop. If you see any of the common signs of failing trailing arm bushings, Condor Speed Shop has the cure!