Use this tech guide to help navigate the rear control arms best for your Mustang. We cover everything from bushing type to adjustable v. non-adjustable control arms.
One of the first mods that you look at doing to your Mustang is replacing your control arms. Whether you are purchasing a new S550 Mustang off the showroom or purchasing a new-to-you Fox body Mustang GT, replacing the stock components for something more performance improved or replacing worn control arms with fresh control arms will be on your mind. Depending on the year model of your model year of your Mustang, the style of the rear suspension will vary. Below we will go over some offerings and recommendations on which control arms will best fit your rear-wheel drive Mustang and driving style.
The first thing you will want to consider when looking at replacement control arms will be how the car will be used. The bushing material and style of the control arm will be the biggest determining factor on which control arm you want to put on your Mustang. Use the guide below to help you select the best control arm for your application.
There are generally four types of bushings used in Mustang control arms, rubber, polyurethane, Delrin, and spherical. OEM control arms utilize rubber to prevent noise, harness, and vibration (NVH). Polyurethane bushings will provide a harder material (increased durometer) than the factory rubber, decreasing deflection. Deflection will be the ability for the material to not compress under load. Less deflection will result in keeping the rear axle in a neutral position preventing axle twitchiness during cornering or hopping during hard accelerations. The next step up from polyurethane will be Delrin. Delin is a polymer material that provides a hardness of metal with great low-friction and high wear resistance. Its increased harness further prevents deflection compared to rubber and polyurethane. Due to the hardness of Delrin, it can transmit more NVH than rubber and polyurethane, which means you may hear more suspension noises. Lastly, spherical bushings will be the most race-ready control arm bushing. Spherical bushings provide almost zero defection and the ability of the rear axle to manipulate with very little resistance.
Not always are we looking to make a Mustang a mean track duty Mustang. If you want to replace worn-out stock control arms or take-off performance control arms for factory restoration, Late Model Restoration has factory replacement control arms that will give your Mustang a refreshed control arm without providing additional noise, harnesses, and vibration (NVH). This will use stock durometer rubber bushings designed by Ford Motor Company and construction great for factory restoration projects where performance is not a priority.
Control arms utilizing urethane bushings greatly improve the stock rubber bushing control arms. Control arms with polyurethane control arms are great for the Mustang that will be used mainly as a daily driver but may see an occasional competition event. Polyurethane is great at dampening NVH but harder than the factory rubber, making it have less deflection, and providing better acceleration and handling characteristics.
Control arms utilizing Delrin will be a step up from the polyurethane versions. Delrin is a harder material than polyurethane making it less prone to deflection, which will mean better performance. These control arms are great for a strip car that might see some street duty from time to time.
Spherical bushings will be the ultimate control arm for someone looking to get the best lap times in their Mustang. Spherical bushings are generally designed for Mustangs that will be used in road racing, autocross, and drag racing environments. While some people will opt to use them in a serious horsepower street-strip Mustang, they will transmit excessive NVH into the cabin and can be extremely noisy compared to Delrin, polyurethane, and rubber.
|Wheel Hop Reduction||Most Wheel Hop||Reduced Wheel Hop||Reduced Wheel Hop||Least Wheel Hop|
|NVH Reduction||Least NVH||Moderate NVH||Moderate NVH||Most NVH|
|Best Driving Style||Daily Driving||Mix of street & some race||Mix of race & some street||Race|
Once you decide on which upper and rear lower control arm bushing you want to use on your suspension, the next choice will be whether you want to run an adjustable or non-adjustable control arm. This, again, will come down to a couple of different ways of using your Mustang. Generally speaking, if you want an upgrade on a bolt-on Mustang that will mostly be a street-driven Mustang, then non-adjustable control arms will usually suffice. If you want to use sticky tires at a drag strip to prevent wheel hop or dial in a car for handling, adjustable control arms will be the way to go. There is an exception to this rule: if you are lowering a Mustang extremely low (over 1-1/2" on average), adjustable control arms will help you set your pinion angle back within spec. Any time you are lowering your Mustang, it is always best to check your pinion angle to make you that it does not need adjustable control arms to readjust it back into factory specifications.
Most adjustable control arms for the independent rear in the 1999-2004 Mustang Cobra and S550 Mustang will be designed to correct toe or camber as the rear differential is mounted on a fixed location on a subframe. This means that the pinion axle will not be adjustable. When lowering the independent rear suspension, the wheel camber and toe may need to be corrected, and adjustable control arms are made for this purpose. If you want to beef up the stock components and do not need to correct the toe or camber, then the non-adjustable version will be a great choice!
Height, adjustable control arms found on 1979-2004 solid axle Mustangs are commonly referred to as weight jacker control arms with an adjustable spring perch on the control arm that will allow an adjustment in the height of the rear of the Mustang. These control arms are beneficial in drag racing, road racing setups, or purely cosmetic. If you need to fine-tune the height of the rear of your Mustang, height-adjustable control arms are the best option!
Using the above information, you can help decide which control arm is the best control arm for your Mustang. Aftermarket control arms are always a great way to increase traction and handling characteristics on both manual and automatic transmission Mustangs. Adding additional heavy-duty front suspension parts can further increase the handling characteristics of your Mustang coupe, hatchback, fastback, and convertible.
We hope this has helped you evaluate which rear control arms are best for your Mustang. If you want to purchase and install control arms on your Mustang, Late Model Restoration has plenty of installation tech guides to assist you with this. If you still have any further questions, do not forget to contact us here: CONTACT US PAGE.
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