We wanted to address a topic that we feel is often overlooked when most people are installing new suspension on their vehicle, especially coilovers. While it may not seem important at the time, a lot of a suspension’s longevity and comfort hinges on these components so let’s discuss them!
What are “upper strut mounts”?
The linear spring is probably what first comes to mind when you think of coilovers. Often, most coilover companies show images on their website and in their advertisements with linear springs for two obvious reasons: it is the most commonly type of spring used and they picture well. The linear spring is most times uniform in shape and has equal distance between each spring coil:
For those unfamiliar with the terminology, upper strut mounts will be the components installed on the top of your shock/spring combination that allows the suspension to be bolted to the top side of the wheel well. Upper strut mounts often will consist of several parts but essentially will hold the top of the strut assembly to the vehicle.
For most late model vehicles, the front upper strut mounts consist of three main parts: mounting plate, upper strut bushing, and upper strut bearing. In many cases the mounting plate, part that will have hardware to physically mount to the vehicle, can be one piece with the upper strut bushing. The bearing will not be necessary for the rear and the rear setup will often only include mounting plate and upper strut bushing.
Why do I need new upper strut mounts?
Each of the strut mount components above has a specific job and is critical to how the overall suspension system functions. Most Raceland coilovers will require you to use factory-spec upper strut mounts for installation. If the vehicle is more than a few years old, we typically recommend replacing the factory upper strut mounts with new factory-spec units and here’s why…
Mounting plate and bushing
It’s not hard to understand why an automotive bushing would need to be replaced. Simply put, it wears out! The bushing is the buffer between shock/spring and body of the vehicle. Not only is the shock and spring compress when driving down the road, that bushing is also constantly getting squished between spring and body. Over the weeks, months, and years this bushing is constantly getting softer and softer as it deteriorates until it will fail or tear completely if not replaced. When installing new suspension with old bushings, you run the risk of not getting the full performance and comfort potential of that suspension when not replacing this bushing. This can often make the suspension spongey in feel and performance and not how the original manufacturer designed the vehicle to handle and perform.
Upper strut bearing
The bearing is similar to the bushing in wear but serves another function as well. When you turn the steering wheel of your vehicle the strut housing will rotate with the wheels. Since the top mounting plate is bolted stationary to the vehicle, it is the bearing’s job to allow the strut housing to rotate without issue. Since the bearing is being squished between shock/spring and body of the vehicle as the bushing is, it too will deteriorate and break over time when not replaced. When this piece begins to fail you’ll notice a heavier steering feel and will essentially be forcing the strut assembly to twist with the turning of the wheels rather than moving freely. This puts more stress on the shock and spring and can cause spring noises when turning the steering wheel and often premature failure of the shock.
Quick note on pillow ball mounts
A few of our coilover options will include the upper strut mounts so that will not be necessary to replace for proper installation. These often include pillow ball mounts that replace the rubber strut bushing with the metal spherical bearing. Because you are removing the rubber insulator for the mix, these often can lead to a slightly stiffer ride and more road noise transmitted into the vehicle. The tradeoff would be that these often can perform better and have more adjustment than factory mounts. Most coilover pages on our website will be a photograph of the actual coilover kit, so if you do not see mounts in this picture it is safe to assume they won’t be included with your kit.
So, I should replace them?
We’d definitely recommend doing so! For the reasons above, this will only help the vehicle perform and last at its best. They’re relatively inexpensive parts to add to your coilover install and can make a world of difference. We offer several upper strut mount fitments but if it is something we currently do not offer you can often find reliable parts at your local auto parts store. See the link below for the fitments we offer. If we do not offer one for your vehicle feel free to reach out to us and let us know so it can be something we offer in the future.
2 thoughts on “Do you really need new upper strut mounts when installing coilovers?”
I have just replaced the upper strut mounts on my Rover 75.The mounts contain rubber bushes and a rubber coated bearing allowing the hub carrier and strut to rotate for steering.With the refurbished strut firmly in a bench vice I found it quite stiff to rotate the upper strut mount by hand.Is this typical occurrence or have I assembled the strut incorrectly.
That is normal. With the weight of the vehicle, that bearing set should work without any issues.