Recently, I uploaded a video where I replaced a faulty rear end link on my 2010 Mazdaspeed 3, which itself was a replacement of the factory end links I removed when I installed a stiffer rear sway bar from James Barone Racing. The end links are an important suspension component, connecting the sway bar to the chassis, helping to eliminate body roll and improve tire grip. Whenever there are changes to the suspension (in this case, the addition of a stiffer than stock sway bar) changing the end links is always a good idea. There is nothing more annoying that hearing a failed sway bar end link knocking while driving. Sure you can turn the stereo up, but that really doesn’t fix the issue!
That knocking sound…
If you have been following the channel (and you should be following the channel), you will know that I have been chasing a knocking sound coming from the rear of my car for some time now. Replacing the rear end link was a step in the right direction to fixing the issue and while I was doing my research and troubleshooting in the that particular problem, I stumbled on to another potentially annoying issue that I have ignored. Well not really ignored, I just did not realize that it was ACTUALLY a problem.
Way back when I installed the RaceWorks coilovers on my car, there has been a complaint on my part about the steering feedback, the steering did not “feel” right to me. When I would turn left, the car response was almost immediate, a small amount of wheel movement would turn the car. But turning right, it seemed the car took more wheel motion, much more than the left. At the time I passed it off as a bad alignment, since it was after the suspension installation, but the issue persisted after the car was aligned. Time and other issues on my mind pushed my reservation to the back of my mind and I really did not think about it until I was researching the rear end noise. That was when I stumbled upon the answer to a problem I had long forgot about asking. The reason why the steering felt “weird”?
The front sway bar had too much preload.
Sway Bar Preload and You
So what exactly is preload and why does it matter? Good question. I will try to explain this as easily as possible without this article turning into a thesis on suspension theory!
A sway bar’s job is to combat the rolling forces experienced by a car while it is turning. By connecting the left side suspension to the right side suspension, the sway bar counteracts body roll and forces the car to maintain an almost even leveled attitude while cornering, which improves grip. When the car body rolls to the side under cornering, the weight that is being shifted is known as “loading the bar”.
Sway bar preload for this discussion is a side to side movement. For a car that is going to turn left and right, you want the sway bar to have zero (0) preload on it at rest. If the bar is preloaded, it means that it’s already twisted when the car is at rest, and it’s trying to roll the car to one side because of it. The side that is preloaded will cause the steering to oversteer in that direction and understeer in the other direction. One of the symptoms I was plagued with was a car that was very dart-like while turning left, but sometimes a little sluggish by regard, when turning right. When I lowered the car after putting on the coilovers, sway bar preload was not even on my radar, I had forgotten that when you make a change to the car, there are other changes related to it that need changing too!
Changing the ride height changed the suspension geometry. When at stock height, the stock front end links were fine, but now that the car was lowered, that was no longer the case. After working on the rear of the car, I figured this was as good a time as any to replace the stock front end links, and see if I can fix my preload problem as well.
Massive Speed System Adjustable Front End Links
The set of end links I decided to use are from Massive Speed System . From their site ” Perfect for your performance lowered vehicle! 6061 Aluminum tube construction for light weight and strength – tapered for max range of motion. Cost-no-object fully lined US Made Aurora spherical rod ends provide superior accuracy, no noise and lubrication free operation. Rod ends are properly swedge-studded for strength, ease of install and will not come loose. INCLUDES essential rod end boot to keep out dust/dirt/road salt – a must for longevity. Supplied with high grade yellow zinc plated purple insert Nylock nuts and washers for corrosion resistance.“
Shipping was quick (they are located in Illinois) and everything came nicely wrapped. All hardware for installation is included and the ball joints are pre-greased. Installation should be a simple remove/replace affair. One of the features that I really liked about these end links is that there is a nut that you can get a wrench on to help secure the ball joint from spinning when tightening/loosening the lock nut. Anyone who has tried removing the stock ball joints will appreciate this.
Stock vs Adjustable
I hope that you have a somewhat understanding about sway bar preload and what it does. So how does one adjust a sway bar for zero preload?
With the stock end links, you can not adjust for preload. If your car is at stock height, this will not be an issue for you. When the end link fails ( usually around 40,000 mi) just remove the old one and replace it, you will be good to go.
If you add a coilover suspension and are at lower than stock ride height, depending on the suspension, OEM front end links might not work for you. Not all suspension manufacturers use the stock mounting location for the upper end link, so do your homework before hand. You may require a shorter/longer end link.
To adjust for preload, the car needs be on the wheels on flat ground. Adjust one end link to stock length and install it on the car. On the other side of the car, install the second end link, but DO NOT move the bar to attach the lower end link. Instead, lengthen/shorten the adjustable end link until you can slide the the link into the bar easily.
Does having preload properly adjusted help driveability? That is a big 10-4! The issues I have been having with the way the car behaves are now gone! The car is responsive turning left and right and the steering feels “right”. If your own car is modified and you think that a preload issue might be at hand, I highly recommend purchasing a set of adjustable sway bar end links.
Now to track down that pesky rear end noise!