One of the most common issues we hear about is wheel vibrations after new tires and aftermarket alloy wheels are installed.
More often than not, the vibrations are caused by little washers attached to the brake rotor or brake drum. These locking washers are called stud clips.
These are found mostly on domestic vehicles produced by GM, Ford, Chrysler, Saturn, and even on some imports like Jaguar.
They seem innocent enough but they need to be removed before installing aftermarket wheels.
During vehicle assembly, these little clips are installed to hold the drum or rotor in place against the hub as the vehicle moves down the assembly line in the factory.
They do a great job of keeping the rotor from falling off before the caliper and brake pads are installed but once the car or truck is assembled, they serve no important function. The clamping force of the wheel and lug hardware is what keeps the assembly together after that point.
Here's what they look like on the hub. They are the small, toothed washers placed around the base of the studs. Notice they are only on one or two of the studs:
They are easy to miss and if they are left on there when you install new alloy wheels, they will cause big problems! Any rust or debris on the surface should also be cleaned off with a wire brush. This rotor surface needs a little bit of prep work before a wheel can be installed on it.
Although they are pretty thin (approx 2-3mm), they will keep the wheel mounting pad from sitting flat on the brake rotor or brake drum. Typically the factory only uses one or two on each hub so the flat mounting pad of the wheel will only make contact with one side of the hub once the lug nuts are torqued. It will feel like the wheel is mounted securely but once you start driving on it, the forces on the wheel from rotating, turning and braking will cause the wheel to rock back and forth on those stud clips.
Imagine trying to stand and balance on a flat metal disc that's sitting on two golf balls. You would have a difficult time staying balanced as you shifted your weight back and forth across the disc wouldn't you? Now you're getting the picture right?
Since the stud clips are normally made from stainless steel, they are harder than the alloy wheel. As the wheel rocks back and forth, the stud clips will quickly dig into the back of the alloy wheel's mounting pad.
The clips actually wear round indents or recesses in the back of the wheel and the resulting gap also creates a space between the lug nuts and the lug seats on the wheel face. The lug nuts are no longer torqued tight against the wheel!
You will soon notice a vibration while you drive the vehicle, especially when you turn or when you apply the brakes. The forces on the wheels change dramatically as you turn or brake and the wheel will rock back and forth violently on the now loose lug nuts and studs.
If allowed to continue, the vibration and rocking back and forth can damage the wheel and the studs. Here's a severe example. You can see the indents from the stud clips highlighted in red, as well as the damage to the lug openings of the wheel highlighted in green. The lug holes are actually elongated and chewed up from the violent vibrations against the studs.
The imprints of the stud clips can be seen at the 9 o-clock and 3 o-clock positions. If driven on long enough, this could cause severe damage and even failure of the studs! Once the lug seats are damaged, the wheel is ruined.
It is critical to remove the clips before installing any aftermarket alloy wheel.
It's a simple process to remove them. You just pry them up with a flat bladed screw driver and cut them off with tin snips or twist them off with a pair of pliers.
This important little step can save you a lot of heartache. It will also save your vehicle and wheels from damage. Here is a handy link for wheel and tire installation. Check it out before you install your new aftermarket wheels.