Grease is an important protectant for many parts of your car. While it isn’t used in your engine, it is used in several other areas, including the CV joints on your axles, as well as the grease fittings on your suspension (many newer cars have sealed fittings that aren’t serviceable today). It’s also used in rear-wheel drive applications – a truck’s driveshaft may have one or even two grease fittings. However, if you’re noticing grease on the inner edge of your tires, it means that something has potentially gone wrong.
How this system works:
There are a couple of places that grease on the inner edge of your tires might have come from. The most likely is from the CV joint. CV axles, or constant velocity axles, are used in front-wheel drive cars to connect the wheel hubs to the transmission. They have two joints, one close to either end. The joints are made to be flexible, so that your car can travel over bumps and dips easily without losing traction.
The joints are flexible, and include moving parts. To protect them from damage from dust, debris and other threats, they’re covered by rubber “boots” filled with grease. This ensures that they’re constantly lubricated, and that dust and debris cannot enter and damage the joints.
However, over time, your boots wear. The rubber can become brittle from age, and can crack. Boots can also be torn through impact with debris in the road and more. When this happens, the grease can leak out, and dirt and debris can enter the joint.
Common reasons for this to happen:
Blown CV Boot: If you’ve noticed grease on the inner edge of your tires, there’s a chance that one of your CV boots has blown and is leaking grease out. This is a serious situation. Without grease, the joint is not properly lubricated. Even more worrying, dirt and debris can enter the CV joint and cause serious damage, requiring the entire joint to be replaced. If the situation is caught early, it’s possible that only the boot will need to be replaced.
Damaged Grease Fitting: Some vehicles have grease fittings on their suspension system that enable moving parts to move more easily with lubrication. If one of these is damaged, it’s possible that some of the grease may leak onto the edge of your wheel from a nearby grease fitting.
Recent Lubrication of Grease Fittings: Once upon a time, an “oil and lube” service really lived up to its name, with all of a car’s grease fittings being lubricated during normal maintenance. With most newer cars now having sealed systems, this has become less common. However, if your car has serviceable fittings, it’s possible that grease from a recent service somehow ended up on the inner edge of the tire.
Recent CV Boot or Axle Replacement: If you’ve already had a CV boot blow out and the axle has been rebooted, or a new CV axle has been installed, it’s possible that the mechanic did not clean off the inner edge of the tire after the repair.
What to expect:
A top-rated mobile mechanic will come to your home or office to inspect the CV axles, boots, grease fittings and more. The mechanic will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will inspect your CV axles and boots, as well as any grease fittings on your front suspension in order to determine the source of the grease on the inner edge of your tires. The mechanic may also need to test drive the vehicle to test for symptoms of a failed CV joint, which include clicking during turning, or a vibration while driving.
How important is this service?
If the problem is with your CV boots, having the situation corrected is critical. While it’s possible to reboot a CV axle before the boot blows entirely, or immediately afterward, any use of the vehicle with the boot blown can contaminate the CV joint with dust and dirt. This will eat into the joint itself, causing irreparable damage and requiring the entire axle to be replaced. If you’ve noticed grease on the inner edge of your tires, one of our professional mechanics can diagnose and repair the condition.