You just landed and rushed to get the airplane in the hangar due to a quickly approaching thunderstorm. Your flight plan is closed, all your post-flight inspections are complete, the aircraft is back in the hangar, the hangar door is closed, your belongings have been transferred from your aircraft to your car, and you are off to catch dinner with your family and friends. Life is good … so you think.
A couple days later, you head out to the hangar for an early morning flight. It is a beautiful day with clear skies stretching all the way to your destination. You commence with your preflight ritual, open the hangar door and pull the aircraft out. As you walk back inside the hangar to gather some additional items and close the hangar door, you notice a few black marks on your floor. Your interest is piqued and you walk over for a closer inspection. Even before your gaze falls directly on the subjects, a knot forms in the pit of your stomach and you realize that you now have three brand-new tire marks on your immaculate painted floor simply because you forgot to place plastic pads under your tires.
We’ve all seen them, those damned tire marks on the hangar floor. They come out of nowhere and bite you just as you least expect them. Floor coatings range from $1.00 to $12.00 or more per square foot. Even the smallest tire mark can ruin your investment with a simple blemish.
Tire marks, or “paw prints” as they are sometimes referred to, are caused from chemical components (plasticizers) leaching out from the tire and chemically bonding with the floor. Heat and pressure are the two culprits that act as catalysts in the leaching process.
There exist two primary heat sources that assist in the leaching process. Thermal radiation from the brake assemblies is one source. The second is from the “friction” between the tire and taxiway/runway. These heat sources are unavoidable. To give you an idea of how hot tires can get from the landing and braking process, just view the YouTube video of Space Shuttle Discovery (STS-114) landing at night. The footage was taken with an infrared camera. At the 1:50 mark, you will witness the tires touch down and immediately glow from the intense heat caused by the friction.
Regardless of its sources, heat takes time to dissipate from the wheel and its accessories. Heat causes chemicals (plasticizers) from within the tire to leach out. The amount that leaches out does not affect the tire but it is enough for your floor coating to be chemically impregnated with these compounds. The weight of the aircraft and the pressure it applies on the tires simply assist the impregnation process.
What can be done?
There is very little one can do to effectively remove these tire marks without damaging your floor coating finish any further. If your floor is in pristine condition with a mirror finish, then any abrasive cleaner will leave swirl marks and a hazy finish in that local area. Attempts to paint over the affected area and “feather” the new paint into the existing finish is nearly impossible to accomplish without a definitive line.
The bottom line is that one should treat tire marks the same way one handles thunderstorm flying: Avoidance. Always remember to position the aircraft onto thin plates of heavy gauge plastic or plexiglass. If time permits, let the tires cool down on the ramp before positioning the aircraft in the hangar. This is the only way to prevent the appearance of tire marks.
I would like to thank Jeff Gaither for providing technical assistance regarding this article. Jeff has many decades of experience in industrial floor coating systems and has overseen many installations at military aircraft facilities, MRO/FBOs, private hangars, food plants and distributor warehouses.