If you have gashed or scraped a small patch of sidewall rubber on your car, truck, or bike tire down to the threads, but not cut the threads, most people will advise you to get a new tire.
There is at least one repair alternative that will get you a few miles down the road until you can get a professional repair or replacement. Note that this method only works if you have not cut the sidewall threads or cords. If you have cut the threads, replace the tire at once.
NOTE: First get
a professional tire inspection. Then, get a permanent tire repair or replacement when possible. This article in no way aims to promote unsafe tire repair.
If you have doubts, get an inspection, then use some common sense and do the right thing.
TOOLS YOU NEED
You will need some carb cleaner or other solvent, a good automotive patch kit (Monkey Grip brand worked for me), and an elastomeric type spray-on rubber product. Spray-on electric tape and Black Plasti Dip Multi-Purpose Rubber Coating are a few to consider. Also you might want to use an extra amount of rubber cement or other elastomeric cement for filler. Goop brand glue works too, but it tends to get more brittle in the weather, especially if exposed. It seemed to do OK under the patch.
Finally you will need some common sense. Although you canít get this at the hardware store, it is important. If your tire is gashed real deep (over a few millimeters or so) you cannot fix it without a Bandag machine or something. Do NOT waste time and money on tire sidewall repair and create a blowout if the sidewall is cut up badly.
First, carefully inspect the sidewall. Then inspect it again, then maybe a third time. Better yet, take it to a reputable tire shop and have them inspect the tire.
I did this and learned that the sidewall threads, while not cut, were exposed.
You need to be sure the threads of the tire are intact. The threads are what do the work of supporting your vehicle. Once you are convinced that all you did was
scrape off some of the rubber, or create a shallow gash, move on to step 2.
Second, clean out the gashed area with carb cleaner. Let the cleaner dry and the surface will be ready to take some filler and cement.
Third, apply filler as needed to level the dip in the tire, if there is one.
Next, roughen up the damaged area outside the filler. Do this just like you would if fixing a flat in a bicycle tube.
Apply the rubber cement, again just like placing a patch on a bicycle tube. Apply the patch and press until it sticks on really well; then keep pressure along the edges until it all sticks tight. Note that the patch will probably not vulcanize to the tire as well as to a bike tube, but with a little time and care it will stick on there pretty darn well. It is now time to finish the tire sidewall repair. Mask off the white letters on your tire and paint on the vehicle, as needed. Apply the black elastomeric spray to the repaired area. Put on as many coats as needed to fill in gaps, small scratches and the patch itself.
I did not do this since the idea for the spray-on rubber came well after the patch. But you could perhaps just clean the damaged area with solvent, mask off the area, and spray on the rubber as needed.
INSPECT AND USE
Once more, if you are certain that the repair is safe to drive on, give it a test whirl. My repair held well through rain, snow, heat, and back roads. Note that vehicle/tire speeds were kept within the speed limit.
The thing to remember here is that this is only a temporary repair. You will need to keep an eye on the repair and touch up as needed until the tire is replaced.
This article in no way encourages people to make a bad situation worse. Go to a tire shop ASAP. Do not attempt your own tire sidewall repair unless confident of your abilities. Use common sense and be safe. If you make your tire worse, you have been warned.