I always thought I would end up calling a tow truck or a friend if I got a flat tire on my motorcycle. I finally had a chance to test that theory. After working late, I walked out into the parking lot and saw my rear tire was totally flat. I have had excellent luck in the past with the rope and tar tire plug kits on two SUVs. I used them three times as a permanent repair in the main tread area. The only time it didn't work well was in the sidewall near the tread. That was a temporary repair; it began to leak significantly after a few hundred miles or so. I decided to walk to a nearby auto parts store to try my luck with a tire plug kit and a foot pump. I removed the screw, reamed the hole, inserted a rubber-cemented tire plug, rotated the tire, and waited 30 minutes for the cement to set up. I pumped the tire up to pressure and cut off all but about 1/4" of the plug sticking out of the tire. I made it home with no problems.
Sine the tire was on its last legs anyway, I decided to run the plug for a while. As you can see, the puncture was in about the worst possible place. It was right on the edge of the main upright contact patch. I checked the pressure before every ride and topped the tire up about 5psi every morning. I got curious about whether the rubber cement helped since it was intended for the inside patches and not the plugs. I put another hole the same distance from the center line, but on the opposite side of the tire. I reamed it and plugged it, but without rubber cement. Here are the initial plug after about 100 miles and the second plug after only a few miles.
With both plugs, I had to top up the tire about 10psi every morning. That works out to around 5psi per plug per day. I decided to put together a little tire repair kit to keep on my motorcycle, but there is not a lot of room on sport bikes for this kind of stuff. I ended up storing four plugs inside a mountain bike pump.
I ran the repaired tire as long as I could to test the limits. The plugs held up great and I even relied on the tire for a few hundred mile ride through the hill country. I rode hard a few times, but took it easy most of the time. I put 700 miles on the initial plug and 600 miles on the second plug. The plug seems at least as tough as the surrounding rubber. I stopped my test when I noticed a dramatic increase in the leak rate. I could see steel wire glistening through cracks in the rubber in the last photo. It's finally time for a new tire, but I guess I got my money's worth out of this one and I learned a lot about the longevity of simple tire plug repairs.
