A few weeks ago, I posted that I was considering using a car tire on the back on my Goldwing when the current tire needs to be replaced. I have developed a few questions that I still have, especially cornering and wet weather performance.

In the previous post that I wrote, I mentioned that an author, Daniel Meyer, has been running car tires on his Valkyrie for over 100,000 miles. In his writings about the car tire, he mentioned that he did an impromptu test on the foot path of the car tire during a peg dragging turn. The way that he described it was that the tire had enough flex in the tire that it stayed nearly flat on the ground. However, I found a great video on YouTube that really shows a different story. Someone mounted a video camara on the underside of his bike, then spent a few minutes turning back and forth at a slow speed, you should check it out.

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The other significant question that I have is relating to how well does the tire perform in the rain. A motorcycle tire is designed to heat up quickly to provide maximum traction. If you want proof of this, take your bike for a ride around the block (my test drive was about 4 miles and I got up to about 55 mph for a third of this drive), then touch your tires. This heat makes the tires “sticky” and causes them hold the road much better than the tires on your neighbor’s Toyota. By the way, this is part of the reason that car tires last 30,000 miles or more… they resist the heat build-up. Regardless of the tire technology for the car tires, it is hard to believe that a bike that weighs a third as much as the car the tire was designed for would heat up this quickly on a street tire. In dry weather, the larger flat surface of the car tire is a big advantage for straight-line power transfer and traction, but in bad weather, this could be a problem. There are some cars tires that are designed to eject the water from under the tire quickly, but these tires are still flat on the bottom. Part of how a motorcycle tire deals with water is the consistent curve of the tire, leaving only a small portion of the tire to both contact the road and to handle water build-up under the tire.

I have also read someone talking about how the 7 sq. in. of contact patch really helps during low speed maneuverability instead of the 2 1/2 sq. in. of the motorcycle tire. Initially, I noticed that the Goldwing had an inclination to want to dive it you turned to sharp. However, I have got used to this and I just don’t turn the forks that sharp unless my feet are on the ground, say backing out of a parking spot.

Am I going towards the “Darkside” and placing a car tire on my bike? I think I am leaning about 45% to yes right now, but I still would like to talk to someone that has used a car tire on their bike through at least one tire, and still choose to put another car tire on again. If you know someone who has, point them my direction, and I will gladly buy them lunch to talk about it.