When installing new tires recently on my 29U Plymouth, I took a close look at the location of the rim latch and the apparent counter weight on the fellow. I noticed that when installed, the rim latch is exactly 180 degrees from the apparent counter weight. Also, some of my rims do not have the rim latch but instead have what I call a hinge pin. Previously I had a bad shimmy that would occur at 35-40 mph or if I hit a bump. I noted that previously I had a rim on the front right wheel with the hinge pin type. I decided to put rims of the latch type on both front wheels. When I test drove the car, no more shimmy! Since I have four rims of the latch type and three of the hinge pin type, I used the four latch type on my wheels and one of the pin types for the spare.