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Magnum 500 Center Cap Lock

Magnum 500 Center Cap Lock

By Rick Maginnis


To help secure and prevent theft of Magnum 500 center caps, a simple 60 cent retaining ring may be installed using snap ring pliers.

Figure 1 shows the components involved. In this example, a center cap for the small 2 inch hole Magnum 500 is shown. The relaxed diameter of the internal retaining ring is approximately 2.1 inches as illustrated in figure 2. After the wheel is removed from the car, the retaining ring is compressed with the pliers as shown in figure 3 and placed into the back side of the center cap. When installed (figure 4) the retaining ring expands causing the center cap's metal holding clips to firmly grip the outer edge of the hole. Voila! The center cap will not rattle or come off while driving and is darn near impossible to remove without first taking the wheel off the car - cheap security!

The 1-15/16" steel internal retaining rings used in this example were obtained online from Barnhill Bolt Co., Inc., Albuquerque, New Mexico. Part no. #N1300-193 at a cost of 0.62 each. (shipping was twice the cost of the parts.) Another near optimal ring would be the slightly smaller 1-7/8" part #1300-187. Evidently, there is considerable variation in hole diameter from one wheel to the next. The smaller size was experimented with first and fit well on one spare Magnum 500 wheel but didn't provide as much gripping force on four other wheels, hence the use of the slightly larger 1-15/16 ring. Buy both - mix and match as required. For 2-1/8" hole diameter Magnum's a larger retaining ring will be necessary.

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Figure 1. Retaining ring and pliers shown with center cap.

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Figure 2. Ring diameter (relaxed)

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Figure 3. Ring installation

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Figure 4. Ring installed

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This page last updated: January 02, 2015