My car has a Tire Pressure Monitoring System where there is a small electronic device attached to the valve stem on the inside of edach rim that reads the tire pressure for each tires and send the info to the central computer in the car. When the tire pressure goes lower than the prescribed level you end up with a warning light on your dashboard telling you to check your tire pressure. However, it doesn’t tell you which tire is reading a low tire pressure.
So to help me and make things more convenient I bought these Auto Tire Monitor Valve Caps that are screwed on over the existing valves. When the pressure in a tire dropped more than 5 psi below the maximum (I bought the 32 psi caps) the color would change from GREEN to YELLOW. If the pressure dropped more than 10 psi then the color would change to RED.
Now the issue I have has nothing to do with their functionality, they work as described and they are convenient. The problem is the design. They are roughly about 1″ is length. The tire valve without them are tucked in below the wheel rim. When you add these caps the valve is extended beyond the edge of the rim, they stick out. Now, during normal driving this isn’t a problem. However if you end up rubbing your tires against the concrete curb or ride up along the edge of the curb by accident, the odds are very good that you will shear the valve stem off. Before TPMS became standard on cars this wouldn’t be a major cost issue. The old valve stems cost a couple of dollars. You’d still have the inconvenience of having to change the tire (unless you have AAA) and taking the wheel to a repair shop to replace the valve. But the valve only cost a couple of dollars.
Now, with cars coming standard with TPMS the valve and monitoring system are integrated with each other and can cost from about $60 and up! I have had to replace 2 of my valves because of these caps. As convenient as they are, they’re just not worth it. I paid about $7-8 for the set but the replacement valves have cost me over $140.
I don’t purposely drive my car for the tires to scrape the curbs but minor mishaps do happen, especially when your dealing with traffic and other drivers. I guess I’ll just forego these pressure sensor caps and just use my electric tire pump to check all 4 tires when the tire pressure warning light comes on.