Alligator Brand Double Valve Caps -- Safety Concern

[Gil_J]

Many have heard of the benefits of the Alligator double valve caps. The company primarily markets these as a time saver, claiming commercial operators can reduce tire pressure checks from 30 minutes to 6-7 minutes. I can’t imagine a coach owner that doesn’t have the extra 25 minutes to check tire pressure with conventional valve stem caps. But why not use these double valve caps? Plain and simple, they leak!

http://www.benzworld.org/forums/attachment.php?attachmentid=243442&stc=1&d=1244777271

I recently installed new Alligator brand double valve caps and awoke to two tires that where almost flat. If I was using good quality brass valve caps with high temperature grommets I doubt I would have awoke to deflated tires. I wondered if I just happened to have gotten bad caps. I doubt it as simple as they are. Then I discovered others have also experience deflated tires using these double valve caps.

In my case, a previous owner installed Equal in the tires but the valve cores were not replaced with the Equal valve cores with screens. Given valve core failures are somewhat rare, might explain why I haven’t heard of a large number of complaints with the double valve caps. If they weren’t marketed as having a sealing capability that would be different, but the Alligator brand is.

Not all suppliers or manufactures make claim that these double valve caps will seal against valve core leaks. As an example, I don’t know which manufacturer’s double valve cap product Alcoa sells, but they limit their claims to the following.
“Double seal valve cap seals at the top of the cap which prevents dirt and water from penetrating the cap, eliminating the chances of clogged air passages due to ice and debris.”

Clearly, Alcoa steered clear of the caps ability to seal against valve seal leaks.

I know I’ll never use the double valve caps again. Sure, I may be 30 minutes behind you leaving an event, but tire safety is too important to me not to take advantage of brass valve caps with high heat sealing grommets.13927

Before anyone brings up TPMS products, I won’t use them either until a reliable in the wheel system is available. I know those that have benefitted from their TPMS and I agree they are a valuable technology. The bad news is there are stories of slow leaks and misinformation that covers all brands of valve stem mounted TPMS systems currently available.

FWIW, my valve stems didn’t have Equal cores because the cores would not fit in the valve stems. I have sense replaced the stems and installed the correct cores. BTW, don’t think that mobile tire service trucks are equipped with an assortment of every stem. The one they won’t have is the one you really need.

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[dale farley]

Thanks for the info Gil. I did have these on all wheels, but now I think I have only a couple. I'll change those two to a standard cap.

[Denny]

I too have had failures with the valve caps you are talking about. I'm not sure of the brand but they failed to seal as yours did. Some of my failures occured while the bus was sitting in my bus barn and I have an air compressor to refill the tires.

I have Equal in all my tires and the Equal valve cores also. They are not perfect but better then the regular cores. Also, with Equal it is imparative to give an extra blast of air to clear any product that may be in the valve core. Since I don't have an accurate air gauge on my tire inflator, I use a truck tire gauge to check pressure then switch back to the tire inflator and give a blast of air to clear the valve stem.

So, with Equal valve cores and the extra blast of air I have still had valve core leaks. I went to the double seal, flo through valve caps for added protection and they have failed on a few occasions.

I have the SmartTire tire pressure monitor system and it has saved me several times. I usually check tires a day or two before I leave and if I have a problem upon leaving I see it immediately . There are 3 truck stops within a mile of my home so I can stop and correct the problem pronto. Since a 20 percent loss of air pressure can ruin a tire if driven on, it is so important that we use every tool available to us to help prevent tire problems.

[cthalfman]

I have had similar experiences with these caps. I as well had all of my valve stems replaced with the extended versions with filters for equal. My experience is that they will often leak after a simple pressure check with a gauge. I check my tire pressure every day the coach moves and use the following process that has had leak free results.

Prior to checking my tires I clear the valve stems of equal with a quick blast with the air chuck. I then check the pressure with the gauge. The last step is I brush the valve stem with soapy gas leak detection solution to be sure they are not leaking.

Prior to using the air blast first to clear the valve stems I detected a leak many times after checking the pressure. I have not had a problem since I started doing this.

I use a portable C02 power tank to give each valve stem a quick clearing blast.

[jbchevy3]

I use a double valve cap that looks like the alligator, but is sold by Allied Tire. I actually had one save a tire, by holding pressure when the original valve core started leaking. I have had no trouble.