Michelin AirStop isn't

Dgamble · #1 01-23-2007, 05:58 AM

Stopping the air, that is. I've developed a slow leak in one of my mains. What's the typical corrective action for something like this? Remove the rube and patch it, or just replace the tube?

Ironflight · #2 01-23-2007, 06:27 AM

First thing I'd do is remove the valve core and reseat it, then refill the tire and see if that has fixed the slow leak (unless you already know that the leak is someplace else from bubble testing).

Just a place to start....

Paul

N62XS · #3 01-23-2007, 07:35 AM

Bought new Mickey Airstops and new tubes. After about a month, each was down about three pounds. I did what Paul suggested. Next month, same thing, down about 2.7 pounds. Through a series of calls, I finally got in touch with a factory aviation rep and the result of the conversation was that all tires loose air. To minimize the loss, he said to use nitrogen to inflate the tires because "nitrogen molecules are larger and cannot escape as easily through the rubber tube". When I pointed out that nitrogen was an atom, not a molecule, the conversation ended.

I will use these up and switch back to the cheap stuff for the following reasons. Air loss makes one inspect the wheels/tires/wheel pants/brakes more often. More frequent changes of tires give you the opportunity to service the wheel bearings more often and warrants more detailed inspections of the above areas. If you do not fly but 30-50 hours a year, it saves money on tires and tubes. Lastly, I plan to use the tires on this link:

http://gikonfinsh.blogspot.com/2006_...h_archive.html

This is what I plan to do and I hope it works for me. I'm sure there are other solutions out there and would love to hear differing opinions.

AlexPeterson · #4 01-23-2007, 07:39 AM

I've used Michelin Airstops for several years now. I maybe put air in them every 6 to 8 months. The go from about 45 psi to 35 or 40 in that time period.

ptrotter · #5 01-23-2007, 07:52 AM

With respect to nitrogen being an atom or a molecule, it is both. The common form of nitrogen in the atmosphere being molecular nitrogen N2. Frankly, I don't think it would make much difference air or nitrogen since normal air is 78% N2 anyway, the remainder being mostly O2 which actually has a slightly higher molecular weight than N2. The primary advantage of nitrogen is that it is inert and does not react with anything and will not cause any corrosion or deteriation of any mateial it contacts.

CraigH@KRPH · #6 01-23-2007, 08:47 AM

Quote:

Originally Posted by AlexPeterson

I've used Michelin Airstops for several years now. I maybe put air in them every 6 to 8 months. The go from about 45 psi to 35 or 40 in that time period.

I put on a set of the generic Leak Stop tubes sold by Desser last September. Haven't put any air in the tires since.

airguy · #7 01-23-2007, 09:03 AM

Quote:

Originally Posted by ptrotter

With respect to nitrogen being an atom or a molecule, it is both. The common form of nitrogen in the atmosphere being molecular nitrogen N2. Frankly, I don't think it would make much difference air or nitrogen since normal air is 78% N2 anyway, the remainder being mostly O2 which actually has a slightly higher molecular weight than N2. The primary advantage of nitrogen is that it is inert and does not react with anything and will not cause any corrosion or deteriation of any mateial it contacts.

Nitrogen will be interfered with more effectively than the oxygen by the carbon-sulfur bonds in the rubber, significantly slowing it's elution through the tube and tire. Pure nitrogen will still lose pressure in a tire, but slower than straight compressed air. I was told recently by an A&P servicing a Mitsubishi Diamond (now BeechJet 400A) tire that the main reason nitrogen is used is to make sure it's completely dry to limit microbial action, and so there is no oxygen in the tube to slowly oxidize the inner surface, which causes cracking.

Mike S · #8 01-23-2007, 09:18 AM

Quote:

Originally Posted by Hard Knox

I will use these up and switch back to the cheap stuff for the following reasons. Air loss makes one inspect the wheels/tires/wheel pants/brakes more often.

Interesting thought process here-----------use lesser quality parts to make you do the checks you should already be doing anyway. Preflight.

Lets see, ---if I use hardware from the local Ace, think of all the $$ I can save, and it will make me more viligant about checking the prop, wings, tail etc to be sure they dont fall off---------

Nope, I dont want to start down that slippery slope.

Mike

Low Pass · #9 01-23-2007, 09:20 AM

My Michelin airstops work as intended. 3, 4, 5 months between air addition.

Since "air" is about 78% N2, I would go with the dry characteristics of bottled N2 being the driver for its use.

2 cents

Dgamble · #10 01-23-2007, 11:05 AM

Quote:

Originally Posted by CraigH@KRPH

I put on a set of the generic Leak Stop tubes sold by Desser last September. Haven't put any air in the tires since.

Yep, they're pretty good. Mine took very little air until I recently went to the hangar and found the right side to be nearly flat. I don't think it's a quality or design issue with the tube - it's far more likely that I picked up a puncture somewhere. I've had the Desser retread tires and tubes for a couple of years now with no complaints - if I end up needing a new tube, it'll be from Desser.