Inner tube stems

[Bob E]

IMHO very few mechanics, even Mooney mechanics, take notice of this issue.  In years past, before I discovered bent stems and just let the shops maintain the aircraft (Clyde Wittenbrook for those who recognize the name), they did excellent work but nonetheless it was impossible to install the straight-stem tubes specified without bending - and straining - the stems.  (Photo)

So after switching to bent stems, before I started mounting tires myself, I didn't realize that the bent stem, when installed properly, does not touch the rim. The shop guys (usually assistants) who do the installation don't realize it either.  If they were willing to install straight stems that look like the photo and not raise questions, then they definitely won't notice if a bent stem touches the rim.

 

[Jim Peace]

5 hours ago, Bob E said:

IMHO very few mechanics, even Mooney mechanics, take notice of this issue. 

Its frustrating to have a little bit of knowledge and ethics in this world...

[kortopates]

IMHO very few mechanics, even Mooney mechanics, take notice of this issue.  In years past, before I discovered bent stems and just let the shops maintain the aircraft (Clyde Wittenbrook for those who recognize the name), they did excellent work but nonetheless it was impossible to install the straight-stem tubes specified without bending - and straining - the stems.  (Photo)
So after switching to bent stems, before I started mounting tires myself, I didn't realize that the bent stem, when installed properly, does not touch the rim. The shop guys (usually assistants) who do the installation don't realize it either.  If they were willing to install straight stems that look like the photo and not raise questions, then they definitely won't notice if a bent stem touches the rim.
 

What kind of tube does your IPC call for- angled stem? I’d be surprised if Mooney spec’s a tube with stem that rubbed against the wheel.


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[Jim Peace]

1 hour ago, kortopates said:

I’d be surprised if Mooney spec’s a tube with stem that rubbed against the wheel.

[Bob E]

From the M20C Type Certificate (Aircraft Specifiation No. 2A3, Revision 52, Dec. 9, 2010).  And there you have it.

 

[47U]

7 hours ago, Bob E said:

And there you have it.

Thanks for posting the Type Certificate excerpt.  A caution to the early short-body owners, your IPC may show a 4-ply tire on the nose.  When the F/G models came out in ‘68, the IPC showed a 6-ply tire on the nose and a 4-ply tire on the C/D/E.  The 6-ply tire is listed in the last version of the vintage models IPC, Manual 205.  The 4-ply tire was removed altogether.  

[outermarker]

Earlier this year, I replaced the main gear tires with Goodyear Flight Custom III. This tire provided 10 years and 100's of hours of worry-free service. The inner tubes were from a vendor I couldn't find anymore, so I purchased Aero Classics Butyl Leakguard tubes because they were the only inner tubes with a 70 degree bent stem. The valve stem doesn't touch anything, including the dust cover. And yes, I cried when I wrote the check. 

[skipswift]

On 9/10/2025 at 10:48 PM, Bob E said:

IMHO very few mechanics, even Mooney mechanics, take notice of this issue.  In years past, before I discovered bent stems and just let the shops maintain the aircraft (Clyde Wittenbrook for those who recognize the name), they did excellent work but nonetheless it was impossible to install the straight-stem tubes specified without bending - and straining - the stems.  (Photo)

So after switching to bent stems, before I started mounting tires myself, I didn't realize that the bent stem, when installed properly, does not touch the rim. The shop guys (usually assistants) who do the installation don't realize it either.  If they were willing to install straight stems that look like the photo and not raise questions, then they definitely won't notice if a bent stem touches the rim.

 

So what did we do wrong that the stem sits tightly against the wheel hub for the nose gear wheel (see my attached photo).  This is an Aero Classic TR-87 tube with 90 degree stem.

Edited Wednesday at 07:52 PM by skipswift

[Bob E]

That photo is of the nose wheel.  All nose wheels on Mooneys of our vintage have bent metal stems (AFAIK).

The correct tube is a TR67A, a 500x5 tube.

The TR87 is the short-stem version.

 

[Hank]

Quick tube question:  I'm about to replace my main tires, and remember reading recently about talc. Checked my baby powder bottle, it's corn starch and has no talc. 

How can I find real talcum powder these days? or should i just use the new no-talc baby powder? 

[cliffy]

You are correct that Johnson and Johnson baby powder is now corn starch

Talc is available in the pharmacy if you look around or buy it from Spruce

[Bob E]

Hank, see my Aug. 27 post.  That cheap bag of tire talc is enough to supply an entire GA airport for about 10 years!

 

[Hank]

13 minutes ago, Bob E said:

Hank, see my Aug. 27 post.  That cheap bag of tire talc is enough to supply an entire GA airport for about 10 years!

 

I remember reading it, but couldn't find it. Is that the Spruce bag, or amazon?

[Andy95W]

https://www.oreillyauto.com/detail/c/xtra-seal/xtra-seal-powder-tire-talc/xts0/14550

[cliffy]

The jungle store also has 2 different tire talc bottles for sale   Both 1pound