M20E Main tire tube size and stem

[takair]

70deg on order.  It looks like the stem may be slightly shorter than the 90 as well.  Will post pics.  Fingers crossed.

[47U]

2 minutes ago, RLCarter said:

If I didn’t know better I would think you had been in my hangar a took a picture of my tube...... going with the 70°, will be replacing both main gear tubes

Yeah, I wasn’t paying attention and bought the wrong tubes.  I thought they assembled in the wheel just fine, but bending the stem over to put the air chuck on it was apparently too much for it.  These were less forgiving than my previous tubes with the same straight stem, which never gave me a problem in the seven years it took to wear out the tires.  

Don’t tell my comptroller, ok?  

[Andy95W]

@Skates97 put 90° tubes on his M20C.  He can probably provide some good insight, and hopefully a picture.

[Immelman]

Looking forward to your pirep takair...

This annual (a month ago): Re-installing MLG wheel dust cap after after wheel R&R: Whooooooosh. That was from a nice Michelin leak guard tube. Stem cracked at the base. At least it had a decent service life.

I wish had had the forethought you had to investigate alternatives as you are now.

Edited December 14, 2020 by Immelman

[Jeph357]

4 hours ago, takair said:

Thanks @Bob E!!  This is the confirmation I was looking for.  Surprisingly hard to find details on this subject.  They also have a 70degree version.  Any pictures of your 90 degree install?  Would 70 degree provide benefit?  

I had a similar experience was lucky I didn't ruin my rim or anything. Used every bit of the runway width wise. I had to use straight valve to get back in the air but ordered 70° and have been happy ever since. Pics are of how close I came to going off  edge of runway and my valve stem I found doing a FOD check riding back with the airport ops guy. I did check my tire pressure before the 3 hour flight. If I remember correctly the tires/tube were installed a little over 2 years prior to me buying the plane. I make sure to use alot of talc powder. Wont hurt anything.

[RLCarter]

15 hours ago, Bob E said:

The stem is centered on the nose wheel but not on the mains.  (See photos)   Although I don't have any straight-stem spares, as I recall the straight-stem tubes for the mains are also off-center to the same extent.

You are correct, straight rubber stems are off center or at least mine are, just checked them an hour ago

[Skates97]

14 hours ago, Andy95W said:

@Skates97 put 90° tubes on his M20C.  He can probably provide some good insight, and hopefully a picture.

These are the ones that were put on my plane a couple years ago. They have the 90° angle stem. The Goodyears are the only ones that Aircraft Spruce had at the time that were 90°. The description is weird because it has A and B in it, but the AS number is the 06-05305.

https://www.aircraftspruce.com/catalog/lgpages/gy_tire66.php

I don't have any good pictures on my computer but was able to find this one and crop it down. The stem does not stick out past the wheel.

[Don Heene]

Got my tube at Aircraft Spruce a year ago just to have on hand and when I needed it,  just recently discovered it had a leak in it before putting it in the new nose tire                    ( Manufacture defect)  Note to self check the tube as soon as you get them.  Aircraft Spruce will not take them back if a year old.  $99.00 lesson learned the hard way.    

[takair]

19 minutes ago, Don Heene said:

Got my tube at Aircraft Spruce a year ago just to have on hand and when I needed it,  just recently discovered it had a leak in it before putting it in the new nose tire                    ( Manufacture defect)  Note to self check the tube as soon as you get them.  Aircraft Spruce will not take them back if a year old.  $99.00 lesson learned the hard way.    

These pinhole leaks are way to frequent.  Who made that tube?  Is the the 90 degree stem or 70?

 

[Don Heene]

1 minute ago, takair said:

22 minutes ago, Don Heene said:

Got my tube at Aircraft Spruce a year ago just to have on hand and when I needed it,  just recently discovered it had a leak in it before putting it in the new nose tire                    ( Manufacture defect)  Note to self check the tube as soon as you get them.  Aircraft Spruce will not take them back if a year old.  $99.00 lesson learned the hard way.    

These pinhole leaks are way to frequent.  Who made that tube?  Is the the 90 degree stem or 70?

 

Goodyear Tube  90 degree for the nose wheel  

[RLCarter]

Question for those that have installed the metal valve stem tubes, there are 2 nuts pictured below, if this is the same of the thousands of non-aviation tubes I’ve installed the one circled in blue goes inside the rim and one circled in red goes on the outside of the rim tightening it place. The thickness of the rim seems greater than the threaded part circled in blue. So here’s my questions; do you leave outside nut off? Do you use any type of rubber grommet around the stem due to the difference in the hole in the rim and O.D. of the metal stem?

[cliffy]

History lesson on tubes

There were SHORT stem and and LONG stem tubes way back when. 

Finding a SHORT stem tube today is like finding gold in the parking lot. They don't make them anymore TIKO

The cure that some have tried is to use an 8.00X6 90 degree valve stem tube. Some say it fits perfect with no fold overs inside the tire to wear through. Some reports of it lasting the life of the tire.

[cliffy]

On 12/14/2020 at 6:44 PM, Don Heene said:

Got my tube at Aircraft Spruce a year ago just to have on hand and when I needed it,  just recently discovered it had a leak in it before putting it in the new nose tire                    ( Manufacture defect)  Note to self check the tube as soon as you get them.  Aircraft Spruce will not take them back if a year old.  $99.00 lesson learned the hard way.    

Seems I recall tire tube patch kits from long ago  :-) :-)  They never seemed to fail?

[Immelman]

57 minutes ago, cliffy said:

Seems I recall tire tube patch kits from long ago  :-) :-)  They never seemed to fail?

I carry patches for my bike inner tubes. They work! Even at higher pressures, 70psi, 120psi road bike...

Then I bought a newer mountain bike, things have moved on, now its tubeless with some goop inside that seals punctures.

Too bad aviation doesn't move on easily.

[takair]

So, a few findings.  The flat turned out to be caused by a small split in the tube, not the stem!  There is no indication why it split.  No pinch, no rough spots, still had dry talc, held air very well until the flight that it didn’t.  I don’t understand why this would have happened.

The good news is, the 70* stem seems to be the way to go.  Perfect fit and leaves the stem easily accessible.  Images below of the straight stem, the split, the new tube and after.

[RLCarter]

My tubes are due in next week, mine was definitely leaking at the stem...... yours almost looks like it was pinched except there generally a matching one very close.

[RLCarter]

Installing the 70° stems was the best 2.5hrs spent.... well this week anyway  

[outermarker]

For those who want to know more about all things Goodyear Tire.

Aviation-Databook-2022.pdf (goodyearaviation.com)

aviation-tire-care-2020.pdf (goodyearaviation.com)

Tire Care & Maintenance Manual | Goodyear Aviation Tires

 

[A64Pilot]

One day we will grow up and go tubeless and have sealed bearings too, tubeless is wonderful trust me. From what I’ve seen the majority of flats are from tube failures, and not all flats end well.

I keep hoping for an STC, but I’m not holding my breath. Maybe with CNC 6061 wheels instead of magnesium, because that’s a whole lot cheaper in smaller quantity to manufacture.

I think it could happen because I think our wheels are used on the majority of GA airplanes, not just a Mooney thing.