Valve stem clearance

How to keep the Cessna 170 flying and airworthy.

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flyboy122
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Joined: Mon Apr 21, 2014 2:30 am

Valve stem clearance

Post by flyboy122 »

I'm getting ready to order some new tires/tubes for my 170, and noticed that Desser offers a tube with a 90 degree valve stem. At first glance this seems pretty attractive as it may allow me to air the tires with the wheel pants on. Does anybody have any pireps on these? Do they fit under wheel pants?

Thanks,
DEM
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Bruce Fenstermacher
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Re: Valve stem clearance

Post by Bruce Fenstermacher »

I think Richard Pulley just wrote about this subject a month or two ago though he was coming about it another way. That of a valve stem ripped off the tube. Thought he had the wrong tube(s). Found later he didn't but there was two different valve stem designs. One that works and the other that will get ripped off. At least this is what I think I remember. Look up Richard and inner tube or valve stem and see what you find.
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Bruce Fenstermacher, Past President, TIC170A
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Bruce Fenstermacher
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Re: Valve stem clearance

Post by Bruce Fenstermacher »

Found the post I was thinking of. http://www.cessna170.org/forums/viewtop ... inner+tube

Quick read it again and didn't find what I thought was there. You might want to look it over to be sure I didn't miss anything.
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hilltop170
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Re: Valve stem clearance

Post by hilltop170 »

I did not have 90 degree valve stems. I think my tire slipped on the wheel and sheared the valve stem but that is only a guess as the other tire had slipped and the valve stem was bent over about 45 degrees.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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GAHorn
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Re: Valve stem clearance

Post by GAHorn »

I DID order the 90-degree valve stems from Desser for the same reason as yourself, DEM... and I will not do that again. The 90-degree did not facilitate airing-up the tube with the wheel fairings on as well as the straight-'rubber stems did. Typically, I roll the tires until the red-dot-balance mark is at the 6-o'clock position below the fairing...then loosen the axle-mount-AN-bolt to pull the fairing sufficiently outboard to be able to reach-in and flex the rubber stem down sufficiently to air up the tire.
It leaves near-cuts on the back of my hand to do it this way....but it's worked for 20+ years. When it came time to replace tires/tubes a year or so ago I ordered the 90-degree stems. I found that they do not actually exit at an accurate 90-degree when aired-up to 28 psi..... in fact, the end of the stem places the threaded-portion hard against the wheel-rim. This required me to attempt to flex the brass tube-end away from the wheel in order to fit the "Milton" connector (air-fitting) onto the valve stem in order to add air.
One of the brass tube/valve-stem immediately fractured and broke off at the bend. (I suspect the brass is not annealed after bending. It was brittle like glass.)
$65 wasted.

I've returned to using the straight rubber stems.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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