Close Call--Over a $9 Inner Tube!

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drdehave
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Close Call--Over a $9 Inner Tube!

Postby drdehave » Wed Aug 28, 2013 5:02 pm

Guys:

I just had another close call last evening, saved BTGOG, for being a dufus, not willing to spend $9 for a new inner tube. Before I relate what went down, let me say by way of background, that my Sting Sport LSA runs regular 4.8 x 8, 6-ply utility trailer tires and tubes. They are pretty cheap, running about $27-$40 each, depending upon make and model (from the OEM list); the associated tube is $9. But they don't last very long on my plane--especially the way I take off and land. If I'm landing a lot, I'll get 100 landings and 50-70 hours; lots of longer trips and I may get 100 hours on a (main-gear) set. That said, yesterday I put on my 17th set (1800 landings/take-offs) of main-gear tires. But,...a few sets back, I had asked myself "why am I changing out this perfectly good inner tube every time? I'll just wait and change it every 2nd or 3rd set." So I didn't change the tubes; that was my mistake and it almost came back to bite me.

After installing the new tires and old tubes, I started taxiing to check function. WTH? It feels like a freaking wash-board! Maybe they just need to get broken in (yes, a stupid thought, I know). Maybe a wheel nut is loose and I have bearing wobble? Maybe... Well, I was running through all the 'maybes,' all to no avail. So then, I did three test take-offs and landings--and got some really nasty shuddering each time the mains lifted off. Back to the hangar for more evaluation and analysis. Then, 5 minutes after putting the plane away, I'm sitting at my desk 7 feet from the left main, when the tube explodes and the main settles to the concrete in a loud hiss, very nearly scaring the crap out of me! Holy ****! Good thing that didn't happen 15 minutes ago, when I was out there landing and taking off--or tomorrow, on the trip I was going to make up north to Indian country airport KO21.

And you know the culprit? It was that re-used inner tube. You see, last night I did some research and discovered (what most of you probably already knew--but I haven't seen elucidated here) that you are not supposed to use the old tube in a new aircraft tire. Tube use results in the tube growing up to 25% in size. Getting that expanded tube to fit correctly in the new tire--without a dangerous fold or wrinkle--is problematic. A wrinkle finally caught up with me--and almost made for a really bad day. We put new tubes in both those tires this morning and all was hunky dory again.

And here's another little factoid (if you can believe everything on the internet) I picked up during this adventure. You know how bias-ply tires often get flat-spot lumpiness from sitting under load? Well, this is exacerbated during the first 12 hours after a new tire is initially filled with air, because during that time, the tire slowly expands and fills out. So, avoiding that severe initial lumpiness is just a matter of either (1) leaving the new tires and wheels off (totally unloaded) for 12 hours; or (2) Jacking the load off (no pun intended) each main for the same amount of time.

Anyway, that's what I love about aviation: You learn something every day! And from now on I won't be trying to save a lousy 9 bucks, by not putting in a new tube, when I install a new tire on my Sting Sport.

Rich
Last edited by drdehave on Wed Aug 28, 2013 6:34 pm, edited 2 times in total.
Sting Flight (Flying the Sting LSA)
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Jim Stewart
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Re: Close Call--Over a $9 Inner Tube!

Postby Jim Stewart » Wed Aug 28, 2013 6:01 pm

I just replaced my nosegear tube Monday. Replaced the wheelbarrow tube with a real airplane tube.

Here's what I do. Inspect the inside of the tire. Use tire chalk liberally on the tube. Take out the valve core. Put everything together and inflate the tube and see how it seats. Let the air out. Inflate it again. Check for any pinches or problems. If you're good to go, put the valve core back in and inflate to rated PSI. I have lots of tire chalk if you need some.

I haven't had any significant problems once I replaced all the wheelbarrow tubes with airplane tubes.
PP-ASEL, Flight Design CTSW owner.

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FastEddieB
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Re: Close Call--Over a $9 Inner Tube!

Postby FastEddieB » Wed Aug 28, 2013 6:29 pm

Desser shipped me some tire talc with my last order (Monster retreads).

Up until then, pretty much just used baby powder. I can't detect any functional difference.
Fast Eddie B.
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MrMorden
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Re: Close Call--Over a $9 Inner Tube!

Postby MrMorden » Mon Sep 09, 2013 1:32 pm

FastEddieB wrote:Desser shipped me some tire talc with my last order (Monster retreads).

Up until then, pretty much just used baby powder. I can't detect any functional difference.


Baby powder smells nicer. :mrgreen:
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA

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drseti
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Re: Close Call--Over a $9 Inner Tube!

Postby drseti » Mon Sep 09, 2013 1:34 pm

FastEddieB wrote:Desser shipped me some tire talc with my last order


I'm a big believer in tire talc, Eddie. I bought a pint jar from Desser, and shake it on liberally whenever I change a tire and tube.
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drdehave
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Re: Close Call--Over a $9 Inner Tube!

Postby drdehave » Mon Sep 09, 2013 2:32 pm

I've got two bottles of tire talc arriving today. And I plan to use it freely, too, from now on...

However, if you were to use the old tube, and it has grown by 25%, it seems there would still be potential trouble...

I'll go with a new tube and lots of lube.
Sting Flight (Flying the Sting LSA)
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