What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Inner tubes, age, brands and unexplained holes

After 3 years & 700 landings a tire tube went flat, with no clear explanation. There's a 1/8" long crack/hole on the inner tube sidewall, but no marks on the tires sidewall (inside or out). That leaves me to wonder about tube/rubber age, manufacturing defects, brands and so forth. Should I be worried about the other 2 tubes? Should I just replace them all? Does any brand actually stand out in the case of tubes?
 
What tire pressure are you running? I used to run pressures under 30# to help eliminate gear shimmy but ran into unexplained problems like you described. Holes on the side of the tubes and nothing notable inside the tire. I always use plenty of talc. After much discussion with friends and research, I think that the lower pressure can cause some excess "flexing/movement" between the tube and the tire that seems to cause this. It is like little cracks and pin holes develop in the tube sidewalls.

I have increased my pressure to about 38# and hope I have solved the problem. I run Desser Elite II tires which I really like and are realatively "stiff". I am not currently having any significant shimmy problems with the higher pressure.
Keith
 
An RV 12 should be fine with the factory specified air pressures, if the tires were originally installed properly.
Aircraft tires with tubes need lots of lubricant between the tube and the tire to reduce friction during sidewall flex. That is what tire talc is for. I recommend a heavy coating on the entire inside of the tire and after just slightly inflating the tube put a heavy coating on it as well before inserting it in the tire.
 
...what tire talc is for. I recommend a heavy coating on the entire inside of the tire and after just slightly inflating the tube put a heavy coating on it as well before inserting it in the tire.
That is exactly what I did when I rotated tires a year ago, and--at the time--there was also white powder present from the previous assembly. That previous stuff could have been corn starch for all I know.

What about rubber age, and/or visible signs I should be alert to?

Hypothetically, if you had to choose a brand of inner tube for use on a Mars rover, which would it be? I realize that's silly, but it illustrates my re-educated sense of cost.
 
That is exactly what I did when I rotated tires a year ago, and--at the time--there was also white powder present from the previous assembly. That previous stuff could have been corn starch for all I know.

What about rubber age, and/or visible signs I should be alert to?

Hypothetically, if you had to choose a brand of inner tube for use on a Mars rover, which would it be? I realize that's silly, but it illustrates my re-educated sense of cost.

We use the same tires and tubes on our demonstrator fleet as we supply in the kits. We have always gotten good service life from them with no tube failures like you describe, but we do fly a lot of hrs per year so age related failure is very unlikely in our case, but could be a real problem (in though I don’t have any specific knowledge regarding that).
 
What tire pressure are you running? I used to run pressures under 30# to help eliminate gear shimmy but ran into unexplained problems like you described. Holes on the side of the tubes and nothing notable inside the tire. I always use plenty of talc. After much discussion with friends and research, I think that the lower pressure can cause some excess "flexing/movement" between the tube and the tire that seems to cause this. It is like little cracks and pin holes develop in the tube sidewalls.

I have increased my pressure to about 38# and hope I have solved the problem. I run Desser Elite II tires which I really like and are realatively "stiff". I am not currently having any significant shimmy problems with the higher pressure.
Keith

I'll second this. I used to run 33-35#, but then got the same holes on *both* tubes (L and R) within a couple of weeks of each other. Same discussion, now running 40-42#.

I think the lower pressures are almost certainly the cause here, due precisely as you noted the flexing and movement that the lower pressures allow.
 
Non Premium Tubes

I did my assembly on kit shipped tubes with plenty of talc and ran 28-32 psi.

Got a flat with no visible hole in tube. I could see where the air was leaking from the sidewall when submerged, but it was coming from a pinhole so discreet that my eyes just couldn't see any damage.

Airstop tubes have given me less problems.
 
My bought built RV-6A got a flat on the front after 4 weeks sitting at the avionics shop.
I wanted to blame their parking lot to start with. Why not it sat there for 4 plus weeks and was fine. Pulled it out of the shop to run engine and set up the HDX. Next day it was flat. Go figure. Luck of the draw.
Drove down, pulled wheel and tire only to find the side wall was scrubbed real good and that is where the leak was. Put on a patch cause no tubes were available on Friday afternoon. Still doesn't leak after 8 months.
I run all tires at 45 PSI and have no problems.
Scuffing is from low tire pressure.
Seen it 55 years ago in the old tubed tires and see it now.
My luck ran out on that deal. At least I've been a mechanic for 55 years so have a handle on the situation.
Oh ya, I now have three new tires and tubes in my hangar so it probably won't ever happen again. I like fresh rubber. Smells good.
Art
 
Back
Top