How long do airplane tires last?

[digits_]

In a private plane that doesn't fly much, but is hangared, how long does a tire generally last?

The amount of flying time and landings is likely irrelevant for such a situation. I'm more wondering about the age of the rubber. Basically when will a tubeless tire start leaking, or when will a tube start to rot such that the valve stem starts leaking. (those seems to be the most common failure modes on old tires, but I just added them as an example).

Is there a rule of thumb when you should change them?

And on the same note, does anybody have the details of the air michelin/condor tire codes?
Internet tells me:

Michelin (Air, Aviator and Condor)

Michelin aircraft tires are marked with a ten-digit serial number that also represents the year and Julian date that the tire was produced. Character one represents the last number of the manufacturing year; the next three numbers indicate the Julian day and the remaining six characters are related to decade of production, manufacturing facility and production number. For example: 9211P0025 (9) is for 1999, (211) is the Julian day - 29 July, (P) pertains to the facility and decade, 0025 is a unique production number. For more information see https://aircraft.michelin.com.

Source https://iflyamerica.org/how_old_is_this_new_tire.asp

But I'm trying to figure out what all the possible facility/decade codes mean. P is explained here, wondering about 'S' in particular. Google came up empty.

[ahramin]

30+ years ... if kept inflated. If they are sitting around at 10 pounds most of the time and only inflated at annual, not nearly so long. Even without wear and UV damage most tires don't last more than seven years because of neglect. I would never change a tire by rule of thumb. Change it when it is no longer serviceable, not before.

The good news is that it's easy to determine if a tire is serviceable or not since it's a visual inspection. Here's one guide:

https://www.goodyearaviation.com/resour ... e-2020.pdf pages 26-35.

[lownslow]

I have a set that probably haven’t been made in 80 years or more and they’re good enough.

[digits_]

Thanks, that's a lot of useful info.

What about tubes specifically? I doubt they would last 30 or 80 years. I've had 3 flat tires in private planes, and it was always the tube valve stem that was leaking. Seems to be the weak spot. They are not overly expensive. If there's any data that would suggest a significant higher chance of failing after X(X) years, it might be smart to change them preventatively.

[photofly]

Thanks, that's a lot of useful info.

What about tubes specifically? I doubt they would last 30 or 80 years. I've had 3 flat tires in private planes, and it was always the tube valve stem that was leaking. Seems to be the weak spot. They are not overly expensive. If there's any data that would suggest a significant higher chance of failing after X(X) years, it might be smart to change them preventatively.

All the flats I've had have been because the tube split at the seam; no problems with the valve stems.

More often I toss the tube when the tire is bald.

[digits_]

Thanks, that's a lot of useful info.

What about tubes specifically? I doubt they would last 30 or 80 years. I've had 3 flat tires in private planes, and it was always the tube valve stem that was leaking. Seems to be the weak spot. They are not overly expensive. If there's any data that would suggest a significant higher chance of failing after X(X) years, it might be smart to change them preventatively.

All the flats I've had have been because the tube split at the seam; no problems with the valve stems.

More often I toss the tube when the tire is bald.

When instructing or flying commercially I agree the tire wear was the limiting factor. But from my -admittedly limited- sampling on planes that don't fly much, it's the tube that causes issues. Trying to figure out if that's true or if it was just coincidence.

[lownslow]

I’ve flown on some pretty cruddy looking rubber and I feel like it’s the tube that’s doing the lion’s share of the work. Those I replace as needed and if the tire looks good it stays.

Disclaimer: I run wicked low pressure (well under 10psi) and I suspect the tubes move around somewhat in operation which leads to them developing leaks. Never had one let me down in motion bit sometimes I open the hangar to find the plane with a flat. I fly off turf and don’t use brakes, there is no tread on my tires to keep track of.

[PilotDAR]

I had more than 20 years for my 150, hangared and flown off grass most of the time. I've had less life out of tubes recently...

[photofly]

When instructing or flying commercially I agree the tire wear was the limiting factor. But from my -admittedly limited- sampling on planes that don't fly much, it's the tube that causes issues. Trying to figure out if that's true or if it was just coincidence.

I agree it's the tube that causes the problems - I guess it's about 50:50 whether the tube makes it to the wear life of the tire, but the problems I've had have been splits in the seam and not the valve stem. Perhaps it's the quality of my landings, or lack of it...

[SeptRepair]

Cost of parts in general aviation are rising significantly.

The tube life seems to be hit and miss. The cost of tubes now are as much as the tire itself. A standard tire and tube replacement for a 172 for example, using the cheapest options, would be about 290-300$ combined. Add tax and one hour labour to change it, your up over 500$. For one freaking tire!

I try to keep my customers best interest at heart and dont automatically change a tube with the tire. I use talc when assembling as I think that helps extend the tubes life. Most tube failures I have seen are the tube splitting at the seams. I think its the diminishing quality by the manufacturer that is seeing the rise in more tube failures. Customer can weigh in if they want a new tube with a new tire.

As for a tire, I change it when obvious cords are showing. If its cracked from sitting in the sun, then it is up to the owner/operator to make that call if they want it changed. Then again so is the decision to change a tire if the cords are showing. I just do as instructed, but will give opinions.