Tire tread wear vs inflation pressure

On Mon, 02 Oct 2006 15:47:11 -0500, Ben Jackson wrote:

I discovered when I bought my plane that pretty much every aircraft tire
I had ever seen was underinflated. The manual calls for 42psi in the
mains on my plane, and if you can see even the slightest sidewall
squishiness they're down in the low 30's and at the end of a month they're
down below 30psi. Just the result of 1960s rubber technology, I guess.

I keep mine aired up at least once a month because otherwise it becomes
very hard to push the plane back into the hangar over the lip of concrete
and the door track.

Spend the money for the new long life inner tubes they are making now.
I put them on the mains and I've only had to pump them up once in the
last 6 to 8 months. The nose gear still has the old style tube and
that sucker is a bi-weekly pump.


However, I've noticed that the treadwear (not all due to me, I'm still on
the tires that were on the plane when I bought it) is greater in the center
of the tire, which on a car tire would be consistent with overinflation.
Are aircraft tires expected to wear evenly from edge to edge?

I fly in all kinds of weather, but one thing I do is land as slow as
the airplane will let me. Once you learn the airplane the Bonanzas and
Debonairs are some of the easiest to land airplanes out there.

I normally get very good life out of the tires even with all the
landing practice and particularly soft field. Typically I think I get
on the order of 500 hours plus out of them. I really need to go back
to my log to see how long the previous set lasted. I've put over a
1000 hours on the Deb and I put this set on last winter and they are
the second set. The only reason the other set was changed was due to
a screw up on my part. I was doing short field landings in some
pretty strong cross winds. I had my feet a bit too far up on the
pedals and flat spotted the left tire on the mains. Not enough to
make it a weak spot, but enough to make it really vibrate. I'd guess
there were at least another 300 to 400 landings in there.

With all the practice I do in that nearly 3000# airplane I'd guess I
get 300 plus landings a year on it. If I haven't flown for a couple
of weeks I head to the practice area and spend an hour doing stalls
(approach, departure and accelerated) I work the accelerated in with
the steep turns (60 degrees), do some turns on a point, around a
point, and then S-turns back to the airport area where I'll spend
another 45 minutes to an hours doing every type of landing I can think
of and try to get in at least a couple on the runway with the most
cross wind.

But to reiterate, those new tubes are worth the money!

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com