Tire tread wear vs inflation pressure

[Ben Jackson]

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.

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?

--
Ben Jackson AD7GD
>
http://www.ben.com/

[Jay Honeck]

> Are aircraft tires expected to wear evenly from edge to edge?

Yes, but they rarely do.

If you ponder the stresses of landing, turning, and braking on those
spindly little landing gear, it's quite remarkable that they are EVER
aligned properly.

Most aren't -- thus, the funny wear patterns.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Viperdoc[_1_]]

Mine invariably wear from the inside out- I'm lucky to get 60 hours on a
set, even with rotating them.

[houstondan]

coolest tires i ever saw were on my t-dragger- instructor's citabria.
bottom-outside looked like somebody took a rough sander to 'em. just
ground down from flying one wing up down the runway all the tme.

dan


Viperdoc wrote:
> Mine invariably wear from the inside out- I'm lucky to get 60 hours on a
> set, even with rotating them.

[Roger (K8RI)]

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

[Michelle P]

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.
>
> 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?
>
The tires on my Maule wear for the outside in. It is the way the gear
sets. I can turn the around and literally double the life.

Michelle P

[[email protected]]

houstondan wrote:
> coolest tires i ever saw were on my t-dragger- instructor's citabria.
> bottom-outside looked like somebody took a rough sander to 'em. just
> ground down from flying one wing up down the runway all the tme.
>

That's not the wing-down technique wearing the tires; it's the
spring leaf gear that angles the tires when there's little or no weight
on them, and the outside edge always hits first on landing and gets
ground off. We run two Citabrias and three 172s, and the tires get
rotated about halfway through their life to even up the wear and get a
few more landings.
The center tread of most light aircraft tires will wear out
first because of their rounded tread profile. A squared-off profile
like we see on automobiles might wear a little better but would create
more drag, and would still suffer more center wear than an auto because
of the bulge when there's no weight on it.
My biggest gripe with aircraft tires is their out-of-roundness
and imbalance. Even a cheap auto tire that costs less than an aircraft
tire will be closer to round and better balanced. And it won't have
taken a set and have a flat spot after being parked overnight.

Dan

[The Visitor]

Ben Jackson wrote:
> Are aircraft tires expected to wear evenly from edge to edge?

No. Close, but no.

Depending on your plane there may be some alignment information in you
service manual. Or not.


John

[Robert M. Gary]

90% of the planes in the air have under-inflated tires. Seems to be
systemic.

-Robert

[Todd W. Deckard]

The Whittman style leaf gear rely on the tire scrub to dampen the spring
action. You can observe this when landing on a frozen lake
just right, the airplane will pogo a bit as the gear flexes a few times.

[Jay Honeck]

> 90% of the planes in the air have under-inflated tires. Seems to be
> systemic.

That's because 90% of all GA aircraft are stuck with stupid,
1930s-technology inner tubes.

Of all the dumb things in aviation, that seems to be one of the
dumbest. Mary and I fill our tires every 14 days, and it's a pain in
the butt.

If I had a tire like that on my car, it would be classified as a "slow
leak" and be repaired or replaced.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Bob Noel]

In article . com>,
"Jay Honeck" > wrote:

> Of all the dumb things in aviation, that seems to be one of the
> dumbest. Mary and I fill our tires every 14 days, and it's a pain in
> the butt.

Be thankful that you have a hangar where you can do that work. For
those of us on a tie-down, it's even more of a pain.

--
Bob Noel
Looking for a sig the
lawyers will hate

[A Lieberma]

Bob Noel > wrote in news:ihatessppaamm-
:

> Be thankful that you have a hangar where you can do that work. For
> those of us on a tie-down, it's even more of a pain.

Good quality bicycle tire pump makes short order of this "chore" and I am
in a tie-down area.

I have one in my cargo. It has a pressure gauge on it already so when I
attached the air hose to it, I have a readout.

I am surprised at the other responses. I have only replaced my tires every
other year and I have averaged 200+ hours per year with an average of 300
landings per set.

I check the PSI maybe once every other week. I may lose 3 or 4 pounds PSI
between checks.

I use the garden variety Air Hawk $64.00 tire, nothing fancy.

Allen

[Bob Noel]

In article >,
A Lieberma > wrote:

> Bob Noel > wrote in news:ihatessppaamm-
> :
>
> > Be thankful that you have a hangar where you can do that work. For
> > those of us on a tie-down, it's even more of a pain.
>
> Good quality bicycle tire pump makes short order of this "chore" and I am
> in a tie-down area.

well, one neat thing about a hangar is that checking the tire pressure
is a fine rainy day activity. And it's generally out of the wind. Plus,
for folks like Jay whose airplane has wheel pants, r/r of the pants
(wheel pants that is) is easier in a hangar than on the flight line.

--
Bob Noel
Looking for a sig the
lawyers will hate

[The Visitor]

Jay Honeck wrote:
Mary and I fill our tires every 14 days, and it's a pain in
> the butt.


I over inflate 5 psi. Just to streatch things out to a month.

Getting under the wing and taking off that little hub cap, yech.

John

[Marty Shapiro]

The Visitor > wrote in
:

>
>
> Jay Honeck wrote:
> Mary and I fill our tires every 14 days, and it's a pain in
>> the butt.
>
>
> I over inflate 5 psi. Just to streatch things out to a month.
>
> Getting under the wing and taking off that little hub cap, yech.
>
> John
>
>

Has anyone tried the Sporty's hub caps which have the little door to
permit you to check the pressure and/or add air without removing them?

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

[Robert M. Gary]

Bob Noel wrote:
> In article >,
> A Lieberma > wrote:
>

> well, one neat thing about a hangar is that checking the tire pressure
> is a fine rainy day activity. And it's generally out of the wind. Plus,
> for folks like Jay whose airplane has wheel pants, r/r of the pants
> (wheel pants that is) is easier in a hangar than on the flight line.

I have hub caps on my plane that must be unscrewed, a royal pain in the
butt. Since its only about 3 feet between the bottom of the wing and
the ground my 6'4" frame doesn't like crawling under there often. Plus,
since I'm retract I worry about getting the pressure wrong.
I would love to find a tire system that didn't require this all the
time.

-Robert

[Roger (K8RI)]

On 3 Oct 2006 21:16:37 -0700, "Jay Honeck" > wrote:

>> 90% of the planes in the air have under-inflated tires. Seems to be
>> systemic.
>
>That's because 90% of all GA aircraft are stuck with stupid,
>1930s-technology inner tubes.
>
>Of all the dumb things in aviation, that seems to be one of the
>dumbest. Mary and I fill our tires every 14 days, and it's a pain in
>the butt.

As I've said before, spend the money for the new "low leak"
innertubes. They are well worth the money and the time to install.

>
>If I had a tire like that on my car, it would be classified as a "slow
>leak" and be repaired or replaced.

You can do the same with the ones on the airplane albeit the tubes are
a bit more than the ones for cars.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Roger (K8RI)]

On Wed, 04 Oct 2006 19:43:01 GMT, Marty Shapiro
> wrote:

>The Visitor > wrote in
:
>
>>
>>
>> Jay Honeck wrote:
>> Mary and I fill our tires every 14 days, and it's a pain in
>>> the butt.
>>
>>
>> I over inflate 5 psi. Just to streatch things out to a month.
>>
>> Getting under the wing and taking off that little hub cap, yech.
>>
>> John
>>
>>
>
> Has anyone tried the Sporty's hub caps which have the little door to
>permit you to check the pressure and/or add air without removing them?

I keep asking...Why go to all this extra work when for the same or
less money and effort you can replace the old leaky ones with good
innertubes?
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Newps]

Marty Shapiro wrote:

>
> Has anyone tried the Sporty's hub caps which have the little door to
> permit you to check the pressure and/or add air without removing them?

I had them on my 182 and now have them on my Bo. Makes the gear looker
neater.

[Dave Stadt]

"Roger (K8RI)" > wrote in message
...
> On 3 Oct 2006 21:16:37 -0700, "Jay Honeck" > wrote:
>
>>> 90% of the planes in the air have under-inflated tires. Seems to be
>>> systemic.
>>
>>That's because 90% of all GA aircraft are stuck with stupid,
>>1930s-technology inner tubes.
>>
>>Of all the dumb things in aviation, that seems to be one of the
>>dumbest. Mary and I fill our tires every 14 days, and it's a pain in
>>the butt.
>
> As I've said before, spend the money for the new "low leak"
> innertubes. They are well worth the money and the time to install.

I have them and they are a vast improvement and they came free (that's what
the ad said anyway) with the tires from Desser.

>
>>
>>If I had a tire like that on my car, it would be classified as a "slow
>>leak" and be repaired or replaced.
>
> You can do the same with the ones on the airplane albeit the tubes are
> a bit more than the ones for cars.
> Roger Halstead (K8RI & ARRL life member)
> (N833R, S# CD-2 Worlds oldest Debonair)
> www.rogerhalstead.com

[Matt Barrow]

"Newps" > wrote in message
. ..
>
>
> Marty Shapiro wrote:
>
>>
>> Has anyone tried the Sporty's hub caps which have the little door to
>> permit you to check the pressure and/or add air without removing them?
>
> I had them on my 182 and now have them on my Bo. Makes the gear looker
> neater.

Hub caps on a Bo? SACRILIDGE!!

[Roger (K8RI)]

On Thu, 05 Oct 2006 03:43:04 GMT, "Dave Stadt" >
wrote:

>
>"Roger (K8RI)" > wrote in message
...
>> On 3 Oct 2006 21:16:37 -0700, "Jay Honeck" > wrote:
>>
>>>> 90% of the planes in the air have under-inflated tires. Seems to be
>>>> systemic.
>>>
>>>That's because 90% of all GA aircraft are stuck with stupid,
>>>1930s-technology inner tubes.
>>>
>>>Of all the dumb things in aviation, that seems to be one of the
>>>dumbest. Mary and I fill our tires every 14 days, and it's a pain in
>>>the butt.
>>
>> As I've said before, spend the money for the new "low leak"
>> innertubes. They are well worth the money and the time to install.
>
>I have them and they are a vast improvement and they came free (that's what
>the ad said anyway) with the tires from Desser.

I purchased the new tires last winter and the tubes were *extra*.
Guess I bought too soon<:-)) OTOH that flat spot was driving me nuts.


>
>>
>>>
>>>If I had a tire like that on my car, it would be classified as a "slow
>>>leak" and be repaired or replaced.
>>
>> You can do the same with the ones on the airplane albeit the tubes are
>> a bit more than the ones for cars.
>> Roger Halstead (K8RI & ARRL life member)
>> (N833R, S# CD-2 Worlds oldest Debonair)
>> www.rogerhalstead.com
>
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com