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#1
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Tire tread wear vs inflation pressure
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/ |
#2
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Tire tread wear vs inflation pressure
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" |
#3
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Tire tread wear vs inflation pressure
Mine invariably wear from the inside out- I'm lucky to get 60 hours on a
set, even with rotating them. |
#4
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Tire tread wear vs inflation pressure
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. |
#5
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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 |
#6
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Tire tread wear vs inflation pressure
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 |
#7
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Tire tread wear vs inflation pressure
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 |
#8
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Tire tread wear vs inflation pressure
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 |
#9
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Tire tread wear vs inflation pressure
90% of the planes in the air have under-inflated tires. Seems to be
systemic. -Robert |
#10
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Tire tread wear vs inflation pressure
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. |
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