Uneven wear on tires

[xander75]

not sure if its been said already or you been give that pointer, but I found very good results with the goodyear flight special II (4ply)
uneven wear can also come from inaccurate pressures on the tire(s). On the arrow I have its 30 nose and 27 mains, for whatever reason, not persistent leaks, they lose pressure over time, especially on hot days.
Also passenger and fuel loading on a low pressure tire on a heavier loaded side can give you some extra wear as well especially on warmer days and hard landings/letting her sit on the ramp in the summer heat...
xander

 

[kshaw]

A quick way to check your wheel alignment is to use a large T-Square and hold the T-square against the wheel and then look down the scale portion of the T-square like you aiming a firearm. It should be pointing about 2 inches in front of the opposite wheel. If not, that wheel is out of alignment. Do the same on the other wheel. You adjust alignment by adding or reducing washers on the strut. Some of the older maintenance manuals had a good description of this process but the newer manuals omitted it altogether.

 

[Dan Thomas]

A quick way to check your wheel alignment is to use a large T-Square and hold the T-square against the wheel and then look down the scale portion of the T-square like you aiming a firearm. It should be pointing about 2 inches in front of the opposite wheel. If not, that wheel is out of alignment. Do the same on the other wheel. You adjust alignment by adding or reducing washers on the strut. Some of the older maintenance manuals had a good description of this process but the newer manuals omitted it altogether.

Best to consult the manuals to see what the toe-in or -out should be. It varies considerably between models. Cessna manuals have good stuff on wheel alignments for their airplanes.

 

[kshaw]

Best to consult the manuals to see what the toe-in or -out should be. It varies considerably between models. Cessna manuals have good stuff on wheel alignments for their airplanes.

Both wheels have to be parallel. The 2" I use is to allow for the two inches width of the T-square I was using.

 

[Dan Thomas]

Both wheels have to be parallel. The 2" I use is to allow for the two inches width of the T-square I was using.

As I said, the wheel alignment is specified in the service manuals, and it varies between models. Mechanics should not make assumptions.

The '69-'76 C182 manual:



'76 172:



C206:



'69-'76 C180 & 185:



PA-28:



Aviation is full of amateur "advice." One old bit of it says that trikes need to be toed in some, taildraggers toed out. But where does any manufacturer specify generalizations like that? Where they specify toe-in, it's very little (up to a sixteenth of an inch for Cessna trikes, up to almost 3/16" for some, and up to an eighth for the taildraggers), and nowhere is toe-out specified. Rolling friction will twist the legs from a toed-in position to a neutral position, and in the taildraggers the weight, in a tail-low attitude, will also twist them outward. In the PA-28, the brake disc is the reference, and a half degree across that works out to about a sixteenth.

A fellow bought a Cessna 170. In getting checked out with an instructor, they found the thing nearly uncontrollable on the runway. They brought it to our shop, and I found the gear massively misaligned. I spent a long time sorting it out with the various shims, got it right, and after that it was completely tame, at least as tame as a taildragger can be.

When all else fails, read the instructions.