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Fixing wheel camber

WingnutWick

Well Known Member
Hello all,

My RV-8 gets pretty significant wear on the inside of the wheel, leaving the outside of the tire tread nearly untouched. I am wondering what the fix is for this to get a more even wear and straight camber. Is this by design or is it supposed to be relatively straight?

Thank you.
 
Shims

You’re probably going to have to shim the axles. I encountered a similar problem, and I started with the 1.00 shim. I’ll know if i picked the right shim as the tires wear. Link below for Grove shims.

Some people remove the tires and flip them in order to get more life out of them.

https://www.groveaircraft.com/accessories.html
 
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Without seeing pictures, if both tires are wearing symmetrically on the outer edges, this is fairly normal for an 8 due to the way the gear hangs. The solution is to flip the tires on the wheels. I normally get 400-500 hours out of my tires. I flip them at about 200 hours. This has worked well for me during my 13 years and 1800 hours of flying mine.
 
Its more likely that you have some toe-out than excessive camber. All RV's and even certified aircraft have some camber. Depending on the type of gear toe affects camber and vise-versa as the tail comes up or down. The easiest first check is to clamp two four foot angles to the brake discs with the tailwheel on the ground and measure how much toe-out you have. Then shim the axles appropriately to get zero toe in a 3-point attitude.
 
Plus one for RocketBob.

I have zero toe-in, and my tires wear almost perfectly even. I do not bother to rotate them. When the outer tread grooves are gone, I replace the tires. By "outer" in this case, I mean the grooves closest to the sidewalls, both on the inboard and outboard side of the tire.
 
It seems like there is a variety of what people experience with the wear on their 8s. Some wear evenly, some wear on the outboard side, and mine wear aggressively on the inboard side of the wheel to the point where the outboard treat is nearly untouched when the inboard side of the wheel has significant wear. It was mentioned above that most 8s wear on the outside??? That would certainly make mine an outlier. I have been rotating the tires to get more life out of it but I can't help but think it would be nice to not have to do this as well as possibly a little better high speed ground handling perhaps were they even.

I guess I'll start by figuring out if this is a matter camper or toe out. Hmmmmm
 
“better high speed ground handling” and wear on the inbound side of both tires, points pretty strongly at a toe OUT issue. Any toe out will make the airplane dart left or right and the more weight applied can increase the toe out. Check that first as described above.
 
Toe Out vs. Toe In

“better high speed ground handling” and wear on the inbound side of both tires, points pretty strongly at a toe OUT issue. Any toe out will make the airplane dart left or right and the more weight applied can increase the toe out. Check that first as described above.

This seems to be an age old debate with tail-wheel aircraft. My experience is exactly the opposite of what you say. Very slight toe-in (~.1 degree each side) resulted in somewhat unpredictable and "darty" ground handling during landing roll-out. Adjusting this with .25 degree shims towards toe-out resulted in ~ .1 degree toe-out per side and very predictable handling during roll-out. This was verified by 2 pilots.

Even with the slight toe-out, my tires still wear on the outer edges faster than the middle or inside edges. I think this is largely due to the fact that the stock gear has positive camber when unloaded, i.e. when the wheels first touch down and scrub the runway.

Skylor
 
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Interesting. Well seeing as my tires wear heavily on the inside and I definitely get some darting left/right (on touchdown to rollout predominantly) then I think that I will at least start by finding out what the toe IN/OUT situation is on them and go from there. Will report back!
 
skylor;1479913 Very slight toe-in (~.1 degree each side) resulted in somewhat unpredictable and "darty" ground handling during landing roll-out. Adjusting this with .25 degree shims towards toe-out resulted in ~ .1 degree toe-out per side and very predictable handling during roll-out. This was verified by 2 pilots. Skylor[/QUOTE said:
THIS!

Think of it like this. With toe-in, if the airplane starts to drift left more weight is put on the right wheel. Because the right wheel is toed-in, the airplane is pulled further left. With toe-out, if the airplane starts to drift left more weight is put on the right wheel. Because the right wheel is toed-out, the airplane is pulled back toward straight.

With the standard gear on RV-3, -4, -6, -7, and -9, the recommendation is for the gear to be straight when completely unloaded. By design, this gear produces a slight toe-out when loaded.
 
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