I have a 12mm ish banana on the left hand side of my frame, wheel to wheel, 1988 troopy, ex rural fire brigade. It was bashed about a bit, but tracks ok, just the inner right wheel bearing gets stuck to the hub a little when changing over. Not too bad considering.
Tyres wear evenly and I...
Maybe a few things.
The age of tyres perhaps, if it was just outside maybe uv, but you have inside too.
How did you check axle housing straightness?
I jigged up something similar to my axle housing, as in this video, with several sized bushes and a barbell. If you can access a lathe even...