Where are you Cuzza, what tyres are we talking about on what breed of truck?
I had similar issues years ago on mine but I don't know what you have so wont get specific as it may not be relevant to yours.
In the mean time I went onto another site I frequent and did a search and here is a post that may assist you.
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A guide to tyre wear
If you look along the tread line of the tyre (from the back to the front over the top of the tread.
Wear on both outer edges of an individual tyre, all the way around = underinflation.
Wear on centre section of the tyre, all the way around = overinflation.
Scalloping can be caused by several things and I do not agree with shocks as the main cause. Shocks that are in poor condition will not help the issue but will not be the cause.
Wear around the tyre at differing heights (when looking across the top of the tyre from the rear), so tread is low, then high, then low etc as it goes around the circumference, but is fairly equal across the width, will be what they call static out of balance. This happens when one side of a wheel is heavier than another side. If you stuck a chunk of mud on the tread somewhere, it will cause the wheel to rotate until the mud is at the bottom (when wheel in air). This inbalance leads to an 'up-down' style of movement when driving and will result in vibrations or shudders through the steering if on a front axle, and will resonate through the car if on the back axle.
You can have tyres that are scalloped across the tyre and makes the sections of tread look like its worn like wedges. If this is all the way around and looks similar all the way around, it can be caused by tow-in or tow-out issues (you can tell by looking at the way the 'wedge' goes if its tow-in or out). This type of scalloping can also be caused by loose steering uni-joints, mainly in the drag link that links both wheels, or other steering components that allow the wheels to be pushed or dragged at an angle.
Scalloping that is a little uneven can be caused by dynamic wheel balance issues as the wheel wants to wobble sideways as well as up and down. This is when a wheel has a weighted section more on one side, but off-set from the middle. So if you stuck a weight to the side of you tyre you would get 'dynamic' issues.
This uneven type of scalloping can also be caused by loose wheel bearings.
If you have wear on the inside of the tyre more than the out (all the way around), this is due to a neg camber issue. If in a Patrol, I'd be considering your steering / king pin bushes and /or wheel bearings.
Keep in mind that mud tyres are hard to balance and keep them balanced. It took me 3 goes to get it spot on with my 33's and I have done them again end of last year, and will be doing them again soon as the wobble is back.
I had more than 200g on one side of a wheel when they were new.
Muddies, especially cheaper ones, are hard to balance unless the machine is on the right setting and the fellow knows exactly what he's doing.
If you have the wheels perfectly balanced, you should have no issues.
Tyre pressures generally wont cause real bad vibrations but if the tread was even a slightly different compound in areas (a fraction softer in one location than another) if it was a cheap or dodgy batch, then you will hit a 'soft-spot' each time it rotates. This is fairly unlikely. I'd be considering balance and physical items like steering and bushes.
Last edited by Lieney
Cheers
Chimo