It could be 'tramlining'. A common side effect of many big tyres. On the other hand, is the tyre wear uneven, for example on the inside or outside of the front tyres. Do you hear any knocking or bumping from the front suspension. If you are able, try jacking the front wheels off the ground and try to turn the wheels left and right while someone holds the steering wheel still. Is there any play? Also check for play in the wheels by rocking them from top to bottom.