I put a set of Cooper AT3's on my Ranger (towning an A'Van) before a 3 month trip, we did 18,000 kilomtres on them of that we did about 1400 kilometres on dirt and they are well over 50% worn, they have 6mm of tread left. That equates to about 92% on-road and 8% off-road, yet Cooper say they are good for 70/30%, what a crock of ****!!!!
These are the worst wearing tyres I have ever bought, I will never ever again buy these. At $320 per tyre, the pain is not good
And before you get stuck into me, I am anal about tyre pressures, tyre rotation, correct tyre pressures for the environment.
You have probably got 30-40% power and torque on the old D22s and dare I say a bit more mass too.