Finally I went for Yoko Earth 1 and I am kind of surprised about how much bad situation my earlier tyre were. Other than obvious differences that you feel when you change to new tyres like more comfortable ride and lower noise, there are certain remarkable improvements that I felt. Immediately next morning after change I started my road trip to Jaisalmer. So I had ample opportunity to test these tyres against my earlier experiences as I have done a large part of this section lot of times earlier. The most important improvements is in high speed steering stability and responsiveness, driving on NE 1 was a different and much improved experience now. Also the control on vehicle both in terms of manoeuvring and braking is substantially superior even if I compare it to situation when my earlier B 390 were not so old. I can also feel better fuel economy on highways. So net net key learning for me is to not wait longer and change the tyre earlier than this time. I guess now 40k would be my limit. Overall quite happy with performance after more than 2k km ride with it.