Hello,  Not having much luck with bars recently. Worn out 3 different makes of 60cm bars in 2 years on saws which are hardly used. Averaging 2 chains before they not longer cut straight. Kox, Stihl and Sugihara all consigned to a nail on the garage wall. I use Aspen bio chain oil. This is fine on the climbing saws and bars up to 45cm but it seems not to give enough lubrication on longer bars. My 500i oiler is on it's max, the saw is always clean and yet barely 2 chains i