I'm currently using a 15T/48T sprocket combination. I will switch to 14T/48T sprocket combination after the snow melts from the mountain trails.
I made all of my freeway runs at 75-85 mph, which was near wide-open-throttle operation at approximately 5,000 above sea level, fighting Idaho's springtime winds.
Incidentally, please note, I saw a 31 degree drop in oil temperature yesterday merely by cutting a hole in the front fender. This temperature reduction was observed after
my oil cooler was installed with a drilled fender.
Therefore, my oil temperature reduction from stock configuration must be even higher than 31 degrees.
2005 XR650L: Shorai Battery Relocation, Spud Oil Cooler, XR650R C/S Sprocket, Reinforced Subframe, Chain Slipper Roller, Performance Design Lowering Link, Baja Designs Headlight, FMF Hi-Flo Header, ManRacks SD Rack, ManRacks Front Fender Farkle, CST Surge I Front Tire, D952 Rear Tire, Tusk D-Flex Handguards, Uni Air Filter, No-Toil Evolution air filter oil