Agree on the lower cost dino oils. I've had a number of bikes over the past 30 years and have gone through many different types of oils - synthetics and others. My choice are the premium quality name brand diesel engine oils such as Shell's Rotella T 15W-40. This product - as an example - was made up at one point of 25% addpak and viscosity index improvers - the other 75% was "high quality" base stocks. I don't know how it's blended now but it's always treated me with the smoothest shifting right up to oil change time at a cost that made changing oil a pleasure