I will wade into this even though I will probably regret it later.
Shell Rotella T 5W-40 or T 15W-40 are both good oils, but they are not great oils. As a matter of fact all oils that say they are synthetic are good oils. The only problem with most synthetic oils is that the main component is petroleum oil (Group 3 petroleum oil). Besides Shell Rotella being a diesel engine oil (which isn't bad for our bikes, it just isn't necessarily the best thing), its main component is Group 3 petroleum oil.
I have looked for API test results on Shell Rotella oils and haven't had much luck, so either the oil is very good or it isn't so great and they don't want anyone knowing. I am sure the answer is somewhere in the middle.
Bottom line it is your bike, and your money. If you are spending less than $6.00 per quart for your oil then you are buying a Group 3 petroleum oil product. It might say synthetic, but most of what is in the container is dino lube. Group 4 (PAO)and Group 5 (Ester) synthetic oils are man made and have no impurities in them, which makes them at least twice as expensive as petroleum. Plus almost all true synthetic base stock is made in the USA. So if you are using true synthetic oil, it wasn't being imported from some 3rd world country.
If you are using Shell Rotella oils then change it every 3,000 miles or 4 months. The main reason for this is that all petroleum oils use what is called viscosity Index improver (VI improver) additives, which due to heat and time break down into acids and will promote rusting. True synthetic oil has no need for VI improver additives, since the oils viscosity rarely changes even if half of it is burned off. Just remember in the refining process petroleum oil is only two steps away from Tar.
Sorry, now back to your regularly scheduled program!!
Last edited by tcv; 07/03/2007 8:09 PM.
