Question about Rotella 5W40

[Sidekick]

The 5w40 versions always break down in grade faster than the 15w40 versions in the UOA’s I’ve had come back.

Not relevant for full synthetic oil as I learned tonight, thank you for mentioning it
In UOA, the Rotella T6 5W-40 match the T6 15W-40 for grade retention (Shell labs).
The HTHS (High Temperature High Shear) looks to be the Key, both 5W-40 and 15W-40 meet or exceed the same HTHS spec (Shell labs & oildepot.ca)

 

[Igofar]

So says the people who sell and market it
Shell also claims their stuff is JASO certified.
If you want to use it, use it. Your bike, your choice.
If you don't like it, try something else.

 

[Igofar]

I think we could come up with two other kinds of people. Everyone with the same opinion as mine, and everyone else who is wrong.

Maybe we could get the emotion level down some?

Chris

No emotion from this camp, as I don't care what oil folks use.
I just threw out some information based from my experience.
We could probably add two more kinds of folks to that group. Those who've torn down and inspected many engines, and those who just repeat what they read on forums.
I'm out of this thread.

 

[Sidekick]

So says the people who sell and market it
Shell also claims their stuff is JASO certified.
If you want to use it, use it. Your bike, your choice.
If you don't like it, try something else.

I know, facts don’t always sit comfortably.

 

[Joeywhat]

Insofar as the viscosity rating goes, I never understood why anyone would stray from one of the viscosity ratings that the vehicle manufacturer has specified for a given vehicle.

Probably because there's been numerous cases of manufacturers changing oil ratings due to engine issues, largely because they wanted to meet CAFE standards and were using oil that was too thin in order to get under said standards.

The OEMs aren't interested in engines lasting as long as possible, they're interested in meeting the MPG standards set forth by the countries they're selling in, and the engines lasting at least through the warranty period. That's it. This idea that these engineers making these decisions are doing so based on anything outside of the powertrain warranty and emissions/mileage standards is absurd and wishful at best.