I don't know, Rotella-T has been around since before motorcycle standards were ever even thought of. I was using Shell Rotella-T back in 1989 in the diesel truck in 15w40. Rotella and Rotella-T is exactly the same. I suppose just some verbage leaves out the T part, but it works fine either way as there is no difference. Of course standards have changed over the years. Back in 1989 we were in the SG whatever and now SM whatever. Different additives, but it's been known as Rotella-T or just Rotella interchangably for all these years.