I have a very small (motorcycle) final drive that calls for SAF-XO. There isn't actually a spec, but the re-labeled product is still called SAF-XO. The data sheet I can find is here:
and you'll notice that the kinematic viscosities put it pretty squarely into the 75W90 range. However, look at the Brookfield viscosity: 42,900 cP. The few synthetic 75W90s I've looked at recently are FAR more viscous at -40. Does SAF-XO just have a slug of PPD in it or something?
Red Line's 75W90NS is about the same, though, as is their GL-4 75-90.
So that makes me wonder: What's the difference? Is that low Brookfield viscosity important above freezing (maybe down to 30F or so)? Why is there such a huge difference between Red Line's 75W90 and 75W90NS in terms of Brookfield viscosity? What additive (or lack of additive) makes this difference? Do I care?
Would the RL NS product be suitable for an application like this? Do I just ignore the Brookfield number and get some Mobil1 or something at the auto parts store, or is there some value in sticking with the SAF-XO?
BTW, Red Line recommends their Shockproof Heavy. That doesn't seem equivalent at all, but maybe they have other experience that leads them to that recommendation.
Appreciate any thoughts, and particularly informed comments.
and you'll notice that the kinematic viscosities put it pretty squarely into the 75W90 range. However, look at the Brookfield viscosity: 42,900 cP. The few synthetic 75W90s I've looked at recently are FAR more viscous at -40. Does SAF-XO just have a slug of PPD in it or something?
Red Line's 75W90NS is about the same, though, as is their GL-4 75-90.
So that makes me wonder: What's the difference? Is that low Brookfield viscosity important above freezing (maybe down to 30F or so)? Why is there such a huge difference between Red Line's 75W90 and 75W90NS in terms of Brookfield viscosity? What additive (or lack of additive) makes this difference? Do I care?
Would the RL NS product be suitable for an application like this? Do I just ignore the Brookfield number and get some Mobil1 or something at the auto parts store, or is there some value in sticking with the SAF-XO?
BTW, Red Line recommends their Shockproof Heavy. That doesn't seem equivalent at all, but maybe they have other experience that leads them to that recommendation.
Appreciate any thoughts, and particularly informed comments.