official SAE viscosity specs, 5w20 vs 10w30 vs 20w50
 

https://www.rx8club.com/attachment.p...1&d=1226414676

i think i'm going to stick with the 20w50, at least given the climate of my area (southeast). and yes I know that the stuff I have highlighted are not the only important statistics on this chart.

ive been using 5w30 but may use 5w40 now. besides when Johnny Tran asked for advice Lance went 40w

I'm using 10w40 right now.

Havent keep up with SAE spec lately, ahh good read.

I know 10w40 will work for NYC. Ahh, :)

Interesting that just moving from a 5W20 to a 5W30 comes close to almost doubling the shear stability.

And the difference between a 10W and a 20W is only 10 degreesC (or about -18F colder) on low temp pumping viscosity.

5w20 r0x0rz !

who cares about bearing wear !? Mazda said they recommend 5w20 !