All I will say about this is. Just because "they" made a chart, does not make it fact, or true. Used to be we could say "you can research the world flat, don't make it flat" Now people believe that. I will continue to use my old fashioned 30 wt and be happy in all weather.
flat earth is fairy tale people who cant handle basic science existing lol
Motor oils and their science is 1) very researched, very competitive, very regulated, and best of all, very profitable
Heres an easy way to understand this discussion
go find 3 quarts. 0w-30, 10w-30, and then sae 30 of the same brand, type if you can.
Go put them either in a really cold freeze for a long time, or use a cold stretch outside and just wait till its staying that temp long enough they all are that low temp, then open each one and pour a little into a container from each
You will notice the one just about
doesnt pour and thats the SAE 30. (assuming its like -20, -15, -10 outside)
then you will notice there will be one that pours fastest, 0w-30
then you will notice one that doesnt flow well but way faster than the sae 30. 10w-30.T
The biggest issue with the SAE 30 part that isnt a conspiracy to get you(BTW sae 30 can bethe same price often as any other quart viscosity in my experience. so who they fleecing.
Anyway, the sae30 is detrimental the most for 1) crank speed 2) engine first starts up, ok, well if you have a non moving fluid that has to be pushed and beat up by moving parts to heat up enough to actually travel through the engine, you will experience more wear ever time that occurs. Cold start up. Most engine wear comes from that time.
Hydraulic lifters? someone may not have working valves as they should if its really bad bebcause of temps and stuff. starting may be a bitch then