On Saturday, August 19, 2017 at 8:21:54 PM UTC-4, Bram van den Heuvel wrote:
Given ,
trader_4 wrote:

Yet some gear head
chimes in that "if you can't afford to buy some vacuum hose at BMW,
you shouldn't own the car". You can get silicone hose of the right
diameter for less than $1 a foot.

And when it comes to fluids, some of these gear heads must think that
every manufacturer has their own refinery or chemical factory.

I'm going to agree with you that they say a LOT on those forums that "if
you can't afford to pay X for Y, then you shouldn't own the car".

But what they fail to understand is that a question ASKING what's different
about Redline MT-90 75W90 GL-4 gear oil that makes it worth twice the price
of some other 75W90 GL-4 gear oil is NOT a question about price.

It's a question about what's different besides price.

All they see is "price" because everyone understands numbers.
What they don't see is the question about what is different that warrants
that price.

Sometimes the answer to price performance questions is that the performance
merits the price while other times there's a lot less performance than
there is price.

It's a ratio - but without knowing what's different - nobody can make an
intelligent decision on the price-to-performance ratio.

I'm not sure I understand yet what's different in the
Redline/Amsoil/RPurpal 75W90 GL4 because I live in a warm state where the
75W isn't my issue but the 90 is.

90 weight is 90 weight.
If it's 90 weight for more years, then that's OK.
If it's 90 weight at tremendously hotter than normal, then that's OK.

But that was the question, which I now can hone because I didn't know that
the expensive oils were synthetic.

If a synthetic oil "lasts longer" at 75W90, well, that's worth something.
I'm only asking what's the difference.

That's the biggest difference, that synthetic last longer and you can
go longer between oil changes. BMW uses synthetic and was at 15K for
oil change interval for years. More recently they backed down to 10K,
presumably because they decided they were pushing it too far.