PLEASE READ - RE:confused about synthetic gear oil

[Livolsi, Stephane]

I hear you and agree except for one thing..

I did a bit of research about oils (synth and regular) before deciding on
the amsoil 80W90 GL4 synthetic.
I am sure that somewhere, I read that synthetics maintain their viscosity
range over a broader range of temps.  Isn't that correct?

So a non-synth 80W90 will have that range of viscosity over temps of say -10
to +50 C (pulling #'s out of a hat)
a synth 80W90 will have that range of viscosity over temps of say -30 to +70
C  (also pulling #'s out of a hat)

I could be wrong, I'm willing to learn...

Stephane

> ----------
>
> When it comes to how "thick" an oil is, the viscosity is the measure of
> the "thickness". The use of two numbers in the viscosity ratings of oils
> such as 15w40 shows the range of the oil's viscosity. So a conventional
> multi-grade gear oil with a viscosity rating of 75w90 is the same
> "thickness" as a 75w90 synthetic gear oil, only the synthetic oil will
> break down slower. The higher the viscosity rating numbers (especially
> the second one of the two), the "thicker" the oil is. Now, one thing
> that people should also keep in mind is that different oil companies may
> use different processes and include different detergents and additives
> in the oils which may make two oils of the same viscosity seem
> different. Also new oil will perform differently from used oil so there
> may be a change in apparent "thickness" after a fresh oil change.
>