Tom Ace wrote:
> [email protected] wrote:
>
>
>>Lubricating the chain with hot 90W gear lube works but it is also
>>efficient fly paper, collecting plenty of hardpack between sprockets
>>and on the outside of the chain. Motor oil is far better, but
>>motorcycle chain and chainsaw lubricants are better yet, because they
>>have volatile solvents that allow good penetration for their
>>relatively viscous lubricant. [...]
>
>
> The question wasn't just about 90 weight but about 80 or 90.
>
> Motor oil and gear oil weights are graded on different
> scales (I find this just as inane as how sock and shoe
> sizes are different). An SAE 80 gear oil has viscosity
> comparable to that of an SAE 20 or 30 motor oil.
> See the chart at
> http://www.experimentalhelo.com/eh_oilVisChart_fullT.htm
>
> Is there a significant difference (e.g., presence of volatile
> solvents) between SAE 30 motor oil and SAE 80 gear oil?
>
> Tom Ace
>
Your chart on viscosity is for *100C* temperature, or boiling water (212F).
The bicycle chain at cooler temperatures experiences a different
lubrication viscosity than given by the charts.
I was unable to easily find the viscosity vs temperature data for the
lubricants in question.
Usually, motor oils don't have "volatile solvents" to any large degree,
because they would volatilize and go away when the oil is warm.
I have always found casual discussions of lubrication to be rather slippery.
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