Quote:
Originally Posted by Frank Lee
In a straight line, diff gears aren't turning or doing anything at all!
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I think what you meant is that there's no slip when going straight... That doesn't mean there's no rotation or no motion - there's still [at least] 3 points of gear meshing for a car diff - but the planet gear doesn't have any relative angular velocity as the side gears spin about it. That assumes 50/50 load distribution - which is likely not the case (especially with passengers, cargo and/or slightly uneven tire pressure). As duff said - 1-2% for each [helical] gear interface.
Then add the energy to move oil etc. etc. etc.
LSD can increase efficiency a bit - but not too many cars use them....
All that said - I'll take the loss over tire wear
