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Why do overdrives work?
What I mean is... I don't see the point of gearing a transmission 0.70 to turn a 4.10 rear axle into a 2.87 rear axle. Wouldn't it make more sense just to have a a 1:1 connection with a 2.87 rear axle, and lower first gears to compensate? The efficiency of every gearset saps power some, i'd think something overspeeding would sap more power than 1:1 ever would. Playing with my lego sets as a child with the gears, any time I tried to make a larger gear, turn a smaller gear (so it went faster than 1:1 rotation on the input) had horrible resistance compared to anything equal or slower output speeds, so intuitively it feels wrong.
Cars like the Dodge Viper have a 0.50:1 OD ratio in some of the 6 speed transmissions. Large trucks had similar, some had double overdrives, or possibly even triple i've heard of with the brownie box at the very end after an overdrive transmission and an additional OD range selector, before hitting the two speed axle or the brownie box in the rear for slow speed mining off road crawling speeds up in michigan. Wouldn't the most efficient connection be the least # of gears to sap power?
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