FYI
Motive Gear offers gear sets in ratios up to 7.33 for the 9" Ford rear end.
https://www.speedwaymotors.com/shop/differential-ring-and-pinions~14-5-494-10438?facet=l_ratio:48507
Dan
Dan 520-834-4176 I10 and Twin Peaks
On 12/4/2019 2:49 PM, forrest.whitmore via EV wrote:
Electric Vehicle Discussion List mailing list wrote
Finally, there is the efficiency advantage of operating at the motor's
peak
of the rpm-vs-efficiency curve, which also means less of the energy wasted
as heat.
I think you probably want to gear your drive so that your motor is
operating
at its peak efficiency rpm when you're at your typical cruising speed, and
so that the top speed you want doesn't exceed the motor's red line. But
that's not usually the gearing you get with an ICEV factory differential.
That's why most single-ratio conversions I know of have either locked the
stock transmission in a lower gear, or used a custom gearbox.
I expect that a 3.27 final drive with no other reduction would call for
either absurdly small wheels or a large, heavy, low-rpm motor. Maybe
both.
What vehicle are you converting? Are any other final drive ratios
available
for it? Maybe there's a transaxle from a FWD car you could somehow
shoehorn
in?
Thanks for the response David and direction. I worked out the
rpm-vs-efficiency and gearing out in a spreadsheet. A 3.27 diff with no
reduction doesn't work out well at all. I'm going to develop a custom
single-speed gearbox coupled to the rear diff to get the final drive that
works best. Although there's a transaxle for my vehicle, I'd rather optimize
the use of space and gearing in the vehicle.
Forrest Walker Whitmore
--
Sent from: http://electric-vehicle-discussion-list.413529.n4.nabble.com/
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