From fremont supply:
That will get me a 3.92 gear ratio. I would put the 22 tooth gear on the axle. It is 4.722 inch diameter so it clears everything fine. And put a shaft somewhere using those 2 bearings and a 14 tooth gear paired with the 22 on the axle. Then put a 30 tooth gear on the mid shaft and a 12 on the motor. That won't be an ideal setup but it should work and make changing the ratio a bit easier by just swapping gears on the shaft. This is very close to where 3rd gear is in the car right now so it seems about right. The only bad part is it is going to take a lot more fabrication to get that shaft fit in there somewhere and adding a lot of extra crap under the hood and be a lot more work and expense maintaining it in the future.
The best I can do with a #50 chain direct drive with no mid shaft is a 10/36 gear set so that gives me a bit lower motor RPM but I am not sure if it is good enough to actually work. It would be much cheaper and simpler since it does away with the extra shaft and assorted mess that goes with it. It would just be the 2 gears and a chain.
Code:
at 3.92 here is my rpm/mph
rpm 288 576 1151 1727 2303 2878 3454 4030
mph 5 10 20 30 40 50 60 70
at 3.6 here it is
rpm 264 529 1057 1586 2115 2643 3172 3701
mph 5 10 20 30 40 50 60 70
I have no experience at electric drives but I really can't see how 24 RPM at 5mph is really going to matter that much to the current draw pulling out from a stop.
Also I measured a stock framed metro and a 36 tooth gear will fit the axle without any real trouble, just a dent in the control arm mounting area for clearance. So if the 3.6 or 3.4 ratio is good enough then pretty much anyone could add an electric motor to their car real easily. A kit could be fabricated that would consist of an axle that has the keyway cut into it and a bracket set for the motor. Probably a couple hour job to add to any Metro.