Quote:
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Standard final is 11/40. Options are 10/40, 12/39, and 13/39
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...or 3.64:1, 4:1, 3.25:1, and 3:1.
Under the old tire labelling system, the 30 x 3 rear tires had an O.D. of 30" for a circumference of 94.2". With 63360 inches/mile we get 673 revs/mile. At 70 mph the wheels go 785.2 rpm.
So at 70 mph:
With std. axle, engine rpm is 2858 rpm;
4:1 - 3141 rpm
3.25:1 - 2552 rpm
3:1 - 2356 rpm
Now here's a few interesting tidbits:
Ford Model T Frequently Asked Questions (FAQ) - The Frontenac Motor Company Brass-Era Automobile Collection
They say the tires are inflated to 75 psi!
They also say 25 mpg is dreaming- more like 10-12.
Dah! NOW I find this:
http://www.nwvs.org/Technical/MTFCA/...orqueSpeed.pdf
and if I'm understanding it right, redline should be considered at about 1600 rpm. Another source says so too:
http://www.popularmechanics.com/auto...46.html?page=6
So without special gears and/or engine mods, 70 mph does seem highly unlikely.
Although with some W.A.G.ing, the EM performance calculator says it should be just able to hit 70 with 20HP!
http://ecomodder.com/forum/tool-aero-rolling-resistance.php?Weight=1460&WeightUnits=lbs&CRR=.00 8&Cd=.34&FrontalArea=22&FrontalAreaUnits=ft^2&Fuel Wh=33557&IceEfficiency=.18&DrivetrainEfficiency=.9 5&ParasiticOverhead=0&rho=1.22&FromToStep=5-120-5
No, I don't have the permalink thing figured out.