At 06:00 PM 6/2/98 +0100, you wrote:
>snip...made (even fractions of a turn). There are supposed to be 980 turns
every mile,or 9.8 turns in the short distance.
Steve,
Is this correct for all Tigers? I had understood that the Tiger II
speedometer was set at the US standard of 1000 RPM (of the cable) equals 60
MPH.
How do this correlate with the number of turns?
Lets see: 1000 rpm for 1 hr = 60,000 revolutions = 60 miles and
60,000/60=1000 turns per mile. So the reference would be 1000 turns per
mile for most US speedometers.
With 23" tires (varies by tire sizes and air pressure) there are about
5280*12/(3.1416*23)=876.9 rotations of the tire in a mile. With the 2.88
gear ratio there are 876.9*2.88=2525.4 transmission shaft turns per mile.
Now we need the ratio of the speedometer gear to the transmission gear. I
had heard that the nylon
speedometer gears are available in 15, 16 and 17 teeth.
2525.4/ 980 = 2.5769 or 2525.4/1000= 2.5254
15/ 2.5769=5.82, 16/ 2.5769= 6.21, 17/ 2.5769= 6.6
or
15/ 2.25254= 6.659, 16/ 2.25254= 7.1, 17/ 2.25254= 7.547
So I would assume that the transmission gear is either 6 or 7 equivilent teeth.
The Transmission shaft gear is a sort of worm gear, is it possible to have
fractional number of teeth on a worm gear?
Does any one know for sure what the transmission shaft gear tooth count is
for the various transmissions that came with Tigers?
James Barrett Tiger II 351C and others
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