My experiance with TR2,3,4,6 is that the speed for a car with a
3.7 rearend in overdrive is 2400rpm = about 60mph depending on tire size.
In direct it is 3000 rpm = 60 mph.
A 4.11 rear ratio will go (3.7/4.11) of these speeds. Thus 2400 in
overdrive with a 4.11 rearend = about 54 mph.
Since the speedometer cables of overdrive TRs are about half again
longer then in cars without overdrive, And because they snake all over the
place, their life expectancy is anywhere from 9 hours to 9 months in daily
driving. Triumph however came up with a typicaly British solution to this
broken speedo problem: In 4th gear without the overdrive the needles on the
speedo and tach always point in exactly the same direction (with a 3.7 diff)
By glancing at the guages you will see that 2 (k) on the tach is at the
same position as 40 on the speedo. 3 (k) the same as 60, 4 (k) == 80
and so on. Even when the speedo is not working (most of the time) a
glance at the guages will tell you exactly how fast your going.
ANOTHER TRIUMPH OF lbc ENGINEERING ;^)
/Dick
Your mileage may vary
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