All this talk about tire sizes, rpm's, mph and gear ratio gave me the
perfect reason to take the Tiger out after lunch to compare my actual
numbers versus those calculated by the very nice hokansontrans.xls. I have
a stock 1965 Mark 1 with the LAT-1 Induction Kit, original 2.88 gears, and
original close ratio transmission. 175R70-13 tires which calculate to a
22.64" diameter. At 60 mph the spreadsheet calculates 2600 rpm but my tach
reads 2250. At 70 mph the calculated number is 3000 rpm but my tach reads
2500. At 80 mph the calculated number is 3400 rpm but my tach reads 2900.
The only possible conclusion is that my Tiger has the little known, yet
highly sought LAT 227 Top Loader with Overdrive. I'm thinking about putting
the transmission on ebay with a reserve of $5K or even trade for a Book of
Norman.
Or, since I know my speedometer is reasonably accurate, maybe my tach reads
low by about 500 rpm. That might explain why things are starting to sound
pretty strung out over 4000 rpm. Are Tom and Theo still doing the new
technology tach innards kits?
Dave
B9471930
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