List---This is a good site that Bob referred us to which covers speedo
calibrations. Those that have changed their rear tire diameter, diff
ratio, or replaced their tranny with something other than the way it
came from the factory can use the info repeated in the attached, below.
Go to "ratios" or "speed corrections".if you want to see how far your
speedo is off-true.
More to the point...
For the SMITHS "instrument", there is a number down in the bottom of the
gauge face. (My '73 happens to be marked 1120) This number is the amount
of revolutions the drive cable turns when covering one mile. When
covering the prescribed distance of 52feet 9.5inches our cable should
turn 11.2 revolutions, if we have the 1120 markings on our unit.
Some recent changes I've made caused my speedo to be off by 7%. (10.4
revs vs. 11.2) The cost to make it right was $60. I used a repair shop
here in So. Cal.. More info if requested, or check out the article in
the next 6PACK Newsletter.
Dick
http://www.gaugeguys.com/
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