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Fixed price repairs are based on the assumption that unit/s received
 are
‘original & complete’... a surcharge may be applied to cover
missing  parts etc...  If in doubt send in the unit for inspection
Good  luck with your project’...  Enjoy your classic motoring...
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latest version... click here
Mileage correction
Clocks
Other services
Post & packing
Contact details
Speedos
Rev counters
Jaguar XK 120 ( 1948 / 54 )
561.1 M
Parts Order E-Mail Link
Payment options
Payment options
Payment options
Payment options
JDO Instruments
Classic Car Instrument Repairs ( Est 1963 )
Fixed price repairs for most British & European Classic Car Instruments
48hr service  available... Why pay more & wait longer ! No UK vat
Tele:   01535 603570 / Mobile: 07872 071512
Please check the  FAQ’s page  BEFORE ringing / texting / emailing
WE ARE STILL OPEN  ( for postal work only )
Speedo Calibration... Calculation page

       To calculate the calibration required ( wheel turn method ) use the following formula  
      ( 6336 ÷ A )  x  B  =  TPM ( cable turns per mile )
      A = Circumference of a fitted tyre in inches*
       B = number of speedo cable turns for 20 turns of one wheel ( 10 turns for LSD )

      Typical example :
       A = 80”
       B = 14.5 speedo cable turns

      ( 6336 ÷ 80 ) x  14.5  =  1148 TPM
 
       If using the road test method the following formula applies ...
      ( A  ÷  B )  x  the present calibration = TPM  where A =  your indicated distance  &  B =  true distance

      Typical example :  A = 9 miles & B = 10 miles.. if  the present calibration  is say 1000 TPM
        the required calibration would be ( 9 ÷ 10 )  x  1000  =  900 TPM  
       For TPKM ( cable turns per kilometre ) multiply TPM x 0.621        
       
*Centimetres x 0.393 = inches                                                                Continued on next page
Scimitar GTE
Re-Calibration surcharge
Re-Calibration surcharge
Re calibration surcharge