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Good  luck with your project’...  Enjoy your classic motoring...
Fixed price repairs are based on the assumption that unit/s received
‘original & complete’... a surcharge may be applied to cover
missing  parts etc...  If in doubt send in the unit for inspection

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Mileage correction
Other services
Post & packing
Contact details
Rev counters
Jaguar XK 120 ( 1948 / 54 )
1109.1 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: (UK)  01535 672125 (2 lines)  Mobile: 07831 886545
Please check the  FAQ’s page  BEFORE ringing / emailing... thank you
Continued from previous page

     To calculate the required calibration if your car is not assembled
       use the following formula... ( 6336 ÷ A ) x B x C = TPM ( cable turns per mile )
       A = Circumference of a fitted tyre in inches
       B = Differential / Axle ratio   
       C = Number of turns @ the ‘speedo output’ on the gearbox for 10 turns of the ‘prop shaft output’

      don’t forget to take any ‘RIGHT ANGLE DRIVES’ into account e.g. Some drive units are not always 1:1 !

       Typical example :
        A =  80”... B = 3.9  &  C = 3.84

      ( 6336  ÷  80)  x  3.9  x  3.84  =  1186 TPM

       For TPKM ( cable turns per kilometre ) multiply TPM x 0.621     
*Centimetres x 0.393 = inches                                              Return to previous page
Re-Calibration surcharge
Re-Calibration surcharge
Re calibration surcharge