back to AMGBA website home page or AMGBA Photo Gallery or AMGBA Club Blog
Subscribe in a reader


Join or renew today and receive a free t-shirt or tech CD, see details in the join the club section at www.mgclub.org!

Author Topic: Overdrive speedometer adjustment  (Read 4833 times)

0 Members and 1 Guest are viewing this topic.

december2007

  • Message Board Member not current AMGBA Club Member
  • **
  • Posts: 11
Overdrive speedometer adjustment
« on: December 05, 2007, 03:55:40 PM »
I have an '80 B which has an overdrive unit out of an older MG. It is one for a 76 and older. My speedo does not work correctly now. What can I do to get it correct? Seems like everyone talks about recalibrating my existing speedo. Could I not change out the speedometer from an older B? Thanks.
Steve Ray

amgba

  • American MGB Association
  • AMGBA Club Administrator
  • *****
  • Posts: 543
  • American MGB Association
    • American MGB Association
Re: Overdrive speedometer adjustment
« Reply #1 on: December 05, 2007, 04:16:31 PM »
Dear Steve,

The earlier B speedo unit is a different size and look as well as calibration.  You could probably get it to fit, but it won't look match the rest of the gauges on the instrumnet panel.  That's why everyone talks about recalibration of the existing unit as the way to go.

Truth is, if you've changed the tire size from stock the speedometer is not reading accurately anymore and should be recalibrated to match the car.  As an example, if you are using 185/70-14 tires vs. the original 155/78-14 tires, this amounts to about a 5% difference in the reading, or seeing 57mph on the speedomoter at an actual speed of 60mph.   This would be a good oportunity to correct the calibration and refurbrish the workings.

I hope that helps you.  Good luck.

Art
American MGB Association
website: www.mgclub.org
email: info@mgclub.org
ph.: 773-769-7084
fax: 773-769-3240

North America's oldest and largest club for all MGBs, MGB-GTs & Midgets.  A nonprofit organization founded in 1975 and offers color magazines, emagazines, technical advice, member recommendations on service shops, registration of your MG, a tradition of service & FREE member classified ads that appear in the magazine & on the website.


 

   back to AMGBA website home page or AMGBA Photo Gallery or AMGBA Club Blog