speedo

[Bill Toppin]

Hi everyone
I would like to know if there is a way to calabrate my
speedometer. It seems to be off about 10 mph according to
my gps the car is a 62 BT7 MkII Tri carb thanks for any help Bill

 

[Dave Russell]

Hi Bill,
If you really want to try fixing it yourself here is some help:
https://mgaguru.com/mgtech/dash/st101.htm

If you send it out, this is a good, fairly near by, place:
https://www.nisonger.com/
D

 

[dklawson]

I work on tachs and speedos periodically at home. You can do this yourself if so inclined. I'd start with reading through this PDF article:
www.sterlingbritishmotoringsociety.org/ files/SmithSpeedoRepair.pdf

I have found that most the gauges I work on that are out of calibration read "low". I'm basing this on supplying them the RPM they need to read 60 MPH... changes in final drive or tire size are beyond what I work on. I've found that following the advice in the PDF document above you can add rare-earth magnets to restore the calibration to many older instruments.

If you're squeemish about opening up your speedo and running your hands over its internals, try Nisonger, Palo Alto Speedo, or APT instruments.

 

[Bill Toppin]

thanks for the info i'll read it over and decide how important the accuracy is. I may just use the GPS
Bill

 

[dklawson]

There is another, cheaper fix that will give you an accurate speedo, but it's only good in the daylight.

Do some google searching for Sigma BC800 bicycle speedometers. You'll find sites where these speedos are added to everything from golf carts to Lotus Super-7s. They are the bee's knees for easy to install, calibrate, and use add-on speedos. Their problem is that they lack a backlight. I have one on the dash of the Mini as my MPH speedo. The stock Smiths unit is in KPH and... like most Smiths speedos it's not terribly accurate and the needle bounces a bit. The Sigma is darn accurate and can be fine tuned to match your exact tire size. It's $25 well spent.