Calibrating Speedo

[woody]

I found a great website to help sort out you speedo if your changing clocks, engins or wheelsize.
The speedo drive in the gearbox consists of two parts ,a worm and a cog and by changing them you can change the ratio output to the speedo. On this page if you input your wheelsize, final drive and speedo tpm you can then try different ratios to get the closest match between speed and speedo reading.Ideally this could be done when the engine is out but I managed to do mine on an A+ box in the car although it did have a flip front. My speedo has gone from 15% to 2% accuritcy.
http://www.guess-works.com/Gearbox/Technical/ratio.htm

[whiskersdolmio]

Where abouts on the site is that info dude?!!

[macker]

i have a program at home in a zip file that can do that for you

[wzd345]

Can you open the zip??

[quote="macker"]i have a program at home in a zip file that can do that for you[/quote]

[keith]

i find the Co. Council very useful for this: they have helpfully put up a number of screens displaying your speed as you approach it.
A really useful one is on Clonkeen Road, which is a good straight stretch... so you can "calibrate" at a range of different speeds.
It has an annoying habit of showing in RED most of the time I approach it.

i haven't a clue what diff i have in, the engine number is missing, presumed lost, off the block. its an mg metro lump, with 12" wheels.

[The Marcos Graveyard]

Probably a 3.1 or 2.9 diff.

Sometimes there is a sticker on the back of the diff casing to tell you the ratio.

[woody]

Sorry I posted the wrong link, have edited in the right one.

[keith]

Sorry I posted the wrong link, have edited in the right one.

brilliant link!
http://www.guess-works.com/Gearbox/Technical/ratio.htm
turns out its 12H996AA which is MG Metro A+ with 3.44 diff.