I have recently replaced my diff with a 3.1 to lower my highway rpms which in turn has made my speedo read incorrectly (well even worse than before), as Xmas is just around the corner I know that jolly fat guy in the red suit is bringing some new bits for my mini one of which being http://www.minispares.com/product/Classic/Gauges/Speedo/13H4444MGKIT.aspx?1404&ReturnUrl=/shop/classic/Gauges.aspx|Back%20to%20shop

How do I go about changing the setup so that my new speedo will read close to correct with the 3.1 diff?

cheers,

CJ

First of all you need to know what 'Turns Per Kilometer' your speedo is! It's on your speedo front facier.

http://www.guess-works.com/Tech/speedo.htm

Check out the link to see where on your speedo it's located.

Now check out this link:

http://www.guess-works.com/Tech/ratio.htm

When you have entered all the data it will tell you your recommended speedo drive combination for your given speedo!

Cheers Shane

_________________
If it's not a Cooper S, the mini was designed to be modified!

Be aware that the speedo and the odometer are two separate instruments. The speedo can be adjusted (basically by varying the distance between the two large shiny discs behind the face) - of course in practice its more difficult than that. If you have a local instrument shop its not too expensive.

The odometer however is mechanically driven and requires either the correct drive gears (attached to the rad end of the gearbox) or a separate little gearbox that goes in series with the speedo cable.

Or you just calibrate your tacho using GPS and ignore the speedo....

Or, just do the math. The difference between a 3.1 and a 3.76 is almost exactly 20%. So, if your speedo/odo used to tell the truth, now you just add 20% to get the new truth...

Cheers, Ian

Nice, i will have a look at the new speedo when it gets here an see what ratio it needs. Who knows I may be able to get both the speed and odometer to read close to correct