Speedo error using different ratio diffs?

[m3matty]

Hi chaps

I'm about to swap the 3:91 diff on my 325i touring for a 3:64 diff.

How much speedo error will that give me??

Any ideas?

Matt

[Davenotouring]

If the new diff comes with the speedo sender still plugged in, then you can plug into that and it should be fine.



Otherwise it could be more than 7% out.

[Karan]

there should be no differnence at all.... as the sensor is attached to the crown wheel part of the diff and parts that go to the oiutput shaft so there would be no difference at all

just plug ure new diff in and away u go