The Unix Nerd's Domain

BMW Nerd's Gearing Calculator


This is a wee Javascript routine to help the really Sad and Nerdy amongst us who loose sleep worrying about gear and final drive ratios. Enjoy!

First you need to know your wheel diameter.

Width
in mm
Profile Alloy diameter
in inches
Total diameter
in mm

Then we can worry about the gearing. Default values are my 635CSi euro.

1st gear 2nd gear 3rd gear 4th gear 5th gear 6th gear Reverse Final drive
:1 :1 :1 :1 :1 :1 :1 :1
Gear
Engine speed RPM
Speed MPH mph
Speed Km/h km/h