Could some one please tell me the formula for calculating speed based on the RPM, gearing of the trans, and rear? I know tire size is a factor there too. I made a spreadsheet a few years ago to make the conversion based on each gear but I didnt actually write the formula down so now I need to change the rear ratio in the columns but I dont know what each value relates to anymore. I see there is a calculator on the main page but I want to put it back into the spreadsheet.
I found out the rear in my car isnt what I thought it was, throws my "speedometer" off a bit.

Thanks

 

never mind I found it in an old post I asked a long time ago

 

There is also a calculator on the main page.

 

Yeah I saw the calculator but it isnt what I wanted