I've got a program for that let me work it out.

You are doing both yourself & all of us proud. Good bloody fortune to you for the future.
Sorry i don't have a formula, but it would give you a speed that is probably a whisker short of the true speed, as it would not take onto account tyre growth at that speed. Hey, that's gotta be worth a couple of extra K's

Hi guys does anybody know how to work out your speed from revs gearing and tyre size?? I know there is a formula.
Today at bathurst down conrod I pulled 7800 in fith 0.83:1 overdrive with 4.625:1 diff and 225/50/15 tyres. Wondering what sort of speed that equates too. I estimate around 215-220
The only reason I know what revs I was doing is it hit the rev limit on two of my runs.
The datto did me proud run strong all day blew and intercooler pipe on one run best time of 49.0 over one second ahead of second place outright in a late model big $$$ porsche.
here is a picture from today
1200 bathurst