calculating mph from tire circumference?

[entropy]

Sumner,
The "slip" adjustment is not critical at all, we just want to go to WOS with appropriate alternative gearing in case our current 2.19 proves to long to achieve 175-200 at the Q.  I am not trying to "mic a brick", just looking for directional info which has been generously provided by all you guys.   My big AH-HA was tq converor slip; you and Tom both pointed in that direction last night.
 

As far as crossing the Q at the speed needed for each license we plan to use the GPS display on the dash. 
If that is too hard to see, i'll set up a warning light triggered by the GPS speed.  Racepak warning lights are impossible to miss, even for me.
Karl

[entropy]

I have, and still do, used Karls corrected spreadsheet for years and it is spot on!!

[Stainless1]

Karl, looks like your alternative 256 gear would still have you above 175 at 5800... if you have an alternative gear set I would bring them...
As a thought, 26 in tall tires would give you a 244 gear, and probably be easier to change unless you have a quick change.
When we change to a class that we need to long course qualify in, we always initially gear for the quarter number. 
Of course you may be over worrying, I suspect you will both be able to A license at the meet 

[entropy]

Karl, looks like your alternative 256 gear would still have you above 175 at 5800... if you have an alternative gear set I would bring them...
As a thought, 26 in tall tires would give you a 244 gear, and probably be easier to change unless you have a quick change.
When we change to a class that we need to long course qualify in, we always initially gear for the quarter number. 
Of course you may be over worrying, I suspect you will both be able to A license at the meet 

Stainless,
we do have a Winters quick change
(But we do hope we don't need to get into it  )
Karl

[fredvance]

Is it harder than changing gears on a Busa??

[entropy]

"I'd rather be lucky than smart" = karl's slogan

After plenty of discussion, TFA went to the recent WOS using a 6.0% "slippage" factor to predict mph & select gearing.
I determined that factor at 2012 WOS for my bike.

2.19 overall gearing, 6% "slip"  @ 91.25" tire  @ 5722rpm = 212.2mph predicted

results please...drum roll...                                 5722rpm  = 209.6mph measured(GPS) = 7.2% "slip"

pure luck that the prediction turned out to be so close, i wasn't thinking at all about our car's tq convertor...

[WOODY@DDLLC]

The difference is obviously entropy! 

[entropy]

The difference is obviously entropy! 

LOLOLOLOLOLOLOLOLOLOL