Re: speed vs RPM-Spiders

[Jaap Bouma <j.h.bouma@xxxxxxxxxxxxx>]

>speed in mph = (rpm*60)*3.1417*(14/12 + 
>(20.5*2*0.6/2.54)/12)/5280)/4.5556/.079
>
>in words, speed in mph equals tach rpm times 60 minutes/hour times PI 
>times the rolling diameter ( which is 14inches divided by 12 plus 
>(205mmdivided by 10) times the aspect ratio divided by centimeters per 
>inch divided by inches per foot divided by feet per mile divided by the rear 
>end ratio divided by the transmission ratio.
>
>
>(try to say it fast without taking a breath.)

Makes one wonder why the rest of the world has gone metric, doesn't it?
Can't find anything wrong with the above though. But is it realistic to
assume the rolling diameter is not affected by compression of the tyre
where it meets the road surface?


Best, Jaap Bouma (Netherlands)
'87 GTV6 2.5 Grand Prix

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