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Re: Re: calculated speed

To: Dan Dwelley <maine2me@yahoo.com>
Subject: Re: Re: calculated speed
Date: Tue, 13 Jun 2000 15:05:52 -0400
Cc: spridgets@autox.team.net
Ah....  A child of the eighties.  I bet less than 1 in 1000 kids younger than 
18 can identify that line......  In ten years,   1 in 1000 younger than 18 will 
be able to identify the _biggest_ actor in the movie.  Folks,  I'm getting 
old.....

Michael
'78 Midget (I'm sorry,  did you want me to move on my own power?)


Dan Dwelley <maine2me@yahoo.com> wrote:
> "Lighten up Francis!" Sounds like someone needs a hug!
:o))

I was just being Facetious!

Damn!

Dan Dwelley
 
--- John Holliday  wrote:
> If we are going to continue this anal discussion,
> the
> rolling circumference of the tire with the car's
> weight applied is different than the circumference
> measured on your spare tire off of the car. 
> 
> Better still just top end your car's speed thru your
> local community's speed trap. Email us a copy of the
> citation and we will all know who's is fastest.
> 
> John Holliday
> 
> 
> --- Dan Dwelley  wrote:
> > > Mark a spot on one rear tire and roll the car so
> > the
> > > mark touches the
> > > pavement. Mark the pavement at this point.  Roll
> > the
> > > car forward with you in
> > > it (for highest accuracy) until the mark on the
> > tire
> > > is again on the ground.
> > > Mark this spot and measure between them.  This
> is
> > > the distance the car moves
> > > forward for each rotation of the axle, call it
> > "C".
> > > 
> > 
> > "C" for Circumference? I've got a better
> idea...just
> > measure the circumference of your spare tire (if
> > it's
> > the same size as you have on your car). I bet
> you'll
> > get the same measurement with less effort! :o)
> > 
> > Dan Dwelley
> > no wiz but I can determine the circumference of a
> > circle and apply it to linear measurement. :o)))
> > 
> > 
> > --- Glen Byrns  wrote:
> > > Here's how I figured my theoretical speed at
> > various
> > > rpm's:
> > > 
> > > Mark a spot on one rear tire and roll the car so
> > the
> > > mark touches the
> > > pavement. Mark the pavement at this point.  Roll
> > the
> > > car forward with you in
> > > it (for highest accuracy) until the mark on the
> > tire
> > > is again on the ground.
> > > Mark this spot and measure between them.  This
> is
> > > the distance the car moves
> > > forward for each rotation of the axle, call it
> > "C".
> > > In my case, C=69 5/8" =
> > > 69.625".
> > > 
> > > With a 4.2 rear end, the drive shaft will turn
> 4.2
> > > times to turn the rear
> > > axle one revolution.  Assuming a fourth gear
> ratio
> > > of 1:1, then at 6K rpm,
> > > 6000/4.2 = turns of rear tire per minute =
> > 1428.72. 
> > > Multiply by 60 to get
> > > turns per hour, = 60 x 1428.720 = 85732.2
> > > This number times the number of inches forward
> for
> > > each turn you figured out
> > > earlier(C)tells you how many inches forward for
> > each
> > > hour at 6k rpm in
> > > fourth. Divide by the number of inches in a
> > > mile(63360) and you should get
> > > miles per hour.
> > > 
> > > {(rpm/rear end ratio)x 60 x C }/ 63360
> > > 
> > > So for a 4.2 rear end, 69.625 inches per turn of
> > > tire, fourth gear:
> > > (6000/4.2) x 60 x 69.625 / 63360 = 94.18 mph, 
> at
> > 5k
> > > rpm = 78.49mph
> > > 
> > > 
> > > I'm sure someone with a better memory of math
> will
> > > correct me, but luckily I
> > > play with DNA for a living and don't do gobs of
> > > math.
> > > 
> > > 
> > > 
> > > > I havn't seen anybody talk about tire size
> which
> > > can have a very difinite 
> > > >effect on speedo error and correct top speed. 
> > Look
> > > at any tire chart and 
> > > >you will see a big difference in tire
> > circumference
> > > with the tires sizes 
> > > >very close together if not the same size. 
> Don't
> > > forget to take this into 
> > > >consideration.  Does anyone one out there have
> > the
> > > formula for determining 
> > > >top speed using tire circumference, axel
> ratios,
> > > and rpm's?
> > > >
> > > >
> > > >BOB
> > > >65 Midget vintage racer
> > >
> >
>
>________________________________________________________________________
> > > >
> > > >
> > > Regards,
> > > Glen Byrns
> > > '59 Bugeye
> > > 
> > 
> > 
> > =====
> > Dan Dwelley
> > 77 Midget
> > Alexandria, Va.
> > 
> > __________________________________________________
> > Yahoo! Photos -- now, 100 FREE prints!
> > http://photos.yahoo.com
> 
> 
> __________________________________________________
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=====
Dan Dwelley
77 Midget
Alexandria, Va.

__________________________________________________
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