[WARNING: DELETE NOW IF YOU DON'T CARE ABOUT TIRE SIZES AND SPEEDO
READINGS, ETC.!!!]
On Thu, 16 Mar 2000, Carter Shore wrote:
> This was an issue because of a speeding ticket I got,
> had to go get a certificate of calibration from a
> Licenced Speedo shop, take it before the judge.
Been there, almost did that. Would've, except:
a. Speedo was inoperative at the time of the ticket, and I informed the
ever-so-nice peace officer of that fact. Perhaps not the smartest thing to
do.
b. I went to Traffic Court almost HOPING to be able to stand before the
judge and talk about x number of mph for every 1000 rpm of the tachometer,
which I was religiously monitoring, etc., yadda, yadda, blah, blah....But
before that could happen, all of us heinous speed demons were ushered into
a room full of State Troopers (the ones who caught all of us) for what
could best be described as a one-on-one gang plea bargain session. "Ya
look like a nice young man (ha) Mr. Mace, and your record is good (da*n
straight it is). How 'bout we just settle for -- instead of 72 in a 55
zone -- a reduced charge of 'speed unreasonable and prudent (and allow
this fine township only seventy of your hard-earned dollars to pay for
their next junket)?" [No, I'm not at all cynical about the process.]
c. I think the tach is a bit pessimistic (yes, I know I'm using that word
correctly this time. Hi, Jeff. :-) ) in the car I was driving ('72 Mk.IV).
> FWIW, using the formula, gets 18 MPH/1000 RPM with
> 4:11 rear and 25" dia tires. So it depends on the size
> of your thumb.
I'm really NOT trying to pick a fight, Carter, but I think your thumb
stayed too long on one of the keys of the calculator. ;-) Seriously, I
have no problem with the math, only the figures you input. Doing some
quick scanning of some tire company web sites, I find that tires in the
25" diameter range are sizes such as P195/70R14, or maybe a 185[80]R13 or
105/70R13, or maybe even the 165SR15 -- all far too big (tall) a tire for
any Spitfire (IMHO). The diameter we'd be looking at for the average
Spitfire is more like 22.5-23.5". [Numbers based in part on info from
Dunlop -- specifically SP40 and SP20 Metric tires.]
> So I used the 'conservative' number (20) thereafter,
> because it meant that at indicated 2,000 RPM, I was
> actually a bit below the 40 MPH speed limit....
If you look at it that way, you should have been fine; 2000rpm would
equate to about 32-24 mph unless you've got some of those really big tires
I mentioned above.
> This makes a difference if you live in 'revenue
> hungry' or 'zero tolerance' jurisdictions.
See above. ;-)
--Andy
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Andrew Mace e-mail: amace@unix2.nysed.gov *
* *
* Mrs Irrelevant: Oh, is it a jet? *
* Man: Well, no ... It's not so much of a jet, it's more your, er, *
* Triumph Herald engine with wings. *
* -- Cut-price Airlines Sketch, Monty Python's Flying Circus (22) *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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