Math question

Oct 24, 2003 7 Replies
L

Ok here it goes, knowing your tire size, your engine rpm, your trans drive gear, and your final rear end drive gear, how do you throw those together to get your final potential speed?



I tried rpm/trans gear/drive gear*tire size in inches/the number of inches in a mile* 60(the number of minutes in an hour since its rpM). What am I doing wrong, or not seeing right?



I found calculators on the internet for it which work great, but I want to be able to do the math myself, without having to run for a computer. $5.00 Solar crappy calulator, maybe.



Brian


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T

what website did you use? I don't know the formula, but maybe we can jack it from the JS in their pages :-)

Travis

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B

I can send you a Excel spread sheet and you can steal it from there.

Al

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M

it s RPM= MPH x GR x FTR x 336 / TD

RPM = well RPM MPH = well MPH you want to see the rpm at GR = gear ratio FTR = final trans ratio if you are going to using overdrive

336 = magic number for it to work out right TD = tire diamter

moderator at

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F

MPH=Tire Radius/168 * RPM/Gear Ratio RPM=168 * Gear Ratio * MPH/Tire Radius Gear Ratio= Tire Radius * RPM/168/MPH Tire Radius=168 * MPH * Gear Ratio/RPM

Bird79

1979 Firebird Esprit 1973 455 YC
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L

Dang, thanks for all the replys. :)

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B

Make sure the tyre size is the tyre's circumfence and NOT its diameter or radius. If you use a radius, you will need an additional 2 * PI in there.

ALSO: tyres slip at high speed. And I believe that they slip a lot. Over 10% I believe.

Bram

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F

Now let me get this straight, you measure the outside diameter of your tire, then multiply by the girth of your girlfriend's ass, minus her squat height, then figure-in her heffer donut needs for a month, and finally add how big her gut is after she japped you with 2 or 3 brat kids-- and that gives you the size of your blue balls at this point, right?

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