# [Kartbuilding] Fwd: Kart Speed Short Version

Stephen Burke kartbuilding at gmail.com
Mon Oct 9 11:24:50 IST 2006

```Hi Dale,
I have put that article on my website. Thanks for your contribution to
the website. It was a tad long winded, but if karters are interested
enough, they will read it all.
If you would like to contribute anything else, feel free and I will
put it on my website. My time for for composing material myself is
limited.

P.S. To illeviate the problem of spam, I usually put my email address
into a picture without a hyperlink. That way bots cant detect that it
is an email and is a little easier for the average joe to cop on.
Best of Luck
-steve

On Mon, 6 Dec 2004 15:20:56 -0600, Dale Thomas wrote:
>
>
>
> Kart Speed Short Version
>
> How to Find Your
>
> Go Kart Speed Without Using a Speedometer
>
> (c) 2004 by Dale Thomas
>
>
>
> You can find your go kart speed without using a speedometer.  There are at
> least two ways to find the speed.  I'll call the ways Method 1 and Method 2.
>  Method 1 doesn't require a tachometer, but you will need a cheap
> calculator, a watch with a second hand and a known, accurately pre-measured
> distance (2 to 4 km or 1 to 2 miles) where you safely can ride your kart at
> full speed.  For Method 2 you'll need a cheap calculator, a measuring
> device, pen & paper and it requires using a tachometer.  Please keep safety
> in mind at all times for you, for passersby, for the property of others and
> for the kart.  Also, perform all measuring and counting steps with the
> engine completely stopped.
>
>
>
> There are some formulas to use, but they're pretty simple.   I'll show how
> to do the speed calculations for the metric and for the American measurement
> system.  Each step used will be introduced in a logical order and a
> description of each step will be given.  I'm giving a bare bones account of
> each method.  I have a detailed set of steps outlined in an article that
> runs 10 pages.  Some of the instructions are somewhat repetitive, but the
> article is aimed at teaching concepts rather than just as a presentation of
> a set of formulas to follow. Many of you will find the bare bones
> presentation enough of a description to get the job done.   If there are
> you from carhouse1nospanatall at hotmail.com.  If you copy and paste the email
> address you must delete the nospamatall part of the address.  If you do not
> delete that phrase I'll never get your email.
>
>
>
> Site" with permission from the author.  Anyone desiring to print the either
> of the articles mentioned for personal use, has the author's permission, as
> long as the copyright notice is included.  If anyone desires to use the
> author first through the address above.  Thank you very much.  Following are
> the steps to find your kart speed without using a speedometer.
>
>
>
> Method 1
>
>
>
> Method 1 requires you to ride your kart at full speed over an accurately
> pre-measured distance and to keep track of the exact amount of time it
> takes.  First instructions are for the metric system then immediately
> following are instructions for the American version.
>
>
>
> To find the KPH of your kart, say for example that you rode 4 km and it took
> exactly 8 minutes.  You need the distance in meters and the time in seconds.
>  That's 4000 meters and 480 seconds.  The formula is S=DTF where S is speed
> in kph, D is the distance in meters, T is time in seconds and F is 0.27778.
>  F is a conversion factor.  The factor was found by dividing 1000 meters by
> 3600, the number of seconds in an hour.  It means that one kilometer per
> hour is equal to 0.27778 of a meter per second.  Substituting in the formula
> we have 40004800.27778.    And the speed, S, is 29.999 KPH.
>
>
>
> To find the MPH of your kart, say for example that you rode 2-1/2 miles and
> it took 8 minutes.  You need the distance in feet and the time in seconds.
> Multiply 2-1/2 miles by 5280 and get 13,200 feet and then multiply 8 minutes
> by 60 seconds to get 480 seconds. The formula is S=DTF where S is speed in
> mph, D is the distance in feet, T is time in seconds and F is 1.46667.  The
> conversion factor is different this time because we're using the American
> measuring system.  It was found by dividing 5280 (the number of feet in a
> mile) by 3600, the number of seconds in an hour.  It means that one mph is
> equal to 1.46667 feet per second.  Substituting in the formula we have
> 132000  480  1.46667.  And, S, the speed is 18.75 mph.
>
>
>
> Method 2
>
>
>
> Method 2 takes a bit longer to calculate, is a bit more complicated,
> requires the use of a tachometer and needs information you will get directly
> from your kart.  Method 2 also uses more formulas but each one is about as
> simple and as easy as the one above.  The formulas will be worked in a
> logical sequence of steps.  We'll figure the mph first then afterwards we'll
> figure the kph.
>
>
>
> We are going to follow a very logical set of steps to find your kart speed
> consisting of finding the following: 1) the distance your drive wheel moves
> the kart while rotating only once, 2) how far the kart moves in a minute by
> multiplying the distance it moves in one revolution by the number if times
> the wheel rotates in each minute, and 3) the speed per hour by converting
> from the distance per minute.
>
>
>
> First get the information you need from your kart.  Before riding the kart
> and with the engine turned off, measure exactly, the outside diameter of
> your drive tire, and then count the number of sprocket teeth on the engine
> clutch and the number of teeth on the axle sprocket, making certain to count
> each sprocket tooth only once.  You also need to measure the maximum rpm of
> your engine while riding the kart at full speed over a level surface.
>
>
>
> Let's say for example that your drive tire measured 15 inched in diameter,
> that the engine clutch sprocket has 10 teeth, the axle sprocket has 60 teeth
> and that your maximum engine rpm while riding the kart is about 3000.
>
>
>
> Step 1 is finding the distance your drive tire moves the kart moves in only
> rotation.  The circumference of the drive tire is that distance.  The
> circumference is found with the following formula, where C is the drive tire
> circumference in feet,  is 3.1416 and D is the drive tire outside diameter.
> Substituting in the formula we have 3.1416  15 which gives C= 47.124 inches.
>  We'll need measurements in feet for this calculation, so change the
> circumference, found in inches, into feet by dividing the inches by 12.
> This gives the drive tire circumference, and the distance the kart will move
> with only one drive tire rotation equals 3.927 feet.
>
>
>
> Step 2 is finding the distance the drive tire moves the kart in one minute.
> Let's call this distance Tk in our formula.  Step 2 is the most complicated
> because we must work out a few sub steps first.  To find Tk we need to know
> the distance of one drive tire rotation (C from above is 3.927 ft) and how
> many times the drive tire revolves each minute.  To get the drive tire rpm
> (let's call that RPMw) we need to use the other information we got from the
> kart.  First we need to know the maximum engine rpm (let's call that RPMe)
> that we read on the tachometer while riding the kart.  And let's assume for
> the sake of this example that the tachometer reading was about 3000.  The
> drive tire doesn't turn as many revolutions per minute as the engine because
> of the drive system.  That is, the number of teeth on the engine clutch
> sprocket and the number of teeth on the axle sprocket, isn't the same.  The
> relative difference between the number of teeth on these two sprockets is
> called the ratio.  For our formula let's use the symbol, R, to designate
> ratio.  The formula we'll use to find the ratio is  where R is ratio, Ta is
> the number of teeth on the axle sprocket and Te is the number of teeth on
> the engine clutch sprocket.  We get the ratio (R) of the drive system by
> dividing the number of axle sprocket teeth by the number of teeth on the
> engine's clutch sprocket.  Then after we know the ratio we can find the RPMw
> by dividing the maximum engine rpm (RPMe) by the ratio.  We get RPMw by
> using the following formula.
>
>
>
> So, now that we know the formulas to use and the steps to use, so lets
> substitute the information we got from the kart to find how far the drive
> wheel moves the kart in one minute.  .  For this formula we know C, but we
> don't know RPMw yet. .  For this formula we know RPMe, but we don't know R,
> the ratio of the drive system yet.  , is the formula for ratio.  We can work
> this formula because we counted 60 axle teeth and 10 engine clutch teeth, so
> let's substitute that information to find the ratio.  We have 60 axle teeth
> divided by 10 engine clutch teeth and the result is that R is equal to 6.
> Now that we know the ratio we can find RPMw.  , substituting, we have 3000
> maximum engine rpm divided by 6 which is equal to 500 drive wheel rotations.
>  Finally, we can find the distance the drive wheel moves the kart in one
> minute with the formula.  Tk is the distance the drive wheel moves the kart
> in one minute, RPMw is the number of times the drive wheel revolves in one
> minute and C is the distance the drive wheel moves the kart in one
> revolution.  Substituting, we have 500 times 3.927 feet which gives Tk
> equals 1963.5 ft. per minute of kart travel.
>
>
>
> The last formula we need is one to change feet per minute into miles per
> hour.  If we divide the number of feet per minute (1963.5) by the number of
> feet in a mile (5380) we will know the portion of a mile that the kart
> travels in one minute.  Then if we multiply the number of minutes in an hour
> we'll find how far the kart will travel in an hour.  So, is one formula we
> can use.  Substituting, we have 1963.5 divided by 5280 feet, which equals
> 0.371875 of a mile in one minute.  That multiplied by the 60 minutes in an
> hour is equal to 22.3125 MPH.
>
>
>
> The MPH formula can be stated in at least two more ways and still give the
> correct results.  Notice the parenthesis, which tell the one solving the
> equation to do the operation inside the parenthesis first.  The formula can
> be stated   and, honoring the parenthesis, the answer will be the same.  The
> formula can be condensed even further to.  The answer will still be correct.
>  If I worked the formula as stated at the last, I might have gotten the
> correct answer, but I might not have understood why the formula worked.
>
>
>
> KPH
>
>
>
> The kph section will be shorter because it is a bit simpler and you have
>
>
>
> First count the sprocket teeth, measure the drive tyre outside diameter and
> measure the maximum engine rpm while riding at full speed, as mentioned
> above.  Also, please observe all safety precautions noted in the first
> paragraph.  For the figures we'll use the same kart used in the previous
> example.
>
>
>
> Step 1, the same 15 inch diameter drive tyre measures 381mm in the metric
> system.  The formula used to find the distance the drive tyre moves the kart
> in one rotation is.  Substituting, we have 3.1416 multiplied by 381 gives C
> equal to 1196.9496 Mm.  We need figures stated in Km.  You can work the
> conversion at any location that gives Mm by dividing Mm by 1000000 because
> there are 1000000 Mm in each Km.  So, 1196.9496 divided by 1000000 equals
> 0.0011969 Km.  So, C equals 0.0011969 Km
>
>
>
> Step 2, already we know the sub steps to be performed from the previous
> explanation of mph.  We want to know the distance the kart will be moved by
> the drive tyre in one minute (Tk) and we know that we must find RPMw and R,
> and we know that to get the RPMw we must find the ratio first.  We're using
> the same kart in this example with the same number of teeth on the engine
> and drive axle.  So, the formula for ratio is,   and substituting, 60  10
> gives R equals 6.  , substituting, the engine rpm 3000 divided by 6 gives
> RPMw equals 500.  Finally, we get the distance the drive wheel moves the
> kart in one minute by the formula.  Substituting, we get 500 times C
> (0.0011969 Km.) gives Tk equals 0.59845 Km per minute.
>
>
>
> Step 3 is the easiest.  The formula for kph is.Since we already calculated
> the distances in Km, Tk is expressed in Km here, so, we again substitute,
> and 0.59845 Km per minute multiplied by 60 minutes in an hour gives KPH
> equals 35.907 kph.
>
>
>
> The drive system referred to this point has been the chain drive type.
> There are two other systems that are common.  One is a belt drive system
> characterized by its having a belt only, which is driven by a pulley on the
> engine (Pe) and a pulley on the axle (Pa).  The ratio for this system is
> found by, that is, dividing the measurement of the axle pulley by the
> measurement of the engine pulley.  The measurement of both pulleys must be
> the radius, the diameter or the circumference, not one measurement made of
> the diameter and the other measurement made of the circumference.  If it is
> more convenient to make measurements of pulley in diameter and the other in
> circumference one measurement must be converted to match the designation of
> the other.
>
>
>
> Another type of drive system is the torque converter.  This system is a
> combination of belt and chain drive.  In research for this article I found
> that two torque converters were common and that the ratio for each was
> published.  One converter, called Torque-A-Verter 2 has a ratio of about 5,
> and the Comet brand has a ratio of about 3.  The 10 page version of this
> drive systems.
>
>
>
> Also, in the 10 page version is information and formulas to use a
> combination of Method 1 and Method 2 to find your engine maximum rpm if you
>
>
>
>
>
>
> Happy karting,
>
> Dale Thomas
> Remember to remove the phrase nospamatall from the email address or I won't