Top Speed Calculator

it has links for some quads where the transmission ratios are already there and it will get your MPH in each gear
http://home.earthlink.net/~gellett/mph.htm

Thats neat... It accurate?

it is 100% accurate.
well the tires might expand some
but if you know the max RPM your engine can turn, and the tie diameter (again every tire will not be the same diameter even if they say 20") it will get you the speed at that rpm.

So how do you do this? Just type in numbers? Or you really have.to drive it.

do what?

you should know your tire size.
for max RPM you really just guess. like i know mine will hit over 10K but power drops around 9500.

you might have to search for your primary reduction ratio and gear ratio.
secondary gear ratio or final gear ratio is the sprockets.

Ok i see lol

im confused i dont think there is anyway this can be accurate, unless im misreading the info its giving us it doesnt calculate for port work, carbs, pipes or rider weight

ya, that stuff doesn't matter.

it takes the RPM your engine is spin, then it calculates the RPMS the power tires are spinning by using very simple math. it then takes the circumference of your tires and takes the RPM the tire is spinning and times that to the circumference. it takes that number which will be in inches/min and converts that to MPH.

very simple.
it really isn't top speed, but what your speed should be at that given RPM.

their is some problems since no two tire companies have the same diameter for their 20" tire, and some tires will swell up at spins and grow and it doesn't take this into account.