getting close to my go kart build, need some electrical help :)

[garyegt]

hi there folks, me again! ok its getting very close to my build for college and i am just looking for some help with regards power etc.

first off i was looking at this kit:

24v 900w 11 tooth sprocket motor, controller and throttle

with that i would have a 90 tooth sprocket, giving me a ratio of 8.18:1

and also a set of wheels like this

ok im not the skinniest person in the world so what i need to know is will that be enough to move me (say 18 stone) plus the kart itself.

if not has anyone any reccomendations?

btw all it has to do is move, it doesnt exactly have to be fast, but a bit of speed would be nice

 

[Bluethunder3320]

ill tell you it wont be fast with that motor. id go with a 36v 1000watt setup. with that it might go 15 or 20.

but the 24v might be somewhere in the range of 5-12. i know you just want it to move but if it is crawling you might not want that either.

if i was you id get a old go kart off craigslist (without motor) and use the steering components, brakes, cables, axles, spindles, seat, tires, and then you can slice up the frame for metal.

i got a go kart with a non running 6.5 tecumseh and spare tires for $50 US, which is near what those tires cost alone.

 

[redsox985]

Are there any go kart tracks near you? Not the rental type, but like competition style places. Often times, racers will use their tires a few times then sell them because they get new ones every few races, not because they are old and beat up. If you go and ask around, even just asking for where to get tires or if they have some to sell, you will turn up some good prices.

 

[newrider3]

A 90 tooth sprocket, if #35 pitch, would be nearly twice as big as those rear tires. I'm not sure how big it will be in #25 pitch, but it is still quite large.

 

[r97]

the pitch dia of a 90t 3/8" pitch sprocket would be 10.75" dia, so about 11.25" actual dia, so depending on the dia of the tires purchased, it would clear on flat ground, then bottom out on a stick, lol, but not 2x the dia (those tires are usually 10-12" in dia)
your motor is 1.2hp, if you find the rpm i can find its torque and that can help us with gearing.

 

[redsox985]

Time for a jack shaft. How do you calculate the OD of a sprocket going by teeth and pitch?

 

[r97]

i guess ill give you the full explanation. the pitch as we all know is the distance between the centers of the two roller pins next to each other on a roller chain. lets say we wan't to find the pitch dia of a 60t #40 sprocket, we know the pitch is 1/2" or .5", and that we have 60t going around the outer edge of the sprocket, so if we multiply 60t*.5" we get 30 inches, that would be the pitch circumference(not sure if there is actually such thing as pitch circumference, but lets go with that), and as we all know dia*pie= circumference, so circumference/pie=dia. 30"/3.14159265= 9.5492966 or appropriately a bit over 9 1/2" inches in pitch dia. now the actual dia is different than the pitch dia because the roller pins all sit further into the sprocket than the tip of each tooth, so you would need add that to your answer to find the actual dia. so, you can either do this calculation (pitch*teeth/pie=pitch dia) or go to any one of these or other websites,
http://www.compgoparts.com/TechnicalResources/JackshaftRatioCalculator.asp
http://gokartguru.com/engineering_tool_kit.php
this is also very help full,
http://www.gizmology.net/

 

[redsox985]

Oh, that's pretty simple.

 

[r97]

yup, lol