Hi to all, first time on the forum ... I'm building, trying to build, a kart for my grand kids. I've got a 6.5 hp motor and the kart has 15" tires (they're 15" tall) What I need help with is how many teeth should I have on the centrifugal clutch and how many on the rear axil sproket... I've looked at different sites but it makes no sense to me .. any help is appreciated. Thanks, Curly
sproket size .. help
- Thread starter Curly
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Doc Sprocket
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Welcome to the forum.
We need more info. Size and weight of the kart (pics would be dynamite), expected riding terrain, and planned top speed.
How old are the munchkins?
We need more info. Size and weight of the kart (pics would be dynamite), expected riding terrain, and planned top speed.
How old are the munchkins?
Good morning, the kart probably weighs around 100/125 lbs, kids are 5,6,@8. No ruff terrain, gravel driveway, front yard, street. Don't need for them to go real fast to start with, this is our first kart. Maybe when they get used to it I could change the rear
sproket ?? Got'a keep Gma happy, for awhile anyway ... can't do pic's, sorry.
sproket ?? Got'a keep Gma happy, for awhile anyway ... can't do pic's, sorry.
With tyres 15" tall, you are going to have to gear quite low. I would suggest at least 8:1 or 9:1. If you have a 10T clutch, this will mean that you will need a 90T axle sprocket if you are wanting to go direct from clutch to axle. A 90T sprocket is just over 10" according to the Azuza catalogue below.
Azusa #35,#40 and 520sprocket diameters
http://www.azusaeng.com/Sprockets/AzSDno35.pdf
http://www.azusaeng.com/Sprockets/AzSDno40.pdf
http://www.azusaeng.com/Sprockets/AzSDno50.pdf
You might want to go for a jackshaft (JS) if you feel direct drive is not practical. A jackshaft is used for compound gear reduction using smaller sprockets than what you could with direct drive. The jackshaft itself uses 2 sprockets, one on each end. You can use several sprocket size combinations to get the same gear ratio. For example, to get a 9:1 gear ratio, you could use a 10T clutch, going to a JS IN sprocket of say 25T, a JS out sprocket of 12T and a axle sprocket of 45T. The calculation goes something like this:
(JS IN/clutch)*(axle/JS OUT)
= (25/10)*(45/12)
= 2.5*3.75
= 9.375:1
You get the idea....
Azusa #35,#40 and 520sprocket diameters
http://www.azusaeng.com/Sprockets/AzSDno35.pdf
http://www.azusaeng.com/Sprockets/AzSDno40.pdf
http://www.azusaeng.com/Sprockets/AzSDno50.pdf
You might want to go for a jackshaft (JS) if you feel direct drive is not practical. A jackshaft is used for compound gear reduction using smaller sprockets than what you could with direct drive. The jackshaft itself uses 2 sprockets, one on each end. You can use several sprocket size combinations to get the same gear ratio. For example, to get a 9:1 gear ratio, you could use a 10T clutch, going to a JS IN sprocket of say 25T, a JS out sprocket of 12T and a axle sprocket of 45T. The calculation goes something like this:
(JS IN/clutch)*(axle/JS OUT)
= (25/10)*(45/12)
= 2.5*3.75
= 9.375:1
You get the idea....
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