Sprocket Question

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DDeJAegher

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The sprocket on my kart's axle is #60 pitch and has 35 teeth. At princess auto, there are some 30 tooth in #60. What affect would this have on my speed/power
 

itsid

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14% more speed and 14% less torque.

(maybe the lack of torque will prevent reaching top speed already.. we can't tell with just that one number)

Anyways.. you sure it's #60 with 35 Teeth?
that's a huge chain ...(3/4" roller distance)
#35 chain with 60 T is what most of us have (at least somewhere in the shed ;))

'sid
 

DDeJAegher

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Yep, it's for sure #60. Its a big kart so, I will want more torque so I can reach my top speed. I'm panning on putting 20-22" high tires on the back. Would that sprocket be suitable?
 

itsid

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Okay, just asking..

Well it's hard to judge what will work and what not with the little details you're giving away ;)

So..
how much does the kart weigh (with you in it)
what engine will be used (HP, rpm etc)
what's the transmission set up? (Torque converter, jackshaft etc..)

Also post pics!

'sid
 

DDeJAegher

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Okay, I'm not sure how much it weighs with me in it, but I am about 170lbs and I'm going to guess the kart is is pretty close to 300 lbs. The engine is painted over but, I can tell it's an old Kohler auger motor. 12-15hp. The transmission is a homemade one. There is a pulley on the motor and a loose belt connects it to a secondary clutch (I think that's what it is called [the one with the spring]) And there is a petal that pushes another pulley onto the belt thus, tightening it. I will post a few pictures once I get back from Fishing.
 

itsid

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so roughly 470-500 lbs (let's take 500 to be on the safe side)
let's just assume you have 12Hp (if it's more no harm is done ;))

now what's the pulley diameters (both pulleys).. what's the sprocket toothcounts (both sprockets)?
So we can find the overall gear ratio.

Oh, and 500lbs doesn't require a #60 chain.. a #40 will do ;)
Anyways.. just saying :D

'sid
 

DDeJAegher

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But, the #60 will work. Right? All I need is to either remove the sprocket from the old axle or buy a new one with a bit more or less teeth. That way, I'll be on the road much faster.
 

mrbee7

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The TAV 30 torque converter on my cart has 9 teeth- the sprocket on the axle has 60 teeth- how do I figure out the chain size?
 

OzFab

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The TAV 30 torque converter on my cart has 9 teeth- the sprocket on the axle has 60 teeth- how do I figure out the chain size?

That would've been better placed in your own thread; although it may be relevant to the subject, that's what we call hijacking a thread... just so you know...
 

itsid

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Well of course a #60 chain will work.. it's just a bit overkill :D

Again, without knowing the overall gear ratio it's nearly impossible to tell if you can or cannot swap to a 30T sprocket.

So again: the pulley diameters and the other sprocket size is needed to make a judgement.

let's just assume the following:

say your first pulley (engine side) is 3", the second is 4" and directly connected to that is a 10T sprocket.
your gear ratio is already 4.67:1 which is already bad for your weight and hp
reducing it further with a 30T sprocket will make it 4:1
and that's nearly impossible for your belt to manage without slipping (wearing, then failing).

Now let's assume your first pulley is 4" and the second is 7"
then 10 and 35 teeth sprockets
Your current gear ratio is 6.13:1 wich is good (especially if you have large wheels)
taking 5 teeth will reduce it to 5.25:1 which is maybe still good enough with the engine you have.

So swapping a 35T sprocket with a 30T sprocket could work, but it can also fail very miserably;
without all the details we cannot tell :(

'sid
 

DDeJAegher

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The diameter of the pulley on the motor is 4.5" and the second is 10" What would the best amount of teeth be? The old one had 35.
And my dad and I started the motor today, just needed a new plug and it runs great.
 

DDeJAegher

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Here are the facts:
Weight 450-500 lbs
Tire dia 20-22"
Horsepower 12-15
Engine pully dia 4.5"
Second pully dia 10"
Jackshaft sprocket 12 teeth
Axle sprocket undetermined

What else am I missing?
 

itsid

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Ah.. current gear ratio (35T axle sprocket)
6.48:1 (okay for 22" wheels and 13 HP)

target sprocket (30T)
5.56:1 (okay for 18" wheels and 15HP)

wheels should not be bigger nor engine smaller than the numbers in brackets and you should be okay.
Since your primary reduction is a belt you still can encounter a lousy performance due to a slipping belt,
so I wouldn't place any bet on that setup (not even if you have 18" wheels and a 15Hp engine)
...just sayin' ;)

'sid
 

itsid

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Again, with just 12HP and 22" wheels it will NOT work
(the first slight inclination and it will fail)

with 15HP and much smaller wheels it SHOULD work
(due to the belt drive it all depends on the quality of the transmission)

'sid
 
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