briggs driver
New member
Title pretty much explains it. I have a 10 tooth clutch and need to choose a drive sprocket size.
Go kart gear ratio with briggs 5hp with 9.5in tall tires
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mckutzy
Well-known member
60t, try that and go from there...
Nosandwich
The REAL Poboy
If they are indeed 9.5" tall from ground to top, you could go much lower, 54 tooth or smaller, what are your expectations for this kart?
60 should be fine
briggs driver
New member
60 wont work. the chain wont clear. need to choose a smaller one.
Texan
Senor Member
How about a 54?
briggs driver
New member
think im gonna do that. would it start on a hill fine with a centrifugal clutch? the kart is 75-100lbs and im 125.
Tpdingo
Member
If you are trying to hill climb on a clutch, you shouldn't be using a clutch.
Texan
Senor Member
Not sure. I have a 54 on one kart and it pulls me around, but my setup has a jackshaft and runs on a belt drive centrifugal clutch.
And I say with me and the kart its easily 300lbs.
So for your total weight at 200lbs, i say it should do ok.
Probably depends on terrain and grade of the hills.
And I say with me and the kart its easily 300lbs.
So for your total weight at 200lbs, i say it should do ok.
Probably depends on terrain and grade of the hills.
mckutzy
Well-known member
Lets see some pics of said machine, Engine ect???
Nosandwich
The REAL Poboy
Why not? As long as it's not super steep, and it's not from a dead start, but a rolling one, I don't see the problem.
And with a 10 tooth clutch, I didn't expect a #35 chain, so, part of what I was thinking with such small tires a 60 tooth 40/420 may be too big.
well a ten tooth clutch will be #40 chain.. a #40 sprocket with 60 teeth has a diameter of 9.8"
So that's a no for 9.5" wheels
which leads me to the question.. where you got those tiny wheels in the first place..
smallest kart wheels I'm aware of are 10" on the front and 11" on the back (a handfull of exceptions going down to 10.5" on the rear axle)
9.5... makes me baffle (or fear inappropiate wheels
)
Now, yes 54 teeth #40 is 8.8" which only gives you .25" of clearance roughly
still NOT ENOUGH!
(one bump and your chain knows a story to tell about 'groundforce')
and gearing even higher (smaller number) means you'll likely run into other troubles along the way.
(lack of torque, burnin clutches like crazy etc.pp.)
Soooo..
11" wheels or compound gearing (i.e. buy a jackshaft gear it 3:1 on one and 2:1 on the other side... axle sprocket 20-30 teeth is nicely providing you clearance and the 6:1 overall ratio keeps your kart moving without destroying a clutch)
Or buy a Torque converter instead, gear 4.8: and hope for the best.
(sticking with #40 chain and a ten tooth tc-sprocket..)
'sid
So that's a no for 9.5" wheels
which leads me to the question.. where you got those tiny wheels in the first place..
smallest kart wheels I'm aware of are 10" on the front and 11" on the back (a handfull of exceptions going down to 10.5" on the rear axle)
9.5... makes me baffle (or fear inappropiate wheels
)Now, yes 54 teeth #40 is 8.8" which only gives you .25" of clearance roughly
still NOT ENOUGH!
(one bump and your chain knows a story to tell about 'groundforce'
)and gearing even higher (smaller number) means you'll likely run into other troubles along the way.
(lack of torque, burnin clutches like crazy etc.pp.)
Soooo..
11" wheels or compound gearing (i.e. buy a jackshaft gear it 3:1 on one and 2:1 on the other side... axle sprocket 20-30 teeth is nicely providing you clearance and the 6:1 overall ratio keeps your kart moving without destroying a clutch)
Or buy a Torque converter instead, gear 4.8: and hope for the best.
(sticking with #40 chain and a ten tooth tc-sprocket..)
'sid
Last edited:
RustyRedneck
New member
What's your goal top speed?
I've done a little messing with gearing in the past and found that if you determine the speed you want to achieve at a certain RPM, it makes the results a lot attainable the first time around rather than having to rebuild something later.
So, you have a 9.5 inch tall tire, a 10 tooth clutch, and I'm supposing a stock 5 hp briggs which is probably governed for a speed of 3600 RPM. The main thing to figure out is how many RPMs the tire has to turn to achieve whatever speed you are going for. Or at least figure out how fast you'll go with the set up you have without running past a radar gun. So, a 9.5 inch tall tire has a circumference of 29.8 inches. With a 54 tooth sprocket on the drive wheel, you will have a 5.4:1 ratio of engine RPM to tire RPM. So, 3600/5.4 is 666.7 (sorry if you don't like that number) RPM. Now for the inches per minute traveled. 666.7x29.8=19,867.99 IPM. So, that equates to 1655.7 Feet per minute. Divide that by 5280 to get your miles per minute and we have 0.3135 miles per minute. Seems slow right, well considering you'd have to be doing 60 miles an hour to cover a mile in a minute, it's not that bad for a small tire go-kart. It's not very fast but it's still 18.8 MPH if my math is right. I hope my math was right and I hope this helps.
Engine RPM / total gear reduction = wheel RPM
Wheel RPM x tire circumference = IPM
IPM / 12 = FPM
FPM / 5280 = MPM
MPM x 60 = MPH
I think that's right. If I'm not, sorry. Please correct me.
I hope you have fun with your go-kart!
I've done a little messing with gearing in the past and found that if you determine the speed you want to achieve at a certain RPM, it makes the results a lot attainable the first time around rather than having to rebuild something later.
So, you have a 9.5 inch tall tire, a 10 tooth clutch, and I'm supposing a stock 5 hp briggs which is probably governed for a speed of 3600 RPM. The main thing to figure out is how many RPMs the tire has to turn to achieve whatever speed you are going for. Or at least figure out how fast you'll go with the set up you have without running past a radar gun. So, a 9.5 inch tall tire has a circumference of 29.8 inches. With a 54 tooth sprocket on the drive wheel, you will have a 5.4:1 ratio of engine RPM to tire RPM. So, 3600/5.4 is 666.7 (sorry if you don't like that number) RPM. Now for the inches per minute traveled. 666.7x29.8=19,867.99 IPM. So, that equates to 1655.7 Feet per minute. Divide that by 5280 to get your miles per minute and we have 0.3135 miles per minute. Seems slow right, well considering you'd have to be doing 60 miles an hour to cover a mile in a minute, it's not that bad for a small tire go-kart. It's not very fast but it's still 18.8 MPH if my math is right. I hope my math was right and I hope this helps.
Engine RPM / total gear reduction = wheel RPM
Wheel RPM x tire circumference = IPM
IPM / 12 = FPM
FPM / 5280 = MPM
MPM x 60 = MPH
I think that's right. If I'm not, sorry. Please correct me.
I hope you have fun with your go-kart!
Last edited:
RustyRedneck
New member
I missed writing down part of my formula. I just added it in. Might not be a bad idea to check my last post again.
18.84mph is correct for a 5.4:1 ratio and 9.5" wheels..
(well tyres are out of round once loaded, thus effective wheel diameter is a bit less yadda yadda...)
but the math is correct anyways (the initial assumptions might not be)
'sid
(well tyres are out of round once loaded, thus effective wheel diameter is a bit less yadda yadda...)
but the math is correct anyways (the initial assumptions might not be
)'sid
bob58o
SuckSqueezeBangBlow
I hate this. It takes all the fun out of it and it becomes another abstract formula. Here it is, BUT the learning comes from understanding it the way RRedneck describes it.
Cheater Formula (using only the most basic required information).
Multiply 4 things together, then divide by the 5th. Easy like Sunday Morning.
MPH =
(0.002975)*(Engine RPM)*(# of Teeth on Clutch)*(Diameter of Tire in Inches) / (# of Teeth Rear Sprocket)
For example...
((0.002975)*(3600)*(10)*(9.5)) / (54) =
18.84 MPH
Because I hate not knowing where strange numbers come from...
The constant 0.002975 comes from
((3.14159) * (60 min per hour)) / ((12 in per foot) * (5280 ft per mile))
And for completeness, 3.14159 is pi. May god have mercy on your soul if you didn't know.
I'm not really sure what a kilometer is and my watch doesn't read metric time, so sorry rest of the world. You can make your own cheater formula. LOL
Sine, Cosine, Cosine, Sine, 3.14159!!!!!
https://www.youtube.com/watch?v=5NgjkwQ-7lY
Cheater Formula (using only the most basic required information).
Multiply 4 things together, then divide by the 5th. Easy like Sunday Morning.
MPH =
(0.002975)*(Engine RPM)*(# of Teeth on Clutch)*(Diameter of Tire in Inches) / (# of Teeth Rear Sprocket)
For example...
((0.002975)*(3600)*(10)*(9.5)) / (54) =
18.84 MPH
Because I hate not knowing where strange numbers come from...
The constant 0.002975 comes from
((3.14159) * (60 min per hour)) / ((12 in per foot) * (5280 ft per mile))
And for completeness, 3.14159 is pi. May god have mercy on your soul if you didn't know.
I'm not really sure what a kilometer is and my watch doesn't read metric time, so sorry rest of the world. You can make your own cheater formula. LOL
Sine, Cosine, Cosine, Sine, 3.14159!!!!!
https://www.youtube.com/watch?v=5NgjkwQ-7lY
Last edited:
KM/H =
(0.001885)*(Engine RPM)*(# of Teeth on Clutch)*(Diameter of Tyre in Centimeters) / (# of Teeth Rear Sprocket)
For example...
((0.001885)*(3600)*(10)*(9.5)) / (54) = 30.32 KM/H
Because you hate not knowing where strange numbers come from...
The constant 0.001885 comes from
((3.14159) * (60 min per hour)) / ((100 cm per Meter) * (1000 M per Km))
And for completeness, 3.14159 is pi. May god have mercy on your soul if you didn't know.
or shorthand for the constant:
6 times Pi = 18.849555921538759430775860299677 (say 18.85)
divided by 10000
or sixty times Pi divided by 100,000 if you like...
You're not really sure what a kilometer is but we can say it's a much easier constant calculation nonetheless.
#triplezero1885
'sid
*whistling strolling off*
(0.001885)*(Engine RPM)*(# of Teeth on Clutch)*(Diameter of Tyre in Centimeters) / (# of Teeth Rear Sprocket)
For example...
((0.001885)*(3600)*(10)*(9.5)) / (54) = 30.32 KM/H
Because you hate not knowing where strange numbers come from...
The constant 0.001885 comes from
((3.14159) * (60 min per hour)) / ((100 cm per Meter) * (1000 M per Km))
And for completeness, 3.14159 is pi. May god have mercy on your soul if you didn't know.
or shorthand for the constant:
6 times Pi = 18.849555921538759430775860299677 (say 18.85)
divided by 10000
or sixty times Pi divided by 100,000 if you like...
You're not really sure what a kilometer is but we can say it's a much easier constant calculation nonetheless.
#triplezero1885
'sid
*whistling strolling off*
bob58o
SuckSqueezeBangBlow
If I learned anything from Chemistry it was Dimensional Analysis.
One of the most useful mathematical lessons ever learned.
Dr Bredemus made High School Stoichiometry pretty simple. He also ate a weighed piece of chalk and then measured the volume of his burp. And burned hard candy with a torch.
Thank you Dr Bredemus. Although your burp lost to Dr Cleary's tooth-stick bridge and egg drop, Chemistry was cool too. My favorite was Dr Tuenissen for English. Born in Indo-China (he was never specific), Lived in Germany and Amsterdam, Moved to US, Joined the Military, to teach English to HS kids. I've never seen a man so upset over a punctuation error. The disappoint in his face after discovering a comma spliced sentance would break you. But he would crack a smile as he returned the paper to you for you to do it over.
Don't watch. It's boring.
https://www.youtube.com/watch?v=DsTg1CeWchc
One of the most useful mathematical lessons ever learned.
Dr Bredemus made High School Stoichiometry pretty simple. He also ate a weighed piece of chalk and then measured the volume of his burp. And burned hard candy with a torch.
Thank you Dr Bredemus. Although your burp lost to Dr Cleary's tooth-stick bridge and egg drop, Chemistry was cool too. My favorite was Dr Tuenissen for English. Born in Indo-China (he was never specific), Lived in Germany and Amsterdam, Moved to US, Joined the Military, to teach English to HS kids. I've never seen a man so upset over a punctuation error. The disappoint in his face after discovering a comma spliced sentance would break you. But he would crack a smile as he returned the paper to you for you to do it over.
Don't watch. It's boring.
https://www.youtube.com/watch?v=DsTg1CeWchc
fasterSr
fasterSr
Cool! Now...can someone throw a jackshaft into the equation? Say increase from 18.8 mph to 37.4 mph with it?
ezcome-ezgo
G'me sumthin to write on
Cheating is fun. So are secrets. Dimensional analysis makes my day.
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