Pulley to Gear Ratio

What max. torque & speed are you transmitting?

14/1.75 = 8.00 (exactly). Assuming the pulleys were described as pitch diameter, this would be your desired ratio. Consider also that a gear drive will likely need to be lubricated, whereas belt drive would not.

In addition to the above, bear in mind that with pulley drive, the driven shaft will run forwards. If 2 gears are substituted, the driven shaft will run sdrawkcab.

I'm going to need someone who types r-e-a-l-s-l-o-w to explain this one to me.

-A-

! w-o-h s-i s-i-h-t (hold up to mirror).

Yeah, wow. Thanks "guest."

Not the backwards writing. The idea that changing from (assuming v-belt) pulleys to gears reverses direction.

-A-

I believe the poster ment to write sprockets rather than gears, as I've never seen a gear driven go-cart have you?

Ooohh, GEARS! As in Gear drive! As in, vastly more complicated than I had considered. This whole time I was thinking sprockets and CHAIN drive to replace the pulleys and belt. Because that makes sense.

OK, thank you for clearing my addled brain.

OP. I trust you intend to replace a belt drive with a chain drive, correct? Otherwise, yeah, stay the heck away from gear drive. Too complicated and it'll reverse your drive direction.

-A-

Change the small pully to 2.3 inch diameter.This will give 6 to 1 ratio you need.

A lot less problems than gears.

Hi Guest,ok now lets be sensible, driving with gears or cogs is no great problem,(apart from lubrication)You have only to look at the humble bicycle,to see the principle.It is obvious that when "meshing cogs" they change the direction of rotation.eg; 2 cogs will result in the output cog rotating in reverse, 3 cogs maintains the original direction.

You have only to look at the humble bicycle,to see the principle.

Given that humble bicycles do not routinely have exposed cogs, especially with idler cogs, perhaps a lathe would give a better indication, unless the guest can find a disassembled gearbox lying around. One would hope that your drawing alone would do trick, however.

I'd take the reference to go karts to mean that he is really interested in sprocket-and-chain drive. I gather he may be unaware of the means to calculate reduction ratio, given that his existing ratio is 8:1 rather than 6:1. He might need to know that the reduction in a chain or gear drive can be had just by forming a ratio of tooth counts. If he lives in the US, Grainger is one supplier of chains and sprockets, and a # 40 chain with matching sprockets of 10 teeth and 60 teeth would perhaps suit his needs, if he is not too concerned that a 10 tooth sprocket is a little on the small side for optimum efficiency.

20 tooth pinion (CW/CCW), 80 tooth idler (CCW/CW), 160 tooth output (CW/CCW).

...of course he did say that he wants a 6:1 ratio, not 8:1.

Hi Blink,

I realise the OP said they want to change to a 6 to 1 ratio.

But, the OP also said the current set up, which they give sizes on, is about 6 to 1. But in fact it is 8 to 1.

If they work from what they think they have (6 to 1) rather than what it is in fact (8 to 1) the resultant speed could be very roughly 25% too fast.

I am not being nit picking, they need to know the actual speed they have before they can judge what ratio to change to.

Take care

The OP didn't actually say WTF he wants - it could be read as "I want about 6:1", or "I want about the same as I've got now" (which he thought was ≈ 6:1, but we know is 8:1).

As he didn't bother to come back & respond, it's all pretty academic.

Hi JohnDG,

Cheers for what you said in post ＃19.

I would also add, this respondent is a "Guest", and as such we have no idea who he/she is.

Take care.

Yes, by all means lets be sensible.The OP said gears, not sprockets.Belts are less troublesome than gears for some applications, sprockets are better for others, and gear boxes are better for other applications.The most economical method to achieve the OP's desired ratio is to simply change the size of the small pulley.

Hi Guest,

Just a quick point.

The ratio between the 14" (~350mm) and 1¾" (~43mm) is ~ 8.14..........

Hope this help if but a little.

Take care

14 divided by 1.75 = 8.0 exactly

14 inches = approximately 350 mm (355.600712)

1.75 inches= approx. 43 mm (44.45008890)

355.600712/44.45668890= 8.000000018

Much simpler with inches in this case.

Just my humble opinion guys, but this may being blown out of the water somewhat.

Lets look at the original post again rather than simply looking at the faults in each others solutions and over analysing the problem at hand.

Might be time to move on, at least until the OP can get back and better specify what he/she wants after goggling a gear and sprocket...

I that this has went so far left due to the Ops original incorrect statements that he/she wont even think about returning to the discussion for fear of ridicule.