Gear ratio problem.. Help me figure this out.. lol

[Eli]

Ok, here's the problem.. I'm trying to figure out the final gear ratio on my scooter.. and am not quite sure how to do it.

The engine has a 10 tooth sprocket, and the primary drive on the jackshaft has a 52 tooth sprocket, That's 5.20:1

The secondary drive on the jackshaft has a 9 tooth sprocket, and the tire has a 20 tooth sprocket. That's 2.22:1.

How do I figure out the final drive? Is it just 5.20 + 2.22 = 7.42:1?

lol.. I suck at math.. lol

 

[Eli]

Oh, comeon.. there's gotta be someone that knows, lol..

 

[Mr.IncrediblyBored]

Page 3 might be of use.

Where it says "To Determine Final Drive."

More info here:

<< FINAL DRIVE RATIO
The number of turns the rear wheels make in relation to the number of turns the drive shaft make. >>

I just spent a few minutes on Google. You may be able to find more info with some more time. I'm going to bed.

 

[Gonad the Barbarian]

5.20/2.22=2.477

I think that's right.

 

[Zenmervolt]

I thought you multiplied the ratios...

ZV

EDIT: Yeah, division doesn't work, has to be multiplication. If you have a 1:1 drive and a 2:1 final drive, then the overall ratio is 2:1. Same if you have a 2:1 drive and a 1:1 final drive. Multiplication gives 2:1 overall ration both times, but division gives 2:1 in one case but 1:2 in the other case.

 

[Eli]

Hmm.. so then it would be 5.20 * 2.22 = 11.54:1?

 

[Zenmervolt]

<< Hmm.. so then it would be 5.20 * 2.22 = 11.54:1? >>

I think that's right. It's amazing how much of a reduction there is in the drive on a scooter/moped.

ZV

 

[Eli]

Yeah, that sounds about right I guess.

And yeah, it is quite a bit.

It's not really a moped.. it's a goped.. hehe.. but goped is a brand, so proper is.. scooter? motorized scooter.. hehe..

Hawk pics..

I'm going to put a different engine on it, but will need to change the gear ratio to something a little more realistic(lol, like 7:1)... so am just figuring everything out.. hehe..