Need help with disc/sprocket assembly

[5-7HEAVEN]

CrazyDan, good to know.

 

[Street Ryderz]

The product is the result of multiplying ALL the quotients, like we learned in school.
There is only one answer that matters, which is the final gear ratio.
The fraction is 11t divided by 30t, not 30t divided by 11t. You should run your numbers thru online calculator. You'll see that multiplication rules, not addition.

Wait what? It's not a fraction,it takes 2.72 turns of the 11 t gear to rotate the 30t gear once,if it were .367 we would be going a heck of alot faster no?

 

[5-7HEAVEN]

Gearing from engine to chainring reduces rpm from 5,000 rpm to 500rpm or less.
Drivers are USUALLY small gears who chain up to a larger gear. They create a lower
(higher numerically) gear ratio.
For example, the first driver is the 10t crank sprocket. It'spinning at 5000rpm. At the first jackshaft pulley with 20t, rpm drops in half(10t/20t), to 2500 rpm.
A 9t jackshaft sprocket connects to a 45t chainring sprocket. Its 5:1 gearing(45t/9t) drops the 2500rpm to. 500rpm.
Now the chainring sprocket which links to the hub might be larger OR smaller than the hub sprocket. My chainring driver has 24t and my First gear has 36t. That's 1.5:1 reduction(36t/24t). On my bike, rpm is further reduced to 333rpm.
So 5000rpm/333rpm = 2 x 5 x 1.5 = 15:1 gear reduction.
You'd be off if you added the gear reducers, like 2 + 5 + 1.5 = 8.5:1....
5000rpm/8.5 = 588rpm, which is incorrect.

The 30t drives the 11t, not the 11t driving the wheel hub. With the chainring and rear wheel hub sprockets, the hub sprocket is always the numerator(top number) in the division equation.
Use the online calculator.

 

[Street Ryderz]

With the chainring and rear wheel hub sprockets, the hub sprocket is always the numerator(top number) in the division equation.
Use the online calculator.

What chain ring? 11 t on the engine 30t on the wheel,single speed one chain so yeah 30 divided by 11 = 2.72 pretty simple.

 

[5-7HEAVEN]

I can see why you're confused with the 11t/30t.
Everyone's conditioned to think that all small sprockets drive the larger sprockets.
However, if you sit in front of the bottom bracket and spin the pedals, you'll realize that the 30t chainring is the driver. It spins the 11t.
When that happens, gearing INCREASES, not reduces.
I learned this in middle school. It stuck with me for 60 years.

 

[5-7HEAVEN]

I'm done.

I'm sorry. You had me confused, when you added the 3.1 and 3.8.

 

[Street Ryderz]

I can see why you're confused with the 11t/30t.
Everyone's conditioned to think that all small sprockets drive the larger sprockets.
However, if you sit in front of the bottom bracket and spin the pedals, you'll realize that the 30t chainring is the driver. It spins the 11t.
When that happens, gearing INCREASES, not reduces.
I learned this in middle school. It stuck with me for 60 years.

I'm not confused with any of it other than making a mistake of adding not multiplying the example figures for a jackshaft,the 11/30 gearing is the single speed setup I compared it too! You got confused and still are I guess because as I've tried to explain there is no chainring in that equation and the little gear 11t IS driving the the large gear 30t and that ratio of 2.72 is correct my wheel is not driving the engine LOL.

 

[larrythelabelguy]

Finally figured it out...

 

[Member 30571]

Nice bike...

 

[5-7HEAVEN]

I'm glad for you