Gear Ratios

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dknguyen

Well-Known Member
So it turns out I've been using the wrong terminology for gear ratios half the time.

I say gearing up for higher speed/low torque and gearing down for lower speed/higher torque, but then I say "high gear ratio" for lower speed/higher torque. So you "gear down" to get a "high gear ratio". I never noticed how inconsistent that was until now.

I should just look at the math:

Gear Ratio = Output/Input

THen it's dead obvious which is gearing up and higher, and gearing down and lower.

dknguyen

Well-Known Member
And when people refer to gear ratios as X:Y, it is input : output right? So a gear ratio of 10:1 is lower than a gear ratio of 5:1, and a 1:10 is higher than 1:5?

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tcmtech

Banned
You Got it! Mechanical terminology is just as ass back wards and F'ed up as electrical and electronics terminology.

I have a 10:1 gear reduction on my one transmission. I also have 10:1 gear up on my other transmission.
Either one is technically a correct description and would be clearly understood by someone that works with mechanical power train systems.

Banned
That's one of those convention things. Step up 10 to 1 would be 1 in 10 out, step down would be 10 in 1 out to me. It's a language preference only, state the whole 1:10 input to output ratio if you want to be specific. Speed vs torque it can be looked at oppositely as well, stepping up speed steps down torque and vs versa, so it's whatever you define it as.

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Boncuk

New Member
I guess it's a pretty easy thing and easy to remember, provided you own a car with manual gear box.

Switching gears up means a higher speed, hence a transmission ratio >1.

Boncuk

dknguyen

Well-Known Member
I guess it's a pretty easy thing and easy to remember, provided you own a car with manual gear box.

Switching gears up means a higher speed, hence a transmission ratio >1.

Boncuk
Yeah, it seems everyone says it differently so I'm looking at car gearboxes as the reference.

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