the phrases used to discus rear gear ratios are multiple, confusing and seemingly inconsistent..

can someone list the phrases and difine them

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Rich
Cocoa Beach, Fla
Team Chevelle #380
46 but feeling like 20 when i'm in my 70 SS 454
wa3men@aol.com
www.chevelles.com/showroom/70_SS_454.jpg (http://www.chevelles.com/showroom/70_SS_454.jpg)

I'll start. steep,low= a numerically high number such as 3:73 4:10 etc. Hiway,Tall=a low numeral ratio 2:10,2:73 etc Here's what can also be confusing someone refers to rearend being geared real low this is the same as steep, low in this sense refers to ratio not the numeric value. You'll find that a car with a low rear gear ratio will launch faster and reach a high engine rpm quicker, Top speed woould be limited by maxengine rpm, whereas a car with a highway gear would be slower off the line but hasnt reached his max rpm at the same point on the track(assuming both cars equal except for rear ratio :Confused:??

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PhilMullaly Member562 72camino TPI proj

the only thing that Id like to ad is that many many people get confused with where the ":" goes in the gear ratio number..

its 3.73 or 3.73:1 not 3:73

3:73 would indicate that 3 turns of pinion gear would turn the ring gear 73 times.. 3.73:1 means 3.73 turns of the pinion gear would turn the ring gear (or axles) one turn.. hope that clears things up its my pet peeve seeing it listed the wrong way

(no offense anyone just me being picky) http://www.chevelles.com/forum/smile.gif

good day

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Mike Reeh
Gold #34
San Diego, CA

Gear ratio: The number of times the pinion gear (driveshaft) turns per revolution of the axles (tires). It is expressed as x.xx to 1 or x.xx:1. The :1 is often ignored.

Example: 4.11:1 means the driveshaft turns 4.11 times just to make the wheels rotate once.


knipe
71elkss

Heck, there's nothing to add to this. We're done. You guys did perfect.

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Tom Parsons

i understand most of that

"someone refers to rearend being geared real low this is the same as steep, low in this sense refers to ratio not the numeric value"

above is an example of what i was getting at..."low in this sense refers to the ratio not the numeric value"...
the ratio IS the numerical value isnt it??...ie a 4.11:1 ratio (high ratio) is a 4.11 (high numerical)...so where does that come off being referred to as "low"

that is exacly what i dont get!!!!

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Rich
Cocoa Beach, Fla
Team Chevelle #380
46 but feeling like 20 when i'm in my 70 SS 454
wa3men@aol.com
www.chevelles.com/showroom/70_SS_454.jpg (http://www.chevelles.com/showroom/70_SS_454.jpg)

well if one gear is turned 60 revolutions and it rotates another gear only one revolution they would have a very high gear ratio (60:1)
Why it is called a low gear I guess is because of the output gear's speed.
That is a good question, why do they call high ratios low and low ratios high DZ ?
http://www.chevelles.com/forum/confused.gif

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Dean Call
Team Gold member #3
A.C.E.S. # 00235
N.C.O.A. # 4350
Mid America Chevelle Club (http://macc.chevelles.net) #001
chevelles.net (http://chevelles.net)

Lower ratio = higher number.

Im not sure but is is it called high because it has a high input, lets say 4.11, and a low output, because tires spin slower at high rpms. And then called low when it has a low input, 2.73, then called high cause of the huge output... not sure just taking a shot at it...

Hey Mike thanks I knew I'd botch it somewhere, nice catch Phil http://www.chevelles.com/forum/smile.gif

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PhilMullaly Member562 72camino TPI proj

Hey guys all you have to do is think backwards HIGH # LOW GEARS,LOW # HIGH GEARS.(IE 1to1, 1 turn in 1 out.100to1, 100 turns in 1 turn out)...FRED

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ok .. but that makes no logical sense...just seems to add confusion

Or so you though DZ!!! <BLOCKQUOTE>quote:</font><HR>Originally posted by DZAUTO:
Heck, there's nothing to add to this. We're done. You guys did perfect.
<HR></BLOCKQUOTE>

Try to put it in perspective this way. Your transmission has several gears, 1st or low gear through 4th or high gear. (assuming 4spd). Using my 700r4 as the example 1st is 3.07:1 (low gear) and 4th is 0.70:1 (high gear). It's the same at the rear as everyone else has stated. The only reason I brought up the trany is we all under stand high gear and going faster.

Why the world decided to call lower number'd ratios high gears and higher number'd ratios low gears plays out as high gear = high speed and low gear = low speed.

70 SS 454 - There may be a more sientific explanation starting with levers and fulcrums and such. Not sure you'll get it here though!!



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...DjD
69 Ragtop

WHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAT?

The way I always looked at it was low gear=low speed, high gear=high speed.

For example, a transmission. Low or 1st gear is a slow speed and 3rd or high gear is the fastest speed.
When the transmission is in 1st gear, you go slow but have lots of torque or pulling power.
When the transmission is in 3rd (or 4th) or high gear, you can go really fast but don't have much pulling power.
Same thing thing with a rear end. A low geared rear end (such as 4.11 or 4.56) doesn't let you go very fast, but has lots of pulling power from a stop (read drag race rear end).
A high geared rear end (2.73 or 3.08) lets you fly down the interstate, but you don't have as much power from a stop.

Otherwise-------------------------------I don't know!


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Tom Parsons

If you aint got it now you aint ever going to get it...FRED

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DZAUTO has been doing this stuff since they used to make the gears out of wood so I believe him.. http://www.chevelles.com/forum/biggrin.gif

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Mike Reeh
Gold #34
San Diego, CA

so,, the conclusion is that if some guy comes up to me and says
"its got low rear"

i then know no more than i did before he clued me in


ive got to ask
" you mean low gears (which would indicate 4 series) or low ratio (which would indicate 2 series) "


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Rich
Cocoa Beach, Fla
Team Chevelle #380
46 but feeling like 20 when i'm in my 70 SS 454
wa3men@aol.com
www.chevelles.com/showroom/70_SS_454.jpg (http://www.chevelles.com/showroom/70_SS_454.jpg)

Rich if its got a low rear it is not going the be fast BUT it will get there in a hurry.High rear the engine will turn slower on the hiway higher top speed BUT slower getting there.Thats it for me I don't know how to make it any clearer...FRED

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