# whats the equation for crawl ratio?

Discussion in 'The Garage' started by 84gmcjimmy, Nov 7, 2004.

1. ### 84gmcjimmy1 ton status

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I have 1 saved on the internet, but I want the equation, not the acutal calculator. Most of the calculatos don't use doublers, etc. for them.

I'm trying to figure out the ratio of:
th-400, 203/203/205 and 5.13 gear ratio.
Anyone have the eqation?
How do I figure it out for atlas or a klune v?

2. ### 70~K51/2 ton status

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[ QUOTE ]
I have 1 saved on the internet, but I want the equation, not the acutal calculator. Most of the calculatos don't use doublers, etc. for them.

I'm trying to figure out the ratio of:
th-400, 203/203/205 and 5.13 gear ratio.
Anyone have the eqation?
How do I figure it out for atlas or a klune v?

[/ QUOTE ]
2.48x2x2x1.96x5.13 = 99.74 for the trans, tc, tc, tc, and gears you listed.

3. ### atho1/2 ton status

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just multiply your lowest transmission gear by the low range in your transfer case(s), then the axle ratio. I have also heard that you get another 2x from torque converter slip in autos.

4. ### 84gmcjimmy1 ton status

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[ QUOTE ]
[ QUOTE ]
I have 1 saved on the internet, but I want the equation, not the acutal calculator. Most of the calculatos don't use doublers, etc. for them.

I'm trying to figure out the ratio of:
th-400, 203/203/205 and 5.13 gear ratio.
Anyone have the eqation?
How do I figure it out for atlas or a klune v?

[/ QUOTE ]
2.48x2x2x1.96x5.13 = 99.74 for the trans, tc, tc, tc, and gears you listed.

[/ QUOTE ]

yikes, thats still not very good.
Whats the numbers I would use for an atlas and a klune-v ?

5. ### big pappa b3/4 ton status

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Just get rid of the TH400 and go SM465...all the crawl ratio you need

6. ### 84gmcjimmy1 ton status

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[ QUOTE ]
Just get rid of the TH400 and go SM465...all the crawl ratio you need

[/ QUOTE ]

Nah, I already have the th-400, and I want an auto anyways.
I guess I'll be fine.

7. ### jac66951/2 ton status

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[ QUOTE ]
... 99.74 .... yikes, thats still not very good...

[/ QUOTE ]

Can you explain why that isn't a good crawl ratio for an auto? /forums/images/graemlins/confused.gif

8. ### big83chevy4x43/4 ton status

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[ QUOTE ]
[ QUOTE ]
... 99.74 .... yikes, thats still not very good...

[/ QUOTE ]
Sure. /forums/images/graemlins/smirk.gif

Kid, step away from the computer and go 'wheeling, for a change.

[/ QUOTE ]

i agree, 99.74 is alot moer than alot of people on this site.

if you had 2 vehicles with the same crawl ratio and tires, one a stick and one an auto, the auto will go slower. you have to remember the torque converter. there is no way that i know of to find the ratio of the converter, but also remember that it changes with the rpm.

9. ### m j1/2 ton status

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crawl ratio doesnt change with a convertor
convertor slippage is not the same as crawl ratio
one could slip a clutch and go slower as well

10. ### 70~K51/2 ton status

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[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
I have 1 saved on the internet, but I want the equation, not the acutal calculator. Most of the calculatos don't use doublers, etc. for them.

I'm trying to figure out the ratio of:
th-400, 203/203/205 and 5.13 gear ratio.
Anyone have the eqation?
How do I figure it out for atlas or a klune v?

[/ QUOTE ]
2.48x2x2x1.96x5.13 = 99.74 for the trans, tc, tc, tc, and gears you listed.

[/ QUOTE ]

yikes, thats still not very good.
Whats the numbers I would use for an atlas and a klune-v ?

[/ QUOTE ]
Depends on which ratio Atlas you use. Now if you put the low 1st gear kit in the TH400 with a Klune and a 5.0 Atlas you'd have this....
2.75x2.73x5.0x5.13 = 192.57 I think someone makes a 3.00 first gear for the TH400 too. /forums/images/graemlins/thinking.gif

11. ### big83chevy4x43/4 ton status

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i know that a converter is not the same as crawl ratio, but it does slip and it does alow you to go slower.

yes you can do it with a clutch but after a while the cluch will burn up, the torque converter is made to slip.

12. ### ntsqd1/2 ton status

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Torque multiplication varies with the design of the converter's vanes. 2:1 is a reasonable generic number. So if the gears multiply to 99:1 and you operate the engine below the converter's stall speed you should have at least 198:1 (effective) and possibly more.

The TH-425 converters originally put in the GMC M/H's have a 2.6:1 multiplication ratio. This was done b/c of the 3.08 final drive, 235R16 tires, and a 12,000 lbs. M/H. Good luck finding one. Most parts books list it as being the same as the other TH425 converters.

13. ### m j1/2 ton status

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you read "torque multiplication" to equal "gear ratio"?

14. ### dremuOfficious Thread DerailerPremium MemberGMOTM Winner

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[ QUOTE ]
you read "torque multiplication" to equal "gear ratio"?

[/ QUOTE ]

Sure. Gearing down 2:1 multiplies torque 2:1, right?

-- A

15. ### 84gmcjimmy1 ton status

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[ QUOTE ]
[ QUOTE ]
... 99.74 .... yikes, thats still not very good...

[/ QUOTE ]

Can you explain why that isn't a good crawl ratio for an auto? /forums/images/graemlins/confused.gif

[/ QUOTE ]

I meant is isn't good compared to a stick. I know I am comparing apples and oranges when talking about auto and manual...
Isn't a stick with a 205, the same ratio as a auto with a doubler? /forums/images/graemlins/frown.gif

16. ### 84gmcjimmy1 ton status

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[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
I have 1 saved on the internet, but I want the equation, not the acutal calculator. Most of the calculatos don't use doublers, etc. for them.

I'm trying to figure out the ratio of:
th-400, 203/203/205 and 5.13 gear ratio.
Anyone have the eqation?
How do I figure it out for atlas or a klune v?

[/ QUOTE ]
2.48x2x2x1.96x5.13 = 99.74 for the trans, tc, tc, tc, and gears you listed.

[/ QUOTE ]

yikes, thats still not very good.
Whats the numbers I would use for an atlas and a klune-v ?

[/ QUOTE ]
Depends on which ratio Atlas you use. Now if you put the low 1st gear kit in the TH400 with a Klune and a 5.0 Atlas you'd have this....
2.75x2.73x5.0x5.13 = 192.57 I think someone makes a 3.00 first gear for the TH400 too. /forums/images/graemlins/thinking.gif

[/ QUOTE ]

Ah, so I can buy gears for the th-400 to make it slower too? /forums/images/graemlins/yikes.gif

17. ### ntsqd1/2 ton status

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[ QUOTE ]
you read "torque multiplication" to equal "gear ratio"?

[/ QUOTE ]

Yes. You think it's different?

18. ### 84_Chevy_K10Banned

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[ QUOTE ]
[ QUOTE ]
you read "torque multiplication" to equal "gear ratio"?

[/ QUOTE ]

Yes. You think it's different?

[/ QUOTE ]

I think what he's getting at is that a slipping torque converter doesn't offer any gear reduction or torque multiplication. It's turning power into heat instead of putting it to the wheels.

19. ### RustBuket1/2 ton status

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I agree with tim. However, it does affect the final ratio but the *torque* output isn't affected. Gears are not the same as a viscous fluid. The extra power used to make the extra turn is given off in heat and not in power. So, you'll go slower but have the same power is how I see it.

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