Author Topic: New Gears  (Read 4001 times)

Offline The_New_Guy

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New Gears
« on: January 24, 2015, 11:25:28 am »
Hey guys, I'm new here so I have a 1985 chevy truck with a granny gear 4speed. I'm headed to college soon so due to circumstances I'll be taking her on a close to 2 hour drive. And the truck is for sure not geared for that. Cause 70mph is about 3,000 rpm. I was wondering what gear recommendations y'all would have. Thanks!

Offline 78BIG-TEN

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Re: New Gears
« Reply #1 on: January 24, 2015, 11:36:37 am »
Depends on tire size,#.08 with 28 inch tires put my 78 at about 2600 at 70

Offline The_New_Guy

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Re: New Gears
« Reply #2 on: January 24, 2015, 12:28:45 pm »
I just have stock size 16 inch tall tires

Offline 78BIG-TEN

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Re: New Gears
« Reply #3 on: January 24, 2015, 03:18:34 pm »
So its a 3\4 or 1 ton.if so at that rpm probably has 4.10 in it

Offline zieg85

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Re: New Gears
« Reply #4 on: January 24, 2015, 05:22:52 pm »
2 hour drive becomes 2.5 hour drive at 55 mph.  More time to enjoy the scenery and a whole lot cheaper than a gear swap.  My $.02
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline The_New_Guy

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Re: New Gears
« Reply #5 on: January 26, 2015, 02:59:14 pm »
It has 4.33's by the original parts identification in the truck. And the truck does decent running at 65mph

Offline zieg85

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Re: New Gears
« Reply #6 on: January 26, 2015, 03:34:01 pm »
It has 4.33's by the original parts identification in the truck. And the truck does decent running at 65mph

Interesting, never heard of that ratio.  You sure?
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline Captkaos

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Re: New Gears
« Reply #7 on: January 26, 2015, 07:09:43 pm »
4.56 is the largest gear ratio you could get in 1985 and it was 3/4T or 1T only.  How did you derive at 4.33?  the ratio lower than 4.56 is 4.10.
We need more information on the truck to give a recommendation though
What axle? if it is 16's it has to be 3/4T up, so what tire size, what engine and what it the normal use?

Offline roundhouse

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Re: New Gears
« Reply #8 on: January 28, 2015, 07:22:14 am »
Taller tires are always cheaper than a gear swap

Or just drive slower on your trip

Never seen 4.33


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