73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: The_New_Guy on January 24, 2015, 11:25:28 am

Title: New Gears
Post by: The_New_Guy 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!
Title: Re: New Gears
Post by: 78BIG-TEN 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
Title: Re: New Gears
Post by: The_New_Guy on January 24, 2015, 12:28:45 pm
I just have stock size 16 inch tall tires
Title: Re: New Gears
Post by: 78BIG-TEN 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
Title: Re: New Gears
Post by: zieg85 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
Title: Re: New Gears
Post by: The_New_Guy 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
Title: Re: New Gears
Post by: zieg85 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?
Title: Re: New Gears
Post by: Captkaos 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?
Title: Re: New Gears
Post by: roundhouse 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


Sent from my iPhone using Tapatalk