Bigger tires
Lead Driver
Joined: Sep 2002
Posts: 9,555
Likes: 2,035
From: North Texas
I have that gearset in the 92, but I kept the stock size 235/75R15s. I bet it would be a slug as it is an extended cab too.
Kept my old 3.55:1 from the '88 which I am going to pop in it. Should wake it up quite a bit.
Kept my old 3.55:1 from the '88 which I am going to pop in it. Should wake it up quite a bit.
Lead Driver
Joined: Jun 2021
Posts: 5,221
Likes: 805
That's the code for 3.08:1 gears, open differential.
I wouldn't go bigger than 31" unless willing to regear. Good 31" tires and some tire chains on standby in the bed would be a good approach in my opinion.
If you want bigger tires and significantly more capability, regear to 4.10:1 and run 33" tires. During the regear, stuff an Eaton Trutrac rear differential in there. Night and day difference in capability of the truck. Note the front regear is dead simple: go to junkyard, and get a D50 ttb third from a truck with 4.10 gears. Your existing axle shafts will work, along with existing drive shaft. Install Moog cc824 front coil springs, and get an alignment. You'll hardly recognize the truck! Of course, that's much more work, may be out of the question.
I wouldn't go bigger than 31" unless willing to regear. Good 31" tires and some tire chains on standby in the bed would be a good approach in my opinion.
If you want bigger tires and significantly more capability, regear to 4.10:1 and run 33" tires. During the regear, stuff an Eaton Trutrac rear differential in there. Night and day difference in capability of the truck. Note the front regear is dead simple: go to junkyard, and get a D50 ttb third from a truck with 4.10 gears. Your existing axle shafts will work, along with existing drive shaft. Install Moog cc824 front coil springs, and get an alignment. You'll hardly recognize the truck! Of course, that's much more work, may be out of the question.
Lead Driver
Joined: Jun 2021
Posts: 5,221
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If 2 speed rear ends were all the rage.being able to shift on the fly the rear ratio would be cool
Lead Driver
Joined: Jun 2021
Posts: 5,221
Likes: 805
Thgis is not a direct comparison but see these BFs on this GMC. the squared shoulder and the white letering ultimately make the tire more pronounced, but its not technically even as tall as it was OE!
Thiks wheel is not turned forward so its a little less obvious.. but that tire "fuller" if you go by size. but its narrow and its got tread that retreat more than on the BFs
Hotshot
Joined: Jun 2015
Posts: 12,880
Likes: 2,446
Your current metric tire is 29” so going to a 31” tire effectively reduces your rear axle ratio to a 2.88 gear. If your thought the truck was a dog starting from stopped it will be worse.
I had 3.55 gears and kept the 235/75 tires but went with a LT (light truck) tire instead of the P (passenger) rating.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Unfortunately you have one of the least desirable combinations known to mankind. Why in the world Ford offered 3.08 gears in any truck is beyond comprehension.
Even stock height tires are a strain let alone anything taller. Your quest for taller tires is going to result in even less performance or a significantly thinner wallet sorry to say.
Even stock height tires are a strain let alone anything taller. Your quest for taller tires is going to result in even less performance or a significantly thinner wallet sorry to say.
Thread Starter
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Tuned
Joined: Feb 2022
Posts: 301
Likes: 30
From: Perth Ontario
Unfortunately you have one of the least desirable combinations known to mankind. Why in the world Ford offered 3.08 gears in any truck is beyond comprehension.
Even stock height tires are a strain let alone anything taller. Your quest for taller tires is going to result in even less performance or a significantly thinner wallet sorry to say.
Even stock height tires are a strain let alone anything taller. Your quest for taller tires is going to result in even less performance or a significantly thinner wallet sorry to say.
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Cargo Master
Joined: Mar 2010
Posts: 3,342
Likes: 294
From: Laramie, WY
Generally yes, fuel economy will drop.
I imagine the truck is slow being a 4.9L to begin with. Do you tow or haul much with the truck? If it's just a tooling around rig you use to go fish, I wouldn't worry about a being a little slower yet. But if it's your daily driver, needs to keep up in traffic, city driving, tow rig etc. May be better served with staying with the 29" tire.
There aren't any options to go 31" tall but narrower than 10.5", as far as I'm aware. Narrower is typically lighter, which I've read helps. But it has no impact on effective final drive ratio.
I imagine the truck is slow being a 4.9L to begin with. Do you tow or haul much with the truck? If it's just a tooling around rig you use to go fish, I wouldn't worry about a being a little slower yet. But if it's your daily driver, needs to keep up in traffic, city driving, tow rig etc. May be better served with staying with the 29" tire.
There aren't any options to go 31" tall but narrower than 10.5", as far as I'm aware. Narrower is typically lighter, which I've read helps. But it has no impact on effective final drive ratio.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
To do up-sized tires properly you need to change the gearing. That is the meaning behind thinner wallet.
Hotshot
Joined: Nov 2017
Posts: 17,500
Likes: 2,777
From: Northern Ontario
Lead Driver
Joined: Jun 2021
Posts: 5,221
Likes: 805
If it were me, I'd be looking at a good set of narrow dedicated snow tires. If you're running ice or lakes, I'd also look into a set that are studable. Imho, I wouldn't worry about the height - an extra inch is an extra inch. But the extra 1" you're going to gain isn't going to amount to much more clearance anyway.