4x4 Gear ratio ideas?
 

I am in the process of building a 1970ish (lots of years) short bed 4x4. The axles I have appear to be 3.08s (by turning the pinion and counting). The question is.... will these gears spin 33" tires with a standard trans.? It's not going to be a rock crawler...just a driver. I'd like to be able to just drive it to work like a human. Any one have any experience with gears this high on the street with big rubber? I see no need for 4.10s and listening to the engine screaming down the highway.
Thanks

Re: 4x4 Gear ratio ideas?
 

yes they will. but you could also do it with a 5hp briggs.

it realy depends on your motor.

Re: 4x4 Gear ratio ideas?
 

Which trans?
With a 465 you will proably get to use 1st. But you'll see better mileage as well.
I had a 700r4 and 3.08s with 33"s. That didn't work out so well.

Re: 4x4 Gear ratio ideas?
 

IMO 4.56 is a minimum for the 33" and up rubber you are runnin.

My 4 speed 68 K20 burb is runnin 4.57's with 33" tall BFG's, and it drives very nice to me.

My 02 yota 4x4 with 31" tall tires with 4.56 gears, runs a bit high rev but it is a 5 speed so it's all good to me.

4.11 may squeek by as a DD that never see's the dirt or serious work, and is just a run around rig meant to just look like a 4x4.

Anything taller than 3.70's and you will be driving a dog of truck and get terribly MPG on top of that.

Re: 4x4 Gear ratio ideas?
 

Mine is 3.08 with 33's, it's not bad running around, but wind up in 3rd on the steeper grades around here.
Max

Re: 4x4 Gear ratio ideas?
 

4.56 and 33 with a v8 is stupid. i have 4.56 with 38" and its to slow for the rpm.

with a 33 you will be just fine with a 3.73.

Re: 4x4 Gear ratio ideas?
 

i run a 4.10 with 33's and love it! drives great on the highway, drove it 800 miles one way last summer. got 12 mpg tho....not great but not awful either

Re: 4x4 Gear ratio ideas?
 

I have to agree with 2tons of fun on this one. I started out with 3.08's and 33's with a 465 and a 350 and it worked ok(thanks to the granny low). Then went to a 427bb wich worked really well with the extra torque. And later I switched to 3.73's and I was almost just as happy with the 3.08's as i was with the 3.73's the only real benifit was it didn't labour so hard going up hills on the hiway. I think if you have a small block 4 speed then 3.73 is the better choice. But with a big block then 3.08's will work. What are you running for an engine?

Re: 4x4 Gear ratio ideas?
 

I have 33's on my truck with 3.07's and a th350 with a mild 350 and it is OK, I beat my buddies brand new F-150 in a drag. I am going to switch to at least 3.73's though it will be way more fun!

Re: 4x4 Gear ratio ideas?
 

All the guys runnin 3 what evers with tall tires, and especially automatics... I'll make all kinds o' cash pullin you're stuck butts out of the sand/mud/hole

But if you just want to get down the road then that is different story, I just wouldn't want to be behind you when you are goin up a hill or pulling a trailer.

If you run that combo in a 4x4 with tall tires, and actually want to put true effecient HP/Torque then low gear is the best.

4.56 and a 33" tall tire stupid? Then I guess I am, but I am still driving and pullin you.

Re: 4x4 Gear ratio ideas?
 

im runin 4.10s with 35's and have no problem off road...

Re: 4x4 Gear ratio ideas?
 

This is a battle that could go on forever. The option that a lot of guys are not looking at is the addition of MORE gears, not just higher or lower. If you take the good ideas above and melt them all together, you need low end for some good off roading, and overdrive for cruising, yet you still need a 1:1 on the highway for the bigger hills. So look into adding more gears via a 4 speed auto or 5 speed manual with O/D and you'll have the most drivable truck around.

Re: 4x4 Gear ratio ideas?
 

My truck never sees off-road action. 250HP 350 th350 with 33s and 3.07 gears. It works great as a driver, doesn't have much on the low-end though, it feels like if I'd get a cam and such in the engine to get 350HP or so out of it it'd probbably be better. But, once you get it rolling on top of those gears and the tires it pulls up to 70mph without blinking. Heck at 60 I'm barely turning over 2k RPM.

Re: 4x4 Gear ratio ideas?
 

In my old k30 i had 4.56 and 44" tsl's. No way were you pullin me around. 33's and 3.08 are pretty close to 4.56 and 44's. My 71 now has 37's and 4.10s. the old 396 hauled arse and the new 496 will be just insane. Alot depends on your motor

Re: 4x4 Gear ratio ideas?
 

First of all, calling people "stupid" is not acceptable. Opinions are fine but negitivity like that is considered trolling...and against the rules.

(Fair warning given)


As for my opinion, gearing is very important to performance. It is part of a correctly assembled "package". It matters as much as the proper cam and torque converter combination.
Sure the truck will move with nearly any mess of parts....but is that what you really want?

As the tires get taller the gear ratio has to get lower compensate....and that is just to maintain status quo, assuming that it was somewhat right in the first place. Of course this is limited to available gear ratios, so the is some "play".

Just because "the factory did it" or it was an "available option" doesn't make it right. Heck the factory put 2.73s in a lot of trucks w/overdrive no less?....and 2.56 was available, just to make it worse, if you think you need to?

I have replaced a lot of gears for people over the years and every one of them was amazed at the difference it made. Most of them said that it was "not the same truck" or something to that effect. It's all about the right combination.


Yes, plenty....and the whole point is that it won't be "screaming" with a tall tire.

Re: 4x4 Gear ratio ideas?
 

It maybe be a little slow off the line but it will work for good gas mileage compared to some.

Re: 4x4 Gear ratio ideas?
 

if its a slow race or a pull off you want then lets rock. cause scooter, you got nothin on me.

Re: 4x4 Gear ratio ideas?
 

Cool your jets turbo... :lol:

I wasn't callin anyone out to a "race", and your call out to me is laughable.

I simply pointed out the obvious, when buidling an effecient and capable 4x4 with tall tires.

Being called "stupid" and challenged to a "race" in this thread of oppinion.. Wow, ok - whatever. :smoke:

Re: 4x4 Gear ratio ideas?
 

That is not necsesarily so, I you are cruising too low in the RPM range of your engine, it is not helping fuel mileage. General city driving with a gear ratio that is too high will cause you to drive deeper into the throttle just to get going, which hurts fuel mileage too. Optimum RPM range is best, even if it is a bit higher than most think.

Re: 4x4 Gear ratio ideas?
 

http://www.currieenterprises.com/ces...Calculator.htm

Try these calculators to figure it out.

Re: 4x4 Gear ratio ideas?
 

I firgured I would have to rev to 6000 for a long time to get to 150mpg, i found what i want to do.:buh::burnout::ack::bomb:

Re: 4x4 Gear ratio ideas?
 

i'm running 3.73's on 35's with a 454

no problems, but i spin around 3500 at 115 kph. (70 mph)


oh yeah... th 400

Re: 4x4 Gear ratio ideas?
 

I think 3.73s will be your best bet. I really liked them with my 35s. I had a stock motor and the rpms worked out really well for me. I cruised at 75. I put 3/4 tons in they had 4.10s I loved that gear ratio with 38s. Once again allowed me to cruise at 75 all the time. I got 10 mpg with the 38s.