What gears?

GKM007 · Oct 13, 2015

I have run through a few tire size/gear calculators online and seems to have a decent idea where to head, but wanted some advice to backup what the calculators are telling me.

Durasparked 2.8
C5
current gears 3.45

Plan:
3 inch JD lift
31x10.50x15 tires

The calculators tell me with my current setup moving to what I want to run should be a 3.95

I should be aiming for 4.10's correct?

RonD · Oct 13, 2015

It depends on where you will be driving the most.
C5 is a 3 speed with no overdrive, so 3rd is 1:1 ratio
With 3.45
31" tires
at 65mph
engine RPMs will be 2,450

2.8l has peak torque at 2,600rpm

With 4.10
31" tires
at 65mph
engine RPMs will be 2,900

If you do mostly highway driving then stay with 3.45 or 3.73, if you want more low end power go with the 4.10

With 3.73
31" tires
at 65mph
engine RPMs will be 2,650

4x4junkie · Oct 14, 2015

Yeah I tend to agree with 3.73 also if you spend a lot of time on the highway @ 65 or faster, otherwise 4.10 (if you had OD w/lockup converter, I'd then say 4.56 no matter what).

redhurricane · Oct 14, 2015

4.10's will be hard to come by if you have the D35 front. they are pricey for new, and only came in 91-92 rangers with the D35 front. I don't believe 4.10's are out there for the D28 at all. If you are going to spend little time at highway speeds, and most at crawling/offriad speeds, I would also agree with 4.56.

alwaysFlOoReD · Oct 14, 2015

I have personally owned 4:10 for the d28. They were in an 87 stx hirider I scrapped out. I also bought a used set, front and back d28 and 7.5" with 4:10 that I installed in my b2.

Sent from my XT1032 using Tapatalk

GKM007 · Oct 14, 2015

It will see a little of both highway and off road. Nothing to serious in the off road department.

Someday I would like to 8.8 the rear and SAS the front, that will change this discussion entirely!

So for 31's aiming for a 3.73. What if I bumped up to a 33? I know the Dana 28 should not be running 33's by what most say. Assuming I can grab a Dana 35, will 3.73 still be an okay range for a 33?

I should be able to find 28/7.5 3.73 fairly easy.

redhurricane · Oct 14, 2015

I stand corrected on the D28 4.10:1 information.

3.73 will be very tall with 33's. bronco in my avatar had 33's with 4.56:1 and even that seemed a bit tall for my liking. 2.9L engine in that one.

4x4junkie · Oct 14, 2015

4.10 D35 gears currently $269.95
http://www.jamesoaksenterprises.com/index.php?main_page=product_info&cPath=36_387_398_412&products_id=1261

Sure, that's more than the others, but not absurdly so.

Agreed, 3.73 will suck with 33s. If you think you want 33s, then 4.10 would be better for sure.

You might also give some thought to whether you might ever swap to an OD trans at some point (maybe even with a 4.0L too)... If so, then I'd probably suggest getting that out of the way first, and then gear accordingly, 4.56 or 4.88 depending, as regearing axles again isn't cheap or always practical.

turbo91xlt · Oct 15, 2015

31s & 4.10s is perfect, if you want bigger tires go 4.56. Remember, don't fear the gear :icon_thumby:

GKM007 · Oct 16, 2015

My main concern is the C5 and only having 3 speeds. If I had a 5 speed I 'd worry a little less, since there are two more gear choices. I just don't want to over rev the motor and lose a ton of mpg, currently I get about 17 out on the freeway, not to bad for a 258k and 3 speeds. I need to hook up the tach that I bought from Orielly's to see what my revs are before I change out tire gear combo, what ever it is at now is what I want to shoot for.

I am having a really hard time trying to figure out the combo I want.
32x11.50 6 inch lift
or
31x10.50 3 inch lift

I feel like if I go 31 4.10 would prob be okay and 32's I would prob want a 4.56? I am not to worried about being under powered, its already slow just don't want to make it worse. Although the duraspark I am doing Saturday morning should definitely help

What gears?

GKM007

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RonD

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