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5.13s and 35s?

I

Incredible Hulk

NAXJA Forum User
Location
Burnsville, Minnesota
I have 97 with an AW4 and am currently running 4.56 and 35s. Works great offroad. I am swapping in a waggy 44 with 5.13s already in it, so I have to decide if I want to change the front gears to 4.56 or the rear to 5.13 and I am having a hard time telling myself I should put in 4.56 again. I will go to 37s eventually, but it wont be for a few years probably. So, first off, where can I find that RPM finder, and has anyone on here run 5.13s and 35s before? How'd she go? Thanks.
josh
 
I was running 5.13's and 35's, and it was just the right gears. I had 4.56's before, with both 32's and 33's. 4.56 was a good ratio for the 32's but with the 33's I wished I had 4.88's. Now with 37's I can't wait to get the stroker motor installed.

With the 5.13's and 35's I turned about 2400 rpm at 65 and about 3000 rpm at 80. I have an '88 with auto trans. In the two years I ran that combo, I drove from CA to CO twice, and to Moab twice, and to AZ twice, plus trips all over CA, so I had plenty of road miles on it. No question about it....go with the 5.13's.
 
Goatman, hows did the engine like running around 3k? I've got basicly the same engine and do most of my driving around 80 and figured 33 and 4.56 would be better.
 
Weasel said:
Goatman, hows did the engine like running around 3k? I've got basicly the same engine and do most of my driving around 80 and figured 33 and 4.56 would be better.
Click to expand...

The 4.0 doesn't mind rpm at all, it has a pretty short 3.1" stroke and will run 3000 rpm happily all day. I have an '88, so the power isn't as good as a later model HO motor, so I needed the lower gears. If you regularly drive 80 and have an HO you probably have the perfect gear ratio. Also, I was happier with the 4.56's when I ran 33" BFG MT's, when I went to 33" Swamper SSR's I really wanted a 4.88 ratio. The SSR has a slightly bigger diameter (closer to actually being 33") plus they weigh more and are a softer compound. As far as power goes, going from the BFG to the SSR felt like going up a tire size. More info than you asked for, but some reference info for those who are interested.
 
No that's good info. My Parnelli's actually have been running larger then the listed size(31's measured 31.20") and I'm assuming the 33's will run the same. And engine is a non HO 89. I'm just don't want to be over reviing the engine with all the highway driving I do which is 75-85 depending on which state I'm blasting through. How was the gas mileage with 4.56/33's vs. 4.88/33's? I don't know the weights of the PJ's vs. say the BFG's but I think they weight more, so I will keep that in mind.
 
I also have a '97 with AW4 and 4.56's with 34x12.5 tires...I like the onroad combo, because I can run in the mountains in 3rd gear (OD locked out) at the perfect RPM for 60-65 mph...but that's at 9,000 - 12,000 ft. elevation, so we deal with a lot of elevation power loss here. Offroad, I don't think it is deep enough (again at high elevation).

I would never trade up in gear ratio considering the offroad bias of your rig. My perspective on diff gears with the auto for road use is that it primarily shifts around the "dead spot" between OD and 3rd (as long as the gears aren't simply too tall or too low). I didn't like 4.56's with 33's for that reason...I much prefer my larger (and heavier) tires with 4.56's...but I'd take 5.13's in a heartbeat...damn the road issues. You aren't gonna be doing a lot of driving at 80 mph with 37's on that pig, are you :D?

Nay
 
Weasel said:
ahh, nevermind.
Click to expand...

naw, you were right......i was indeed running 5.13's and 35" tires, and it was a perfect gear FOR AN AUTO.....

a few of us tried for a while to obtain the info, and it was finally determined that the aw-4 21 splines have an od ratio of .71 and the 23 spline .75.

either way, that is a nice deep overdrive, and IMHO aw-4 owners should make good use of that and consider numerically higher gear ratios than some of those crummy on-line calculators suggest.

I am now running 5.38's with my 37's, but woould have DEFINITLY gone deeper (trailered rig only) if i could have.....the dana 44 being the limiting factor.
 
21 spline = .705 OD
23 spline = .75 OD

the Renix motors have the deeper OD because they have more low-end and less top-end than the HOs. when I swapped an AW4, I made a point of getting a 23 spline one behind my Renix 4.0 so that I would have that extra hundred or two RPMs on the freeway, and I had already committed to 4.88s and 35s.

bottom line: do the 5.13s
 
Right now I have 4.88s and 35s and it winds up pretty bad on the highway. I would have been really upset if I would have went deeper. The 40 miles to school and back is killing me when I want to make it in 30 min.
 
azxjman said:
Right now I have 4.88s and 35s and it winds up pretty bad on the highway. I would have been really upset if I would have went deeper. The 40 miles to school and back is killing me when I want to make it in 30
min.
Click to expand...

stick or auto?
 
here are some REAL numbers

70 MPH. 34.7" Tires Measured

with .71 (.705) aw-4

4.88 = 2332rpm
5.13 = 2451

with .75 aw-4

4.88 = 2481
5.13 = 2608

pretty bad? I don't think so.
 
I'm running 4.88 and an auto w/ 33 MT/Rs. It's too low for me on the highway and my engine doesn't seem to like to pull more than 2900 rpms. It may be fine, but it gets significantly louder above 3000 rpms so I just back off. I drive over 100 miles a day and used to drive 80+ all the time. Now I think I'm stuck going more like 70-75. Eitehr that or everyone else is driving 85+
 
Last edited:
im new so could some one please explain what the numbers mean in a gear ratio. I know the higher the number the better it will crawl, but what else do they mean, thanks
 
36 TSL's, 4:88's in the Waggy 44's, wishing I had gotten 5:13's. It still shifts around alot on the road. My vote is for the 5:13's FWIW.

MIke
 
scottsxj said:
im new so could some one please explain what the numbers mean in a gear ratio. I know the higher the number the better it will crawl, but what else do they mean, thanks
Click to expand...
It's a ratio of pinion revolutions to ring gear revolutions.

e.g. 5.13:1 = pinion rotates 5.13 times to the ring gear completing one revolution.

HTH, Dan
 
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