5.13 or 5.38 ?

dennisuello · May 11, 2004

5.13 or 5.38?

i have HP ford 60 front (lowest gear available is 5.38) and debating the choice of rear axle. either Corp 14 bolt (lowest gear available is 5.13) or Dana 60 (7.17 lowest gears). will i be happy running 38.5 TSLs with 5.13s? i have 4.0/ax-15/nvg241(4:1) drivetrain. or should i look for dana 60? or 70? or 80?

i will not go bigger in tire size, as it won't in the garage. :yap:

Beezil · May 11, 2004

trail rig only?

dennisuello · May 11, 2004

BrettM · May 11, 2004

if it sees street time, I say go 5.38. Even lower if the front would allow.

i have mine with 4.88s and 33s, and it's perfect. when I put the 35s on next week, I know I'll wish I'd a gone into the 5s. And that is with much lighter, smaller 35 MTRs, not 4 inch bigger, 2 inch wider, heavy bias tires.

Beezil · May 11, 2004

dennisuello said:
nope

whats the fastest you see yourself going on the highway?

Root Moose · May 11, 2004

If'n it was me, I'd be inclined to go with the 5.12/C14B combo just becuase they seem to be cheaper than a D60.

The difference between 5.12 and 5.38 is probably "pissing contest" kinda stuff.

Maybe try to compare the r&p sizes of the 5.12 C14B to the 5.38 D60? My guess is that the C14B might be physically larger - and maybe stronger because of that. Just a wild ass guess though.

r@m

MuddinXJ · May 11, 2004

on my D44 HP axles i plan on running 37" MT/Rs with either 5.13 or 5.38 gears. most likely 5.13 though cause that is best gas mileage for 37" tires.

dennisuello · May 11, 2004

Beezil said:
whats the fastest you see yourself going on the highway?

speed limit (65 around here)

dennisuello · May 11, 2004

Root Moose said:
If'n it was me, I'd be inclined to go with the 5.12/C14B combo just becuase they seem to be cheaper than a D60.

that's true, plus you can find one with detroit locker.

ashmanjeepxj · May 11, 2004

dennisuello said:
5.13 or 5.38?

i have HP ford 60 front (lowest gear available is 5.38) and debating the choice of rear axle. either Corp 14 bolt (lowest gear available is 5.13) or Dana 60 (7.17 lowest gears). will i be happy running 38.5 TSLs with 5.13s? i have 4.0/ax-15/nvg241(4:1) drivetrain. or should i look for dana 60? or 70? or 80?
i will not go bigger in tire size, as it won't in the garage. :yap:

Dont get a d60 rear.

I had a d70 rear, there are two kinds of gears, .5 off set or .625 off set, you want .625 and thats what I had. you can gear it lower then 5.38 but 5.38 is not an option on a d70 your your still stuck with 5.13s. If you had a cvevy LP d60 front you coudl gear a rear d70 lower then 5.13.

The d80 I think is available in 5.38.

Im Giving a friend my d70 with 4.10s he needed and trading for a 14bolt with 3.73s, then Ill swap in 5.13 gears. The 14 bolt has adjustable preload on the carrier baerings and the addition pinnion bearing. I like that. and this one is 67in WMS and my d70 I think was 63in I could use the width.

I only payed $400 for the front d60 gears, rear 14bolt gears, with mini install kits. (shims and hardware but not bearings)

This guy in the Pirate Vendors forum had the best price on gears I found:
http://www.pirate4x4.com/forum/showthread.php?t=232660

Good luck.

Root Moose · May 11, 2004

dennisuello said:
that's true, plus you can find one with detroit locker.

Yep, going price around here seems to be anywhere from $500-$1000CDN with 4.56 and Detroit. Surplus military I think has flooded the market.

r@m

Blatant · May 11, 2004

I ran a similar setup in a YJ (4.0, ax15, 231 with 4:1) and 5.13 gears worked well with 38.5 SX. Not going to notice a substantial difference from 5.13 to 5.38.
dion

strokedwoody · May 11, 2004

Root Moose said:
Yep, going price around here seems to be anywhere from $500-$1000CDN with 4.56 and Detroit. Surplus military I think has flooded the market.

r@m

I've bought several new chevy d60's and 14bolt military axles from Clark military surplus in Nitro WV. The last 14 bolts I bought were $550.....brand new in the crate, 4.56 with a detrioit. It's nice buying new axles with a locker and they come complete(brakes and all). Then you can just regear them, disc brake conversion are pretty cheap and easy on the 14bolt also.

Root Moose · May 11, 2004

Yeah, we have a local place just outside of Carleton Place, Ontario that gets the same stuff on palettes - fairly certain it is ex-US military as Canadian military doesn't sell anything until it is all completely used up (SeaKings anyone?).

Local place has similar prices in metric Canuckles as well, maybe a touch more expensive - at least last time I asked. Guys in the local clubs rag him as being expensive but I think it is a good deal. Get a POS out of a wrecker and then R&R the axle and see how much it costs is what I always tell them.

Too bad 4.56 wasn't deep enough for Dennis - would be VERY cost effective.

r@m

Beezil · May 11, 2004

dennisuello said:
speed limit (65 around here)

in that case I'd probably go with the 5.38's.....

I have them with my 37's, but i don't see the greater side of 50mph anyway, and when I do, I make milk duds in my drivers seat.

if you run your numbers in a calculator, you'll see that there's not too much of a difference between 5.13's and 5.38's anyway....

good luck!

dennisuello · May 11, 2004

Beezil said:
if you run your numbers in a calculator, you'll see that there's not too much of a difference between 5.13's and 5.38's anyway....

with 5.13:

Crawl Ratio: 78.59:1
Forward Movement @750RPM: 1.5823 feet per second
Reverse Crawl Ratio: 86.59:1
Reverse Movement @750RPM: 1.4361 feet per second
Highway Speed @2500RPM: 69.74

with 5.38:

Crawl Ratio: 82.42:1
Forward Movement @750RPM: 1.5088 feet per second
Reverse Crawl Ratio: 90.81:1
Reverse Movement @750RPM: 1.3693 feet per second
Highway Speed @2500RPM: 66.50

Rawbrown · May 12, 2004

The problem with "the Math" and "charts" is that you don't see much compensation for overcoming the rotational mass of the larger meats.

with 38" tires, high speed and good fuel economy are not going to be in your jeeps best interests. you would be putting less strain on the majority of your drivetrain by being able to turn the tires a little easier. so for strength you could either build a D60 or a ford 9". The disadvantage for the 9" is the lower pinion. but it can be built with 35 spline shafts, detroit locker and its relativly light weight. the D60 can be built good and strong with 35 spline CrMo shafts.

lot of options... I would personally go with 5.38's
doesn't cost anymore that the 5.13's...

5.13 or 5.38 ?

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