ucfavenger

can anyone elaborate to the strength difference between the 4.88 and 5.13 in regards to the pinion size for a d30?

basically, i am leaning towards the following for my next build phase:

front/rear arb locker
front/rear chromo axle shafts
front evo c pillart gusset
front evo axle sleeve
re-gear

now i am trying to figure out if i want to regear with 4.88's or 5.13's for my auto with 37x13.5's. I am just concerned that the 5.13's will be too high of a gearing (too small pinion teeth) and i will be susceptible to an explosion in my differential. therefore, i am leaning toward 4.88's in an effort to ensure strenght over the full low end power benefits of 5.13's.

i would like to hear everyones thoughts and/or feedback....

thanks!!

ucfavenger

oh yeah...

although upgrading to a d44 or d60 would seem to be a solution, it just inst financially feasable. im pretty set on polishing the dana turdy at this point.

JPop

There is a 2 tooth count difference between the two gear sets on the ring gear. The pinion gear where most of the work is done has the same amount of teeth.

4.88s

Ring Gear Teeth: 39
Pinion Gear Teeth: 8

5.13s

Ring Gear Teeth: 41
Pinion Gear Teeth: 8

That isn't enough of a difference to end up with the wrong gears and with an automatic and 37s the steeper the gear the happier you are going to be.

ucfavenger

wow, really great data.

thanks!!!

RedneckJeep

I guess the basis for your question is the concern for shearing off pinion teeth. I wouldn't give it a second thought with the stock JK engine.....AND a WISE foot on the gas pedal.

slacktide

its not so much the amount of teeth its the size. Once you go past 4.88 with a D44 the weak part of your axle becomes the gears.
4.88 with D44
5.3 with D60
My 2 cents

wayoflife

honestly, i would have agreed with this statement 100% up until moab this year. here is a shot of trail bud's rear 5.13 after making an attempt up an obstacle on metal masher.....



stock jk engine and from what i could tell, not too heavy on the gas. granted, this could have just been a bad ring gear and i'm pretty sure he's getting it warranteed.

ucfavenger

wow! thanks for the pic.

its really a tough call. ie: strength vs performance. i literally change my mind by the week. ha.

thanks for the input everyone.

slacktide

4.88 with 37s gives you better performance than

4.11 with 32s (stock)
also keeps the strength

wayoflife

yeah, that is true but with 37's, your jeep would be big a dog on long hill climbs. with 37's, 5.13's do a pretty good job of giving you stock like performance.