(V8 ZJ) HPD30 on 35s...

[NW-ZJ-SCOTT]

So I have a high pinion dana 30 in my ZJ

It's built with the following

Full case Detroit locker
Nitro alloy shafts
4.56s
Nitro tube sleeves
Inner C gussets
Mini-truss
BTF diff cover

And a full WJ knuckle swap

Current wheel/tire setup
35" kevlars on 15x8 steelies


I'm on my 3rd ring and pinion, and I just scored some 15x8 raceline monsters.. I'm considering selling my 35s and stepping down to 33s.. Clearly the easier answer is "build a 44" but I'm pretty deep into this 30 and I really can't justify the price of "big-boy" axles right now..

Even with 2low I still know the limits of the dana 30's tiny pinion and somehow find a way to "cross the line"

With all of this accounted for.. I could buy new 33s.. But is it worth it? (Hassle.. Not price)

 

[yossarian19]

Worth the hassle? Of stepping down to 33s?
Yes.
You can sell your 35s to recoup some of the cost of 33s. Plus...
Think how long ago you broke your first R&P. That amount of time, divided by three. That's how long you can expect your gear set to last. How much does it cost in time, energy & cash to fix a R&P? If you stop breaking them, you have made an investment that pays off in that $$ amount every xx months.
There is also the hard-to-quantify reduction in wear & tear on your Jeep by reducing the rotating mass.

 

[NW-ZJ-SCOTT]

That's been my thought... But I fear 33s aren't enough of a difference and I would hate to step down if it's barely a difference

 

[souske]

have you considered getting the next set cryo treated?

 

[yossarian19]

Well, I've never heard of guys blowing up the R&P on 33s. Not saying you couldn't / wouldn't, just that it's a lot more likely to hold.
It's about a 6 lb weight difference per tire, or 12 percent (going by BFG AT specs). For the same tire speed (wheel spin), that's a fair bit less load into the R&P when it catches traction.
In the KM2, it's only a 3 lb difference.
'Course, that 1" less radius is going to have an affect on forces to the R&P too...
I'm too lazy to figure out the math right now but my hunch is that you'd save gears if you went down to 33s.

 

[blondejoncherokee]

third R&P? so its so strong you now have a new weak link the R&P. theres nothing else you can do to that 30 to fix that part other than go down in tire size so do that now. and don't get happy with the throttle pedal.

Short run :
go down to 33s.

long run:
build a better front end, hp44, hp60, 609, currie 8.8 front, there are lots of options.


I recouped like 2000$+ on my 30 parting it out. yours is a lot like mine, so figure around 2000$+(parting out that 30 will bring more than selling it whole)

figure around 1000$ for a geared and locked hp44 on pirate. then add 1000$ to get it under your rig for brackets, lockouts, brakes, etc etc . add 500$ for misc.

 

[NW-ZJ-SCOTT]

have you considered getting the next set cryo treated?

Yes.. But that's as far as I've gotten.. "Considered"

third R&P? so its so strong you now have a new weak link the R&P. theres nothing else you can do to that 30 to fix that part other than go down in tire size so do that now. and don't get happy with the throttle pedal.

Short run :
go down to 33s.

long run:
build a better front end, hp44, hp60, 609, currie 8.8 front, there are lots of options.


I recouped like 2000$+ on my 30 parting it out. yours is a lot like mine, so figure around 2000$+(parting out that 30 will bring more than selling it whole)

figure around 1000$ for a geared and locked hp44 on pirate. then add 1000$ to get it under your rig for brackets, lockouts, brakes, etc etc . add 500$ for misc.

Yea.. I go back and forth.. I want to go bigger axles and 37s sooner or later.. But I don't see it in the cards for this year.. As I plan to DD the jeep 75% of the year..

I think Cryo treating the new ring and pinion (awaiting install) and stepping down to 33s will really do the trick for awhile

 

[ruger81]

You need to make the weak link somewhere else. what about adding locking hubs or switching out the Detroit for a selectable locker? sell the Detroit. What yoke are you running? maybe switch to strap yoke instead of a u bolt style.
My thought is if you can create a weak link(fuse) somewhere easier/ cheaper than the ring and pinion it would be better to deal with.
I noticed a drop in breakage when i went selectable in the front.