That's the crayon eating, nose picking math I like. Breaking it down Barney style

 

x2 on the lol

 

I am running the same combo on my current build and I am going with 33's and that's with chromos in both. Yes I could run 35's but that is pushing the limits more than I want.

 

If I go 37s I am switching to regular steel wheels. That will save some weight and make them not much heavier then the wheels and tires are now. It will be fine for a while, if I break a shaft I carry spares and everything is never seized so I'm not worried. I have a friend that goes with me wheeling with a yj with a welded d35 and 35s also it's stick. I am not too wpried about it. It depends on how you wheel.

 

It's not just about weight it's more about the leverage of the tire due to it's diameter. I'd worry about that 4:88 gear set before I'd worry about shafts, well maybe not with garbage cv shafts. But case deflection can be a ***** even with a light foot. $250 for gears and install kit plus $250 for installation might suck.

 

My plans to run 37s on the HPD30 are 30 spline RCVs (or a super30 kit if funds don't allow RCVs), Arctec truss w/C gussets, and 4.56 gears cuz of the stronger pinion over 4.88s. It might be slightly underpowered, but that will keep the breakage down. And it can't be any worse than the 3.55s and 33s that I have now. I don't mind the 3.55s and 33s and don't feel the need for more power. When I need more torque to the wheels offroad then I use 4LOW.

I don't know enough about the 29 spline 8.25 to comment on its strength. Seems like a truss and chromo shafts would be fine for 37s. I'm either gonna stick with my 8.25 or swap an 8.8 for 37s. I still have to learn more to decide which is a better route.

 

37's are pushing the limits on that combo, regardless of all the money you spend beefing it up....period.


As for the 29 spline 8.25 rear, the weakness is in the small pinion bearings.

 

Pick up an explorer 8.8 with 3.55 gears and a swap kit. You'll be in the hole $300 at the most.

 

Good luck man lol

With all that money you're gonna spend polishing those axles, you could buy an already built set of 3/4 tons or even tons that will hold the 37s a lot better.

 

Yah I could easy spend the same or less money and run tons, but to get the same amount of ground clearance as a D30 on 37s you would need to run 44s? under those big *** axles.

Dynatrac portals are the ultimate axle in my mind cuz they afford you the most ground clearance and are stupid strong, but I wouldn't trust the unibody for a second to hold up to the added stress from portals.

I don't rock crawl. Just trails, mud, and beach so I think I can make the D30 survive 37s. The pinion is def the weak link b/c it is the only part that can't really be made stronger besides changing gear ratio.

Anyhow I see the value in tons, but for my build I don't see that being the direction I wish to go in.

 

D30/Chrysler 8.25, lockers 4.56 gear, have been running 35's since 2006.