Thanks for the input. Since I'm still researching all opinions are welcomeEverybody always says 5.29s are the way to go for anything bigger than a 35" tire.
You said you're at about 3000 RPMs at 80mph with 36" tires and 4.88 gears. Wouldn't 5.29s lower your RPMs at the same speed?
About strength, I was reading a thread where folks recommended letting the axle shafts be the weak point, or the "fuse". Get your R&P cryo treated, chromoly Birfs and use the stock axle shafts. That way if something goes, it won't be the expensive Birfs or the hard-to-replace R&P. Thoughts about that?
And I also really should have my truck checked out. The previous owner says he THINKS the truck was re-geared but he never confirmed with the previous owners. I bought the truck with 35s and a small lift already on it. At 75mph I'm well under 3000 RPMs.
I would need to drive a stock truck to see if there's actually a difference. Or maybe another truck with 35s and stock gears to see if it's similar. My truck is not an extreme crawler by any means but I do plan on spending a lot of time in the rocks. And I also drive 1-3 hrs on the freeway to get to the rocks, hence my dilemma
A few thoughts...
As far as gears are concerned, I would go 5.29's and not look back, I run 345x75x16's and drive mine on the street quite a bit, drove it 500 miles one way to Rausch Creek last year... And I've has no problems, I don't do 80 on the highway, but who with 37's and a big heavy truck does that anyway...
The ring gears are weaker the deeper in the gears you go.... But honestly, if you sheer a ring and pinion, it's either not set up correctly, or you're doing something you shouldn't (like beating on it in reverse up a hill with the front locked)
I run longs and before I got them I'd break birfs like it was my job, and you are correct with the "fuse" or weak link being moved, but I think that the drive flanges are more of a concern than the ring and pinion...
I plan to upgrade my hub studs and use the drive flange as the fuse, it's easy and cheap to fix and replace..
I'm in no way easy on my truck, and I've broken a lot of stuff, but the ring and pinion are not really a concern of mine, I wouldn't let that sway you away from 5.29's...
Which brings me to your "mystery gears" the easiest way to see what gears you have is to remove your rear drive shaft from your diff, lock your rear, Jack up the rear so both tires are off the ground, mark the top of the tire, turn the pinion by hand until the tire completes one revolution, count the amount of rotations of the pinion and that is your ratio...
