Bigger tires any issues I should be aware of? (1 Viewer)

[r2m]

When is a regear needed? Is there a certain threshold in which you need one. Or once you are out of spec you should get one?

Re-gearing your diffs is a personal choice. You can run 40" tires and not have to regear, but your engine and trans will be under terrible strain.
People run 35" tires all the time without a regear.
When I added the front and rear diff lockers, since they were already taken apart, I went ahead and re-geared. At the time I was running 285/75R17 which equate out to 33.9" diameter tire. I'm now running 315/70R17's (35") and the re-gearing helps a lot running both size tires.
My best guess would be once you're getting into the 33"-34" plus size tires, you may want to consider a re-gear. It's not a must, but with larger tires you'll feel a lack of power going over long grades, pulling trailers or even just overloading your rig for that family weekend outing.
With a re-gear, it's also a little easier on the drive train. Your engine and trans aren't working as hard.

 

[re_guderian]

For sure! But the hitches do play a part in the whole being that the different class hitches are vastly different in comparison regarding their under-body space requirements. I'm in agreeance with everyone here, but there are variables that some seem to be forgetting to point out. We all don't have the same options underneath.

Not really. You can run with no hitch at all and you're not getting a 33" spare in there. Probably not even a 32". Just roll under and look with a tape measure. Use a grinder, KDSS spacers, whatever you want, but a 33" just isn't going to fit (fore/aft being the limiting dimension). And if you're only running 31.5's, or maybe 32's, then just roll with the OEM spare. It won't immediately (or even in the short term) shred your center diff, the Torsen center diff can tolerate those smaller mis-matches just fine, unlike the viscous coupling type center diffs on Subarus, early Toyotas, etc. Or, spend minimum $1,000 (JW, cheap hitch mounts) up to $3,000 (for a rear bumper) and make your rig possibly not fit in the garage, lose departure angles, and incur crazy access issues of having to open a swing out every time you want to open the barn door. Or chuck the spare in the back, and take up 25% of the usable space, and deal with strapping/securing/smell issues. It's another limitation of the slightly smaller platform. For comparison, I could get a 295/75/16 spare under my 100 series LC. With a bit of effort. And getting it back out wasn't easy, but hey, it was there. And we struggle with 31.5" spares...

 

[URJ150L]

With 33s you might want to start thinking about re-gear… with 35s you might want to seriously start thinking about it.

Personally, I re-geared right away… 6th was so weak it was useless… couldn’t even hold cruise without shifting all over the place.

 

[URJ150L]

My experience with a spare and spacers has been this:

265/70/17 with class 3 receiver and no spacers - fit, stuffed up in there, wrestling match to get in

265/70/17 with class 3 receiver and spacers - fits with room to spare, cranks right in

285/70/17 with class 3 receiver and spacers - doesn’t fit, receiver is interfering, might fit with no receiver but it would be close and would be stuffed up in there at best

 

[Washingtontaco]

With 33s you might want to start thinking about re-gear… with 35s you might want to seriously start thinking about it.

Personally, I re-geared right away… 6th was so weak it was useless… couldn’t even hold cruise without shifting all over the place.

33's definitely regear.