Ok so here's the question. What really affects the ability to upgrade tire size on the Jeep?
For example: I'm running stock size (32") Trail Grapplers that weigh 59lbs each and I have stock gears 3.21. Could I run a 35" tire that weighs 60lbs? Is it the weight that is the issue or the size of the tire?

 

More the tire rubbing due to the 6.5" backspace of the stock rims and not enough clearance. You can run 35's with no lift but you will need flat fenders and wheel spacers. Also expect a great loss of power.

 

Its not so much the weight of the tire but the tires diameter that makes gearing necessary.

RK

 

even if you could find 35" that weighed 50 lbs the 3.21 gearing is going to suck power.

 

A lot of people run 35's with the 3.21- me included- it's my DD so it works- I also have a 2.5" lift and aftermarket rims with 4.75" backspace- fits great! Didn't really lose any power but I have a manual. If you want to mud big or crawl you will need more ass tho!

 

I went 35s with 3.21s 6 speed, still started out in 2nd gear. Didn't notice that much powerloss until I was in 4hi, 4lo was decent but hi sucked. I go play at least once a month so having shit for 4hi was bad to go, so I put in 4.88s

 

I had a 2013 with 33's and 3.21's and I was happy until I drove a 14 with 33's and 4.10's and they all of the sudden I realized what I was missing and why others argued with me when I said 33's and 3.21's were fine lol. now I am a believer that anything over 32's should not have 3.21's.

 

I have 3.8 and i agree with ya. I have to note though that i was planning the re-gear "down the road" but an act of budlight infused dipshititus lead to me destroying my front differential in front of my house. Just glad it happened there and not in the middle of the mountains.