Gearing question for GX460 (1 Viewer)

[Nealo]

Hi y’all. I just picked up a GX460. I bought a GX470 back in 2016 that I sold at the height of the pandemic, then picked up 2.5 Tundra. Getting back to my roots and looking to mod the GX460, very slowly I might add. I searched but couldn’t find much information regarding re-gearing with 33’s.

I’m looking to add oversized tires to the stock wheels, and I’ve seen that 275/70/18 fit with the BMC, bumper trim, etc. I probably wouldn’t have thought about a regear but I have a pending (non-refundable) deposit at a gear shop, that I need to use. Long story short, I have a JKU that I was going to regear but now I’m just going to swap in a pro rock set.

Sorry for the long backstory but would 4.88’s be too deep with 275/70/18 (approx 33.1 inches)? If I didn’t have plans in the distant future to go to 35’s eventually, I’d get the 4.56’s and call it a day. I don’t want to have to regear again, or regret the 4.56’s when I finally slap on the 35’s.

Thank you.

 

[JDUB fab]

I don’t have a link for you but I know there are gearing calculators online, you input a bunch of info on transmission rations, tire size and such, it then can speculate on different rpm at a given speed. The goal is to bring it back to stock rpm let’s say at 70mph.
I will say from my own experience, I went from 265/70/17 to a 35” tire and haven’t regeared yet. I certainly want and am planning on re gearing but for the time being, even on 35s it’s not so bad. I think I’m at like 1500 rpm at 70mph on a flat road, which is definitly low. But I am surprised by how well it drives without gears at the moment. I do have a pedal commander, which helps keep its pep.
I’d be Intrested to hear what ratio you end up going with. I’d say prob 4.88s but I’d need to do the calculations to see. In the Tacoma world people go up to 5.29s for 35s but obviously slightly different parameters.
Good luck!

 

[Jstawgn]

4.56 would be better if you are fairly light and do a lot of highway driving.
Heavy with a lot of wind resistance then 4.88 would be better.

Most 35 are about 34.5" tall.
OEM tire are 30.5" tall.
Stock gearing is 3.91
34.5/30.5X3.91=4.45 to bring it back to stock.

 

[r2m]

This is what I used: Gears: Just Differentials: 4:56 with lockers front and rear: Nitro Gear Package - https://www.justdifferentials.com/Toyota-Gear-Package-p/gpfjcruiserxxx-3.htm
with these tires: LT285/75R17 BF Goodrich BFG M/T KM2 which equate to 33.8" O.D. tire.
For what I'm running and how loaded down my rig is, I've never had an issues with it "hunting" for gears on long grades like the Grapevine, and Cajon Pass. Being from San Diego, you know the highways I'm talking about.
In short you should be fine with a 4:56 gearing.
If you want to know more of what I have with that gearing, my build thread is here: Builds - R²M 2013 GX 460 Overland Build - https://forum.ih8mud.com/threads/r-m-2013-gx-460-overland-build.1104719/

 

[Nealo]

I had 5.29’s on smallish 35’s with my old 5.7 Tundra but it still felt fine while going 80. 4.56 sounds like the way to go with the GX, thanks guys. I’ll be on the long grades down here in SoCal for sure as this will be our primary road trip vehicle.

 

[BigSwede]

I have 35s and 4.88s and I am about 10% overgeared, which is fine with all the extra weight of tires and armor etc. But for 33s I would think 4.56 would be better, and it wouldn't be under geared even with 35s.

 

[URJ150L]

I have 4.88s and am running 32s… 70 is a tad over 2000 rpms. If you want to eventually go for 35s, I would go for the 4.88s, which I think is as high as you can go with 8.2 mini axle

Here’s a calculator you can play with: Spicer Transmission Ratio RPM Calculator - https://spicerparts.com/calculators/transmission-ratio-rpm-calculator