37's and axle ratio

[smoky]

Hello all. I currently have 35" ridge grapplers on 20x10 -18 fuel wheels on my 2023 ZR2 Silverado. It's lifted a total of 5" and can adjust to 6-6.5 according to my custom shop. I'm interested in changing my tire aspect ratio and I am debating between 37" tires on my current wheels or switching to 17x9 wheels and staying with a 35" tire. My question is if I go with the 37" tires on my 20" wheels, is an axle gear ratio change required (and available) and will the mpg totally tank (mpg currently runs anywhere from 13-16)? One other option is to go with 17" wheels with 37" tires to keep overall tire weight about the same as it is now. Any comments and suggestions are welcomed!

Thanks!

 

[Nmass94]

3.68 would be the ratio you want to achieve to get it close to stock ratio (assuming 32.5" tire). I believe 3.73 would be the closest stock ratio that'd achieve that.
However I swear I read somewhere that you can regear these as the ring gear is welded to the carrier. If that's true a regear would be a pain in the ass.
A regear is never required- you'll have enough power to get going. But everything will suffer.
A regear is always the best option however. Last time I regeared a truck for 35s I was able to get within 1-2mpg of stock economy, plus I still had good acceleration.


In regards to your tire question- big tires/ small wheels is typically lighter than big wheels/ small tires.
However depending on the quality of the wheel that may not always be the case, or as big a difference at least, with offroad truck sized tires- don't quote me on that.
I'm always a fan of more rubber less metal, so I'm partial to 17s