I have a 06 fx4 with 40in tire looking to do a gear swap any one done this? 488s or 513s

 

There's a lot of people here that done a gear swap. Some will recommend 4.56 or 4.88s anything bigger then that you might lose a lot of top end and fuel mileage. But since you got a 4x4 it could cost around 1100-1800 to do the swap. But I would go with the 4.56. Hope this helps and someone here shortly give you more advice.

 

For a 40" tire I would go 4.88, I have 35" tires and I'm gonna do 4.56, however there is a guy on here that said he had 37" tires and said his 4.56 was too much gear but he may have just been a baby. I definitely wouldn't go 5.13 though.

 

4.88