Axle replacemnt with larger tires?

[mdgrmt]

If i upgrade to 285's on my 4runner, will a new axle be needed to keep speed at normal pace

 

[brian2sun]

Axles are not changed to maintain speed. Regearing the diff (or diffs if it's 4x4) will put your power back where it was with smaller tires. I went from a gear ratio of 4.10 with 31" tires to 4.88 with my 33.5s and the power is right about the same. Regearing is not cheap, but IMO it's the single most important performance mod you can do to a lifted truck with oversized tires. There is a ton of info on here and yotatech about regearing. It is not necessary, but it definitely makes the truck better to drive and is healthier for your engine and tranny since bogging it down will reduce their life over the years.