31X10.5X15 Vs. 33x10.5X15 and gearing

[trokedawg]

Currently running 31X10.50 BFG AT's and considering upgrading to 33X10.15 once I install my SS 1.2 lift. Curious to know about power/mileage/breaking power loss.

Unfortunately I had the 15" wheels and 3.9 gears from the factory upgrading from stock to the 31's proved to be not very noticeable. If I moved to the 33's would it be significant? I'd most likely go with BFG AT's, I've seen them for $149 and my current set has served me well.

I do plan on undertaking a +/- 15,000 mile roadtrip in the fall with fairly minimal off-roading, I'm mostly concerned about the performance in snow and on fire roads with the occasional tough trail thrown in.

Also, With regards to running 33's does anyone have any experience with regearing?? I guess 4.88 would be optimal. This would be well outside my level of mechanical knowledge but any estimates what it would cost to get 4.88's and a locker thrown in the rear?

 

[Pikeman]

33x10.50 is a preferred tire for the Taco so would assume it is a good choice for our 4Runner. As for the gearing I am going through the same debate. Going to a 33" tire you will notice some power and mileage loss. If your truck is mainly highway with minimal off-roading then I would recommend 4.56 gears since this will give you almost same final ratio as you currently have. 4.88 gears will give you slightly lower gears which will end up with about a 300rpm higher at freeway speeds. The trade off is you will end up with better torque for any off roading. Cost of parts are the same no matter what gear ratio and should be from 170-200 each axle for gears, plus labor, if you think you might want to do a locker do it at the same time as the re-gear so you only have to pay the one labor charge. Labor charge will vary from shop to shop but there will be a difference if you are able to pull your third members out and take them to the shop instead of having the shop do that part of the labor by driving your truck in.