285's + 3.73 gears = Hows driving in the mtn's

Timberrr · 11-07-2009, 09:33 AM

For those of you who drive in the mtns with an auto and 285's , what are your thoughts?

To Gear or not to GEAR? That is the question.

From My previous life as a Jeeper it was a must.

31's need 3.73
32's need 4.11
33's need 4.56
35's need 4.88
37's need 5.13
etc. etc.

What's funny is from the Searching I've done seems lke many people don't bother til they step up to 35's.
What do the Colorado Peeps thnk.

cruzrman · 11-07-2009, 09:48 AM

Just leave it in 4th and you'll be fine. It will occasionally upshift to 3rd on steep inclines, but that's perfectly normal.
cruzrman

ocr14a · 11-08-2009, 08:24 AM

I got nothin (will probably remain stock for a while), but I am curious. So, just checking in here to get the updates if anyone else offers their thoughts.

Chris Sandstorm FJ · 11-17-2009, 12:15 AM

The FJC seems to be a bit different, not sure if it is also do to engine power and torque..But it seems to be fine with 33s and 3.73. I believe most only go to 4.11s when they add 35s on the FJC..

I would do a search forum wide and use that as a guide. My coments could be off.

ajstoy · 11-17-2009, 01:47 AM

im not in the mnts, but i added the 35's, and 7" of lift, not to mention stereo, bumpers, sliders, and MUCH more. had no issues, with the exception of when i had the cruise set, it would down **** often, when i regeard, the problem was solved. also, ive got a cai, and chip, so that didnt hurt. id venture to guess your ok,

Brock · 11-17-2009, 06:50 AM

I have Nitto 295s...so slightly larger than what you are asking...but have auto tranny with the 3.73 and drive in mountains a bunch.

On flat land not very noticeable actually as the torque converter in AT does good job of locking up and gettting you going. In mountains it loses its legs especially if you have 700 pounds of steel bolted on her with front bumper and 12k winch, rear bumper, rear swingout, full budbuilt skids, rock sliders, rear diff armor, shock armor, LCA armor, new roof rack...plus my fat ass. Then add your gear for camping, eating, clothes and recovery gear and you have nearly a 1000 lb load. Even then she does good but not fast and takes a lot more gas to get her up and down.

When I notice it a lot is on rolling hills or slight inclines when using cruise control...it is always downshifting like I want to race or pass someone...and then has to go way above the set speed limit in cruise.....before she exhales and relaxes for next slight rise.

I am going to 4.56.......maybe next year to get back some oomph at low speeds while crawling and to keep my tranny from shifting so much in hills and mountains.

That being said I drove to Ouray through Rockies without much problem but when I was going through divide she was working hard....alot was altitude but part was gearing as well.

4.11 will get you slightly less than back to stock I think....and 4.56 will get you a little more than stock...well for me. I think 4.11 would get you back to where your vehicle was with the 265 tires which is good enough for most.