95 FZJ80 Ring & Pinion Swap to 5.29

[Pitch]

Another vote for 4.88's. My 3FE runs 5.29's and 35's at 7k feet around my home. 70mph is about 2800 rpm. Even at this elevation, I would not run that gearing on my 1FZE Cruiser.

Spartan the rear, but not in the front end unless you have locking hubs. And even then, do not put an auto locker up front if you ever have any chance of driving in snow or ice. A locked front end and steering do not go well on anything other than slow speed affairs.

 

[jfz80]

. As far as freeway driving goes, who cares if you're at 2800 vs 3100 at 75? The 80 gets horrible gas mileage what's a couple of more bucks in gas.

Also i would pull the 3rds and take them somewhere reputable. Most good shops will do the labor for $250 or less per 3rd (I'm in SoCal).

For me its not gas mileage as much (though a pertinant concern) as not wanting to hear the exhaust screaming down the highway (also on replace list) for hours on end.

Shops quotes here have been 350 and 400 per diff. Sounds like west coast is cheaper for once though id likely send mine out to ZUK; ken francisco in chandler AZ.

 

[alia176]

I second Zuk for his R&P setups if you ship him the 3rd members in a Home Depot bucket. Gear Install Harrop

 

[nukegoat]

Rear is harder than front to diy

 

[916rockcrusher]

I can't decide what ratio to go with either and I need to pull the trigger soon. Stock tires with stock gears wasn't low enough for me when driving from Sacramento over the summit and I don't even have bumpers or sliders yet. With stock tires and 4.10s it would shift in and out of OD constantly and lock and unlock the TC every 1/4 mile on milder grades. I have 315s now and it's not horrible in 3rd but I don't like taxing my trans like that. Are 5.29s with 315s enough to go 65 up a steep grade above 5k feet without kicking down out of OD or having the TC unlock? If 5.29 won't accomplish this I'll probably go 4.88 for the cruising speed improvement since I have to deal with downshifts any way. I'm ok with either Offroad because of the auto trans.

No one has mentioned this but going too low with auto trans can overpower your brakes when crawling. Experienced this on another rig it sucked having to throw it in neutral on steep descents and going down rock faces to go slow enough.

I'd like to know from guys running 4.88 with 315 tires if there was any improvement in power over stock tire size and stock gears pulling hills at higher altitude. I know the final drive ratio is slightly lower at 4.88 with 315s but does the lower ratio under compensate for increased tire weight and wind drag compared to stock?

I've never geared a streetable rig before and it's seeming hard to have my cake and eat it too.

 

[916rockcrusher]

Also for reference I'd really like to know how many MPH off the spedo is at true 65mph on a gps device with 5.29 and 4.88

 

[alia176]

Also for reference I'd really like to know how many MPH off the spedo is at true 65mph on a gps device with 5.29 and 4.88

use a tire/gear ratio calc on the 'net for the #s you're seeking. Since you go up/over the passes, I vote for 5.29s and 315s, especially with the anemic '91 engine. You know you'll want to go to 37s in the future. Granted, your speed will suck when you're near sea level and want to haul the mail but them are the trade offs!