Regearing questions? 3FE with 33's

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Fiveo

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After driving 800 road miles this week. (2) Phoenix to Palm Springs (Flat) and (1) Phoenix to Flagstaff (Grades) I'm really need to regear if I want to keep 33's.

On the climbs its a dog!! Today on the flats I was able to hold 75mph at 2400 rpm and still averaged almost 15mpg. If I was to regear to 4.56, how would it affect my climbing power, RPMs at 75mph and MPG. Or is another gear ratio better? I'm looking to make it more highway friendly. Also what would I be looking at:banana: wise, parts and labor? I would have a shop do it all. I wouldn't de dropping the diffs myself.
 
MJADDICTION had a 3FE with 33's/4.88's and LOVED it. Said it was the best combination for a 3FE.
 
Agreed. I did 4.56 gears when I installed ARBs. I run 33x10.50s on the street and 36" Swampers on the trail. It is very driveable with both tires and I also keep my truck in very good tune, but 4.88s would be better IMO. Not sure about 5.29s, but they weren't an option back when I did mine.

FWIW, the speedo is close to my GPS with 33s and 4.56, so it's close to stock gearing. One bump up from that should be golden.
 
FJ-80's came with 31s and 4.11 stock, correct? FJ-62s came with 28s and 4.11. So the heavier FJ-80 got less gearing stock than an FJ-62?

In my FJ-62 I'm currently running tires that measure 31.4" (Nitto 265/75R16 Terra Grapplers) and 4.56 gears and my speedo is dead on. For reference I turn about 2500-2600rpm at 70mph with this setup. For 33s I would want 4.88s, at least for my engine and my driving habits (lots of mountain passes).
 
Actually, FJ80s came stock with 29s.....31s were a factory upgrade size. I read somewhere that the 4.30 diffs were made for that very reason...get gearing back with the factory upsized tires.

So...
4.10 - 29"
4.30 - 31"
4.56 - 33"
4.88 - 35"
5.29 - 37" to get back to stock.....stock sucks with the 3FE so assume a larger tire than you will actually be using.
 
Alkaline- nice post.

What brand of gears do you guys run or recommend? I'm sure factory gears are $$$$.
 
alkaline747trio said:
Actually, FJ80s came stock with 29s.....31s were a factory upgrade size. I read somewhere that the 4.30 diffs were made for that very reason...get gearing back with the factory upsized tires.

So...
4.10 - 29"
4.30 - 31"
4.56 - 33"
4.88 - 35"
5.29 - 37" to get back to stock.....stock sucks with the 3FE so assume a larger tire than you will actually be using.
Click to expand...

There was no option for gearing from Toyota, at least not in the US. It was 4.11s regardless of tire size. I never heard of a 4.30 gear ratio.
 
I dont paln on ever gong any bigger then the 33x12.5 MT I have now. In fact when these tires I have now are done, I 'llbe switching to a 33x10.5 and maybe even an AT instead of MT. I worry about RPM at highway speeds with the 4.88. That is just from what I have read. I have no personal knowledge or even understand on the mechanics of gearing.
 
Do a google search for "rpm calculator" and you'll find a bunch that you can use to calculate your rpms at different mph and gear ratios. A440F's have a .717:1 4th gear and 1:1 3rd gear (according to Mark's site: 80 Series Info). Note that 3rd gear doesn't have a lockup TC so any calculations for 3rd gear should assume some TC slippage (meaning higher actual rpms than what the calculator displays). Unless you have one of Rodney's valve bodies that has 3rd gear TC lockup added in (which is very nice when pulling long hills in 3rd gear).
 
Man that sounds like math....
 
jonheld said:
There was no option for gearing from Toyota, at least not in the US. It was 4.11s regardless of tire size. I never heard of a 4.30 gear ratio.
Click to expand...

My buddy has factory 4.30's in his 96 SR5 4Runner...
 
How are 4.88 going to be RPM wise at 75 MPH with 33's vs 4.56? If I used JT's caculator correctly (not at all sure I am) 4.88 at 75mph will be just a tad over 2600 and 4.56 will be at 2430 RPM. Im at just under 2400 at 75mph with stock gears. 2600 rpm seems a bit steep to me.
 
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gears

This has been done by numerous people with good results. Your RPM's with 4.88 & 33's will be slightly higher than STOCK GEARS & STOCK TIRES. This helps compensate for other factors like added weight rolling mass of tires, and helps compensate for an underpowered vehicle in general. Fuel Economy is just not so good on LC's any way you run them, and lower gears dont necessarily effect economy.


Fiveo said:
How are 4.88 going to be RPM wise at 75 MPH with 33's vs 4.56? If I used JT's caculator correctly (not at all sure I am) 4.88 at 75mph will be just a tad over 2600 and 4.56 will be at 2430 RPM. Im at just under 2400 at 75mph with stock gears. 2600 rpm seems a bit steep to me.
Click to expand...
 
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