Gears, Gears, Gears

[CA-RJ]

We just returned from a week long trip to Utah. To say the 4Runner can't get up long grades is an understatement. It really struggled. I'd start at the bottom at 70, get a third of the way up and shift to 4th and hold that to 55 ish and then hit 3rd to maintain 50. It wasn't always that bad, but any hill required at least 4th and the 4Runner couldn't get out of it's own way. All the while, the water temperature is climbing because it's hot, the a/c is on and the engine is working so hard to try and climb these grades.

I think a regearing is in order. Even the wife thinks so. What do I run? 4.56's or 4.88's? I have a 5 speed and run 285/75-16's (and will probably always run this size). I'm not so worried about crawl ratio. I do a couple of "harder" trails a year (which I have done with my stock 4.10's). I plan on buying a trailer to haul our camping gear in the future as well.

So, what say you?

 

[bmh]

4.88, unless you plan on upping the tire size later. Then 5.29, re-gear once and save money

 

[Dave Bennett]

This is what I used for calculating gears for 33's

Axle Gearing: How to choose the ratio.

(4000x0.75) x 33.5 x 1.284
_____________________

80 x 336

= 4.88

 

[Hilux_Max]

Ok,

I'll try out that forumula for myself......


1400 x 33 = 46,200

60 x 336 = 20,160

46,200/20,160 = 2.292

2.292 * 1.295 = 2.97


Thats not right.......2.92 is way below my 3.73: 1 that is standard......

my peak torque is at 1400rpm.....what went wrong?
tyre size equals 33"
overdrive = .705
ideal cruising speed = 60mph

can anybody help me out, or doesnt think equate with diesels?

 

[Rexsname]

HIJACK-- Does anyone know the 1st gear ratio in the Toyota automatic transmission found in a 2001 Tacoma? I'd like to figure out my crawl ratio.--
HIJACK OFF


REX

 

[deadbeat son]

Ok,

I'll try out that forumula for myself......


1400 x 33 = 46,200

60 x 336 = 20,160

46,200/20,160 = 2.292

2.292 * 1.295 = 2.97


Thats not right.......2.92 is way below my 3.73: 1 that is standard......

my peak torque is at 1400rpm.....what went wrong?
tyre size equals 33"
overdrive = .705
ideal cruising speed = 60mph

can anybody help me out, or doesnt think equate with diesels?

Great post Dave. As the variables are considered, my formula appears to only work with a modern DOHC V6

So, it will be fun to consider other options of calculating the result.

Per multiple posts in the linked thread, it looks like this formula doesn't work for your engine.