What does...

[subzali]

90:1 - 96:1 gear reduction feel like?

I've seen upwards of 130:1 and just wondering how high do you need to go? Stock FJ40 is about 25:1-28:1 depending on year, so what's the difference between 3x as slow and 4x+ as slow? What kind of obstacles (take Moab for example, or others) would need something more than a 90:1 ratio?

 

[Uncle Ben]

90:1 - 96:1 gear reduction feel like?

I've seen upwards of 130:1 and just wondering how high do you need to go? Stock FJ40 is about 25:1-28:1 depending on year, so what's the difference between 3x as slow and 4x+ as slow? What kind of obstacles (take Moab for example, or others) would need something more than a 90:1 ratio?

That is the million dollar question my friend! Silly low often helps more for control and descending big rocks. Climbing takes a gear that crawls slow enough for control but also carries enough margin of acceleration for a bump if needed. Just the addition of an SM 420 to your mix would yield 66.65! Which is pretty low. Add 4:56 gears and now your playing with 73.94:1! 4:88's = 79.13!

The fun fact is 1st gear in a 420 in high range with 4:11's is 28.98:1 which is lower than what you have now in low range!

Example of stupid low obstacles in Moab would be Can Opener, Rocker Knocker, No Name and Yellow Hill on Pritchett, Rock Chucker and Mirror Gulch on Metal Masher, Pot Holes,Several challenges on Tie Rod Flats, Golden Crack (and obstacles around it) and Body Snatcher on Golden Spike, etc.... Other obstacles are just as tough but often can't be crawled due to physics (lifting a vehicle weight straight up without full traction).

 

[subzali]

Well I'm thinking H41 (4.925) or H55F (4.84), Orion 4:1, and 4:56 or 4:88 diffs, which would yield around 90:1.

 

[Uncle Ben]

Well I'm thinking H41 (4.925) or H55F (4.84), Orion 4:1, and 4:56 or 4:88 diffs, which would yield around 90:1.

Awesome combo! remember 4.88's are a PITA to get C-clips back on in a semi float! .....and the higher the number the weaker the pinion strength!

 

[nuclearlemon]

Well I'm thinking H41 (4.925) or H55F (4.84), Orion 4:1, and 4:56 or 4:88 diffs, which would yield around 90:1.

it'll make driving to the trailhead suck. stick with 4.10s and the orion.

 

[Rzeppa]

I REALLY liked the 5:1 of the H55F, about the same as the H41 I put into my 76 but haven't driven yet. I'd say the Orion is probably the best way to go, but they sure are expensive. Thing I don't like about SM420/465 is you're basically now a 3 speed tranny, never use granny gear on the road. Plus I hate the way they shift, Toyota trannies are so much smoother.

I've seen a number of instances where somebody with too-low gears couldn't make it because they didn't have enough mo and had to back up, put it into a higher gear and try again. The "Ugly" of the Good, the Bad and the Ugly on Steelbender comes to mind. Usually it's where the traction is loose, crumbly, slick, etc.

 

[treerootCO]

If you smell your clutch every time you wheel, you need lower gears. A bigger motor would also be an acceptable answer. The one answer I won't accept is driver experience. It is a pain in the a@@ keeping the engine lugging along without slipping the clutch or beating the piss out of yourself and rig.

 

[treerootCO]

http://www.root45.com/SM465Orion/Gears.htm

save and open in Excel and you can play with the gearing combos. I was too lazy to write the html.

 

[treerootCO]

Come over and you can borrow the 40 as long as you like. Take it wheeling, beat the piss out of it....and yes I am serious

 

[Romer]

If you smell your clutch every time you wheel, you need lower gears. A bigger motor would also be an acceptable answer. The one answer I won't accept is driver experience. It is a pain in the a@@ keeping the engine lugging along without slipping the clutch or beating the piss out of yourself and rig.

Course now that you have an 80 you won't have to worry about the burning clutch smell

 

[RockRunner]

Lower gearing can be a great thing and a handicap. I am running dual cases in my 4runner with 5.29's. When I run the 2.8 Tcase and wheel different areas it takes a little more finesse with the throttle and or clutch. When I use the 4.7 case alone those areas are far more easy to handle and I can control the speed of ascent or descant with the throttle. Also with the 4.7 engaged I can apply the brake without having to use the clutch and worrying about stalling the engine, within reason.

When using both cases I drop down to 223/1 and crawl at 1/3 mph with total control. I can just about apply the brake fully and not stall the motor. This makes finesse crawling feasible and some of the harder trails a lot more fun. Like some of the others mentioned finding the right gear can be a trying experience.

I know this isn't exactly what you are looking at but lower gearing makes wheeling a lot more fun. Some obstacles that were impossible before become possible with lower gearing. Driving to the trail is a little harder with lower gears and the gas mileage does suffer if it is a DD but what you get in return is worth it.

I hope this helps somewhat, or maybe it tickled your mind regarding a dual transfer case ;-)

 

[nuclearlemon]

I hope this helps somewhat, or maybe it tickled your mind regarding a dual transfer case ;-)

this from someone who towed to the trail

problem with an fj40 is lack of room for dual tcases. you end up with a 12" shaft...and that's in male measurements

 

[bigbluefj]

sm420 and 4.88's are nice on the the trial and add the compression of a 350 and it's really nice going down hill ...

 

[RockRunner]

this from someone who towed to the trail

problem with an fj40 is lack of room for dual tcases. you end up with a 12" shaft...and that's in male measurements

I would have driven there but the comfort of my DD is to great. Also I need to know how it handles, it did pretty good. This way I have three options for Moab, most likely I will still trailer it out there, just incase it rolls.

Not to familiar with the 40's would love to have one but $$$$ i do understand the 12"s that is a tough one

 

[wesintl]

Well I'm thinking H41 (4.925) or H55F (4.84), Orion 4:1, and 4:56 or 4:88 diffs, which would yield around 90:1.

I kinda like that combo with 4.11's. As you know blow a pinion and you have to build another diff with 4.88's or have some flown in. It's easy to find a 4.11 chunk and plop it in and move on. for example look at nutleys rig. I still think he's runnin 4.11's

 

[subzali]

What are the guys in 80s running in their diffs with 35s (nakman, Romer, Uncle Ben, etc.)? 4:56 or 4:88? Looking at the H55F, in 5th gear at highway speed on 35s and 4:88s I would be spinning 350 rpms less than I do now, but then if I drop it into 4th for hills then I would spin about 150 rpms higher than I do now to help with engine power (maybe).

 

[Uncle Ben]

What are the guys in 80s running in their diffs with 35s (nakman, Romer, Uncle Ben, etc.)? 4:56 or 4:88? Looking at the H55F, in 5th gear at highway speed on 35s and 4:88s I would be spinning 350 rpms less than I do now, but then if I drop it into 4th for hills then I would spin about 150 rpms higher than I do now to help with engine power (maybe).

4.56's will take it to close to stock gearing with 35's but of course rolling resistance of the 35's vrs the 31's will factor in and kill some responsiveness. I (and most) am running 4.88's in the with 35's. Again remember, 80's don't have c-clips! 80 guys who run 37's or bigger used to do the 5.29's but pinion strength is an issue and the new trend is back to 4.88's or shorter and lower t-case gearing.

 

[subzali]

Right, I'm thinking way future - full floater rear.

 

[AxleIke]

My truck is 90.6. If you'd like, you can drive it at the next meeting (i should be there).

While it is awesome for many CO trails, there are a few types of obstacles where lower would be a whole lot better, and many trails where it is way too low.

Lower would be for rock gardens. You don't need a bunch of speed and power, but you just don't want to have to work the clutch. On 4 runners at abou 215-228:1, it is perfect. You can idle over everything up to about 2 ft boulders, any bigger and you need to give it a little gas.

The other great option is having stock low range for the cruising parts of the trails.

Obviously, this won't work in a 40. If it were me, with a 40, I'd go with a 4speed tcase from one of the vendors. I just can't get enough of the gearing options.

 

[Rzeppa]

While it is awesome for many CO trails, there are a few types of obstacles where lower would be a whole lot better, and many trails where it is way too low.

Lower would be for rock gardens. You don't need a bunch of speed and power, but you just don't want to have to work the clutch. On 4 runners at abou 215-228:1, it is perfect. You can idle over everything up to about 2 ft boulders, any bigger and you need to give it a little gas.

Obviously, this won't work in a 40. If it were me, with a 40, I'd go with a 4speed tcase from one of the vendors. I just can't get enough of the gearing options.

You guys with 22REs and such have to remember that with an F or 2F (or better yet, a 3B or 1HZ) you get 90% of full torque at 1000 RPM, and can lug that big ol' straight six down to less than 500 RPM and still get up the trail.

Al Ostoff (who has a V8J40) rode with me up the Rock Garden of Spring Creek one year and had forgotten how slow these motors can go. It sounds like it's going to stall, then a bit of skinny pedal and it just grunts right through. Neil Quigley had to drive his 40 at Moab last year because of issues with his runner, and he told me how he had almost forgotten how much different driving a 40 is from a runner, as far as technique. They are like tanks, and the extra low grunt of the stock motor reduces the need for lower gears.

No question, lower gears have their place, but with the stock motor you can do a lot you would have more trouble with a motor that didn't have as much low end. Everything's a trade-off though and there are pros and con's to everything from stock to modified and one model type to the next. And as my friend Wayne Smith says, which I tend to agree with, "the farther you get from stock, the more you sacrifice that Toyota Reliability".