Sorry, just don't get what shackle reversal accomplishes

[ojaij40]

Hi guy's, read almost all your posts, and enjoy them all, What does shackle reversal improve? Randy

[peesalot]

After running one for some time and watching similar equiped vehicles with no sr I would say nada, leave it shackle forward.

[greenfox]

I would say don't do it!

What are plans for the rig?

crawler, or daily driver.

[ojaij40]

I was just trying to figure out why ANYONE would do it, what does it inprove? Randy

[bkcruiser]

Approch angle, unless ya install one o them caster correction type

[greenfox]

I doesn't improve anything. People say it drives better after they do it but that could be from a lot of reasons. like new bushings and everything has bin tightened up and most of the time they put power steering at the same time.

[ojaij40]

Thanks guy's I just got done installing a complete 4" Downey Pro Desert lift kit with extended shocks and Rubicon shackles and new greasable pins. While I was installing it IO was pondering what would improve by shackle reversal. Randy

[greenfox]

Originally Posted by bkcruiser

Approch angle, unless ya install one o them caster correction type

That's it Bill I'm going to do a 3 link

[vk7ybi]

Theres a nice writeup by Jim C here somewhere about the suspension geometry of the 40 series.. It makes good sense to leave it alone, I always figured the Toyota engineers know more than the average backyarder, and have probably spend more on R&D developing it.. Theres always those that argue SR must be better because Hiluxs and 4Runners are SOA and SR from the factory, but Toyota has had to put measures in place to counteract the effects of doing so..

[vk7ybi]

Here it is.. Explanation re: Factory Shackle Location - Land Cruiser Tech from IH8MUD.com

[theo]

You can improve your approach angle if you use low profile hangers in front. If you climb boulders (or logs or whatever) you get your tires on the rocks before the shackles grind into them and maybe hang you up. (You can drop off steeper stuff too.)

With the shackles on the rear the springs and tires can compress back and up and make the transition onto a rock or other obstacle a little smoother.

But, compressing the axle towards the transfer case could mean shoving your driveshaft right through your transfer case and out the back side unless you take precautions. The changes in length on the driveshaft are smaller with normal geometry.

Shackle reversals on FJs were started by guys that wheel their junk and needed better off road performance. If you don't wheel hard there's no good reason to do it that I can think of.

[D-Cannon]

I had thought that in addition to hard wheeling, the SR improved small bump (at speed) handling. While it is true that the factory set up will move the axle back on big hits, the axle actually moves forward slightly as it begins to travel up. So, on the highway going 55 mph, when you hit a seam or repair on the road, the wheels head forward, into the bump. The factory set up is a little more "bumpy" feeling, compared to a vehicle that is set up with reverse shackles like the later models.

I could be incorrect.

[motoloco]

I dissagree, I have owned a LOT FJ40's, the BEST driving ones have always been SR. If used with a low pro hanger in front your approach is way better, your truck wont want to follow the road near as much (especially with longer than stock shackles), and hard edge bumps are much smoother since your front axle does not have to travel foward (into the bump) to go upward. That said, there is nothing wrong with a forward shackle set up with nice bushings and a reasonable length shackle, they can drive very nice. I believe toyota did it that way simply because the frames are higher at the ends and it was more cost effective than recessing a hole in the frame for a shackle, which is what they would have to do the keep the correct caster at stock height.

[Sputnik40]

I disagree to a certain extent for anything that's going to see some decent trail use. A low profile SR is awesome - those boat anchor versions from AH are pure rock magnets...

The only disadvantage to me on my low profile SR is the front end diving a bit under heavy braking (not that I'd notice if I'd not tried really hard to see if it actually happened as many say it does).

I broke my front frame horn once trying to push a shackle into and up over a rock - didn't stop me - but it ripped the frame pretty good (boxed now). These days - with low profile hangers - most time the extra few inches of clearance gets by an obstacle, or it easily ramps up and over. Course I'm SOA and have my tie rod behind the axle to boot .

If mostly a DD - then there's really no need at all.

[ojaij40]

Thanks guys you all did a great job of answering my question,
Randy

[vk7ybi]

Originally Posted by motoloco

I believe toyota did it that way simply because the frames are higher at the ends and it was more cost effective than recessing a hole in the frame for a shackle, which is what they would have to do the keep the correct caster at stock height.

Hmm? The reason Toyota designed it like they did is outlined in Jim C's article..

[greenfox]

If you want to get into that far!

If you clime up a rock with s/r your axle will walk out from underneath you rig, pulling the drive shaft out and pulling your pinion towards the ground. As far handling on the road the rig will lean more going around corners do to the fixed point on the frame do to the fact that both axles are being pushed back.

[NeverSummer]

I've read all of your posts and read Jim's explaniation on the location of the shakles. My question is does the same that applies to toyota springs apply if you are going to put chevy springs on your rig?

[vk7ybi]

The theory remains same for any brand of spring in the same configuration..

[Sputnik40]

Disagree again - if not just for the sake of debate - I'm running flat (ok almost inverted now) and flipped stock springs. My axle's not doing a whole lot of walking - and it's pulling up that rock more than it is fighting it .

Originally Posted by greenfox

If you want to get into that far!

If you clime up a rock with s/r your axle will walk out from underneath you rig, pulling the drive shaft out and pulling your pinion towards the ground. As far handling on the road the rig will lean more going around corners do to the fixed point on the frame do to the fact that both axles are being pushed back.

[haystax]

SR by itself won't gain you much, maybe a little better ride quality but you're not going to build a "rock crawler" by simply moving the shackle attachment points.

If done as part of a spring over or power steering or frame strengthening mod then you start to see small tweaks add up into a much more comfortable and better handling package. I know there is a night and day difference for the good after I did all of the above mods at the same time compared to a stock rig. But on it's own you don't get much done and you still need longer brake lines, longer travel driveline etc..

[ojaij40]

Thanks again HAYSTAX, and all others, I knew it must do something, but wasn't obvious Randy

[woooody]

It seems like every few years this comes up, and everyone points to Jim's article as the end all be all.

"Toyota designed it that way, so it must be right"

If that is the case, please explain 1979 - 1985 Toyota Hi lux suspension.

Why would the Toyota Engineers ABANDON front shackles of the Land Cruiser when they designed the Hi-Lux?

I've had SR and PS for 9 years now. It still works, still doesn't wander, still has a better approach angle than a front shackle configuration. I'm using 2 1/2" OME springs. I have never bottomed the drive shaft into the xfer case. I've driven my 40 at 80+ MPH with no problems. I've rockcrawled all over the sierras.

If you don't want to do a Shackle Reversal, fine. But please don't try to convince me that SR is worse than shackle forward.

[peesalot]

no convincing. I to am very pleased with my sr. I do however understand and agree that the better performing link type suspension uses a fixed rear point, so as to correlate that into a leaf spring it would follow that the leaf be fixed at rear end of leaf. Why switch it around for rear axle ???? thats what gets me is everybody debates the sr or no sr issue with blinders about the fact that the rear axle is set up shackle back. Bottom line is that the difference is minimal and you should build what suites you and your ideas.

[haystax]

Originally Posted by woooody

It seems like every few years this comes up, and everyone points to Jim's article as the end all be all.

"Toyota designed it that way, so it must be right"

If that is the case, please explain 1979 - 1985 Toyota Hi lux suspension.

Why would the Toyota Engineers ABANDON front shackles of the Land Cruiser when they designed the Hi-Lux?

I've had SR and PS for 9 years now. It still works, still doesn't wander, still has a better approach angle than a front shackle configuration. I'm using 2 1/2" OME springs. I have never bottomed the drive shaft into the xfer case. I've driven my 40 at 80+ MPH with no problems. I've rockcrawled all over the sierras.

If you don't want to do a Shackle Reversal, fine. But please don't try to convince me that SR is worse than shackle forward.

Exactly - it was part of the re-design of your vehicle and contributed to the ability when combined with other probably more important and gainful mods. In the end you have a better setup than stock - but to leave it out of a front end build up process doesn't make sense either because there are some true benefits IMO

[vk7ybi]

Originally Posted by woooody

It seems like every few years this comes up, and everyone points to Jim's article as the end all be all.

"Toyota designed it that way, so it must be right"

If that is the case, please explain 1979 - 1985 Toyota Hi lux suspension.

Why would the Toyota Engineers ABANDON front shackles of the Land Cruiser when they designed the Hi-Lux?

Ok, so why didnt they ABANDON the design in the 60 and 70 series LandCruiser? Why does Nissan and other competitive manufacturers use the same design?

[woooody]

Originally Posted by vk7ybi

Ok, so why didnt they ABANDON the design in the 60 and 70 series LandCruiser? Why does Nissan and other competitive manufacturers use the same design?

Re - 60 - 70 -- Couldn't tell you. Could it be that they just modified existing FJ40, FJ50 plans when developing Fj70 / Fj60? For the Hi-Lux it was a new design.

For other manufacturers? I wouldn't even attempt it.

My point, which I obviously wasn't clear on, is that you can't use the argument that SR is bad because Toyota didn't design it that way. Toyota Engineers used SR is their design of the Hi-Lux. So it must not be terrible. After 85 they abandoned that in favor of IFS for the Minis, and Coils for the 80's.

Originally Posted by vk7ybi

Theres always those that argue SR must be better because Hiluxs and 4Runners are SOA and SR from the factory, but Toyota has had to put measures in place to counteract the effects of doing so..

Can you please detail what those "measures" were "to counteract the effects of doing so"?

[vk7ybi]