Sorry, just don't get what shackle reversal accomplishes

[vk7ybi]

Originally Posted by greenfox

The minis also had a anti rap bar on the front to keep the axle from moving in hard braking plus to help with axle rap.

Which in effect controls the castor.. Therefore, I call it a castor control rod.

[Cruiserdrew]

I have SR on my FJ40, and had it in it's previous iteration when it was spring under. It's biggest advantage is 1 thing--better approach angles. I have to say that for a rock-crawling truck, it's better. Since I don't DD my 40, and in fact only drive it to wheel, it works OK for me. I probably would not choose to do it again, but then it works great in its application.

The down sides out weigh the benifits I think. It's more work, you loose the theoretical anti-dive, and in most cases will benifit from a long travel front driveshaft which adds $200 to your build costs.

[vk7ybi]

Consider this.. In the 80 series, the control arms are setup as a leading link, just as the rigid half of the spring is in the 40 series.. Why, if rigid half of spring forward, or trailing link is better, didnt Toyota make the 80 series control arms trailing, forward of the axle?

[67azcruizr]

The last time this topic surfaced there was an excellent response.

[ojaij40]

UHHH,..HE HE,...NEVERMIND, (SHEESH) GLAD , (I mean ) SORRY I asked<.....

[theo]

Originally Posted by ojaij40

UHHH,..HE HE,...NEVERMIND, (SHEESH) GLAD , (I mean ) SORRY I asked<.....

No way Jose. This is one of the better discussions. It's relevant and there's no BS or bad blood. What could be better, other than bringing Junk's momma into it?

[CrznDawg]

I think it is a matter of choice. Chevy's have had SR on their full size rigs for years. Now, maybe they implemented some things to protect the t-case from the drive shaft. Who knows. The point is, both systems work.

I agree that if one was to replace the front shackles with new springs, new bushings, new shocks, power steering, new tie rod ends, etc., they would have a great ride. Likewise, if SR was done, and most of the things mentioned above were done at the same time, SR would produce a great ride. I think it is a moot point.

Now, if I wanted to do something that would help on road manners, I would lengthen my wheelbase. I cannot think of something that would have a more dramatic effect on road manners. Driving an FJ55 with bad springs/shocks/bushings vs. an FJ40 with same issues, the FJ55 drives better. I think if you wanted to make the vehicle more road worthy, that is what I would do. Just my opinion though.

Of course, I would replace my shocks, springs, bushings, tie rod ends, power steering, etc. in the process.

[colangut]

Most OEM manufactures use shackles in front with spring under and shackle reversal with spring over. Jeep used the front shackles until 1995?

Toyota went to rear shackles on the mini with spring over.

Can anyone point out an OEM application that this does not apply to? I am sure there as to be one but in general it seems to be the case, at least in North America.

[KY854RUN]

Originally Posted by greenfox

The minis also had a anti rap bar on the front to keep the axle from moving in hard braking plus to help with axle rap.

Originally Posted by vk7ybi

Which in effect controls the castor.. Therefore, I call it a castor control rod.

The anti-rap bar or castor control rod, as you are calling them, was not designed into the `79-`85 mini truck to control castor or to prevent axle rap. It was designed into the system to maintain proper steering geometry and prevent bump steer. The solid axle mini trucks use a drag link that runs along the driver's side of the frame and the torque link (anti-rap bar or castor control rod) runs parallel to the drag link. This maintains the proper steering geometry. I have experienced driving with the stock steering when the torque link is not connected and the truck had bad bump steer. When converting to crossover steering, the torque link is removed because it is no longer needed. I have crossover steering now and the truck drives fine without the torque link. In fact, it drives better with the crossover steering.

What needs to be addressed (other than SR itself) when doing a SR on a FJ40 are, the increase in the amount of slip joint travel that occurs and the greater angle changes of the axle end drive shaft U-joint. Toyota addressed this on the mini trucks by pointing the front differential more directly at the transfer case and using a longer slip joint and a double cardan joint (CV) on the front drive shaft.

All that said, I have driven both. A SR does have a bit less road wonder than the stock FJ40 design. The stock design works quite well when everything is nice and tight, but tends to wonder more when bushings and tie rods are worn.

[vk7ybi]

Originally Posted by KY854RUN

The anti-rap bar or castor control rod, as you are calling them, was not designed into the `79-`85 mini truck to control castor or to prevent axle rap. It was designed into the system to maintain proper steering geometry and prevent bump steer.

The only way bump steer can be caused in the Hilux setup is with the axle wrapping.. If the axle is wrapping, the castor is changing.. If the rod stops the bump steer, by maintaining geometry, then its crontrolling wrap and therefore castor.. It serves two purposes..

[PacToy]

I asked the same question long time ago to a friend.

The answer for me was that SR improves the road manners and a lot of Americans do it because we typically drive 40s at higher speeds in North America.
End of answering my question but it always stuck.

Actual scenarios I experienced:

In Okinawa I have a BJ-44 and my friend has a BJ-44, both had SOAs, mine w/ SR and his with shackle forward.

I could always go into the on/off ramps (typically 280-360 degrees) harder and faster with my SOA SR than that of my friend's SOA shackle forward every time. My SOA SR was sticking and turning harder in the on/off ramps than my friend's SOA shackle forward BJ-44. I didn't have the same "plow effect " in hard cornering that he did with the same SOA shackle forward set up.

However, in the same regards, my friend ALWAYS had better front axle articulation off road with his shackle forward than I did in the same situation with my shackle reversal.

I'm speaking from experience with two of the same 44s with SOAs. SUA SRs, I have no experience or knowledge. It just always stuck with me that it was done for better high speed road manners.

[lcwizard]

Actually the write up is pretty weak. Brake dive is far more dependant on spring rate and shock damping than shackle reversal.
And to cite the expertise of the engineers at toyota saying they must have had a reason is even weaker. Every concept of the FJ40 was stolen from pre existing
military vehicles, mostly WWII era US military. If the engineers had done everything right in the begining what's with the F motor? How about the non sychro 3 speed? Or the drive shaft e-brake. And why are we so quick to discard the 4-wheel drums with the ridiculous double cylinder per wheel arrangement.
I won't even mention the steering.
The truth is toyota was not the most advanced auto builder in the 50's. They borrowed everything right down to the motor arrangement and the exact tranny
to bellhousing bolt pattern.
Despite the arguements against I will continue doing shackle reversals on my vehicles. Because they work better off road and on. I personally like the improved approach angle and the fact that I can drag the bumper up and over a rock face without worrying about damaging a shackle.
I will also always replace the toyota engineered crazy link steering with power

Originally Posted by vk7ybi

Theres a nice writeup by Jim C here somewhere e 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..

[amaurer]

Originally Posted by lcwizard

Every concept of the FJ40 was stolen from pre existing
military vehicles, mostly WWII era US military. If the engineers had done everything right in the begining what's with the F motor? How about the non sychro 3 speed? Or the drive shaft e-brake. And why are we so quick to discard the 4-wheel drums with the ridiculous double cylinder per wheel arrangement.
I won't even mention the steering.

This isn't a strong argument. Why don't Scion's come with V12's and heated seats? Creating a state of the art off road experience for us 20 years down the road was far from the primary design point; Toyota designed to meet a goal for a given cost. That why you ended up with drums, non synchro trannies, and a bullet proof but otherwise not groundbreaking motor.

You call it borrowing, but Toyota (or anyone else) doesn't pay their engineers to reinvent the wheel for every vehicle. All engineers, and every engineering company, are happy to borrow designs that work.

In a case like shackle position there is no real cost impact for the manufacturer either way. You can assume Toyota chose what they did for technical reasons. I've tried to outsmart Mr. Toyoda several times now and generally speaking I find that he knows his shit.

[KingBeeIII]

I bought my 40 when I was 19 and working at a grocery store. It was my only vehicle and I took it wheeling. My point is that it was my daily driver and I wasn't made of money so mods came one at a time. SR gave me much better handling on and off road for what was then a 25 yr old Cruiser (12 yrs ago, it's a 71). This was before power steering, before I redid the tie rod ends and after the 2" spring lift. I remember the first drive after it was done, thinking to myself, "Holy shit! What a difference."

I don't believe they got it right in '71. There is almost always a better way to do things. It takes trial and error and maybe not even so much error, just finding a better way. After all, we are driving 40's and not 25's. That in of itself should tell you something.

[KingBeeIII]

Originally Posted by amaurer

This isn't a strong argument. Why don't Scion's come with V12's and heated seats? Creating a state of the art off road experience for us 20 years down the road was far from the primary design point; Toyota designed to meet a goal for a given cost. That why you ended up with drums, non synchro trannies, and a bullet proof but otherwise not groundbreaking motor.

You call it borrowing, but Toyota (or anyone else) doesn't pay their engineers to reinvent the wheel for every vehicle. All engineers, and every engineering company, are happy to borrow designs that work.

In a case like shackle position there is no real cost impact for the manufacturer either way. You can assume Toyota chose what they did for technical reasons. I've tried to outsmart Mr. Toyoda several times now and generally speaking I find that he knows his shit.

I'm in no way an expert here, but after reading your post I'm lead to ask, was anyone else doing S/R's in the 70's? Could it be that it's just one of the improvements that time leads you to because it's a better idea?

[v6samurai86]

"Toyota engineers know best." What a terrible argument. Why are any one of you on this site if your truck is perfect stock? How many of you are running stock tires? I mean, you must all have some A/Ts...stock height? No? But...Toyota engineers know best, right? And you buy oil filters from Toyota too, right? You think drum brakes are superior to disk? Fuel injection...uh...should I go on?

I've read this entire post, and the "great" article by Jimbo or something, and see the only real arguments about a S/R are:
1) Cost
2) Cornering at 100 mph...or perceived

For 1)...get over it. You're spending a ton on your truck because you love it. You want it to be cool and perform well. A S/R is not that expensive when you look at the big picture. It should be part of your lift to do it right.

For 2)...wtf are you doing in an FJ40 and worrying about street performance? The last stock FJ40 I rode in had a 3 speed and I could almost get out and check his tire pressure until he hit 3rd gear. You like your FJ40 because of OFF-ROAD capabilities. At least most people do.

From personal experience, I can tell you a vehicle performs MUCH better off-road with a S/R than with the shackle forward.

Those are my personal BS's...here is a good link for some good technical arguments from people that actually work on these vehicles (and this particular part of the vehicle):

MAF Technical Info

You should really read and respect what the pros have to say, IMO.

[lcwizard]

Actually we'll never know what would have happened if the Land Cruiser had been completely "engineered" by toyota. Since the first Land cruisers were a production run ordered by the US government to 'Willys' specs, once the tooling is in place and the trucks start coming off the line it's hard to justify retooling for a low speed military truck simply to address an issue of road manners.

Originally Posted by amaurer

This isn't a strong argument. Why don't Scion's come with V12's and heated seats? Creating a state of the art off road experience for us 20 years down the road was far from the primary design point; Toyota designed to meet a goal for a given cost. That why you ended up with drums, non synchro trannies, and a bullet proof but otherwise not groundbreaking motor.

You call it borrowing, but Toyota (or anyone else) doesn't pay their engineers to reinvent the wheel for every vehicle. All engineers, and every engineering company, are happy to borrow designs that work.

In a case like shackle position there is no real cost impact for the manufacturer either way. You can assume Toyota chose what they did for technical reasons. I've tried to outsmart Mr. Toyoda several times now and generally speaking I find that he knows his shit.

[Pin_Head]

After having owned both, my experience is that the major difference is that one has the shackle in the front and the other has the shackle in the rear.

I couldn't tell the difference in ride and handling. If I did a lot of rock crawling, I would prefer the shackle in the back. If not, I wouldn't go to all the trouble.

YMMV

[67azcruizr]

This isn't a strong argument. Why don't Scion's come with V12's and heated seats? Creating a state of the art off road experience for us 20 years down the road was far from the primary design point;

I've tried to outsmart Mr. Toyoda several times now and generally speaking I find that he knows his shit

I couldn't agree with you more, this isn't a strong argument.

Why don't Scion's come with V-12's and heated seats?

What relevence does this have to this thread.

The analogy between mechanical refinement/improvement and personal comforts is lame.

[amaurer]

Originally Posted by 67azcruizr

I couldn't agree with you more, this isn't a strong argument.

Why don't Scion's come with V-12's and heated seats?

What relevence does this have to this thread.

The analogy between mechanical refinement/improvement and personal comforts is lame.

Hey now, all I'm saying is that lcwizard was asking why Toyota didn't have a synchro'd 3 speed and why they had 4-wheel drums. It wasn't because Toyota didn't know better, it was because drums and an older tranny won the cost-benefit argument...

Which is exactly akin to the example I gave. All that said, I was drunk last night when I wrote that post... at least I wasn't driving... or worse, wrenching.

I've never driven a SR truck, so I'll shut up, but I find the original article pretty persuasive.

[lcwizard]

I hope it was agood micro brew.
The one very valid point Jim makes is the driveline issues. This is ,however, an issue with lifting of any sort. The 40 , unfortunately, was equipped with very short splines. Both the sixty and the mini truck have longer splines and are available through a number of sources to replace the stock units.
A cheap fix in a pinch is to pop the grease cap ( the quarter size plug at the end of the splined tube) in the female end of the shaft and grind the shoulder behind the male spline to the outside diameter of the male splines. This allows the male end to actually travel into the yoke. probably good for an inch of travel.

Originally Posted by amaurer

Hey now, all I'm saying is that lcwizard was asking why Toyota didn't have a synchro'd 3 speed and why they had 4-wheel drums. It wasn't because Toyota didn't know better, it was because drums and an older tranny won the cost-benefit argument...

Which is exactly akin to the example I gave. All that said, I was drunk last night when I wrote that post... at least I wasn't driving... or worse, wrenching.

I've never driven a SR truck, so I'll shut up, but I find the original article pretty persuasive.

[inkpot]

Originally Posted by lcwizard

I hope it was agood micro brew.
The one very valid point Jim makes is the driveline issues. This is ,however, an issue with lifting of any sort. The 40 , unfortunately, was equipped with very short splines. Both the sixty and the mini truck have longer splines and are available through a number of sources to replace the stock units.
A cheap fix in a pinch is to pop the grease cap ( the quarter size plug at the end of the splined tube) in the female end of the shaft and grind the shoulder behind the male spline to the outside diameter of the male splines. This allows the male end to actually travel into the yoke. probably good for an inch of travel.

Howdy! If I'm not mistaken, one "cost advantage" of producing the original design was that both driveshafts use the same parts for the slip joint. Most rears, unless lifted with an extremely curved spring, don't require much travel in the slip joint. Front shackles on the original setup allows for using the same parts other than tube length. Individually, we all seek improvements that we "think" we need. We all want to go farther, faster, harder. A SR is a good option, but it is not mandantory. I used to have a 40 with a lot of recurve so I could fit 35's. No SR. Thought about it, figured it was a lot of work for a small gain. Now I have a 55 that is SR, as part of a SOA with a cut n turn. I wanted to run 35's, but I wanted maximum road manners. I used the original spring hangers/brackets, and just swapped them end for end. I like it. It works very well for ME. It's not perfect. If you don't like it, that's OK. I am getting by OK with the original slip joint on a modified CV setup, but eventually I will put in a longer one. Just about everyone that rides with me remarks about how smooth it rides over choppy terrain. John