The 906's are pretty short - definitely need to have stock length shocks for them. I have 5th gen springs, and they are even shorter! Even with a 10mm trim packer, they are loose at full droop with 5100's (stock length). I'm planning on moving to 906's at some point - I don't need the extra travel and I could use the progressive winding for better weight handling.

-Charlie

You know I honestly thought that the 890's rode much better than the 906's. I've loaded the back with a decent bit of stuff a few times and the 890's have never sagged. I've never had a trailer hooked up but I do want to check that out and see how they handle it

All right so here's my super non-scientific comparison shots.

They're not exact but they should give you a pretty good idea. Clearly the stock shot has ridiculous articulation, but I'm pretty sure that it would never need anywhere near that much. If somebody can post a picture of what their rear shocks look like at maximum flex I think that would give us a good comparison. As in, sure the Dobson doesn't have as much articulation, but is it still more than enough for what's actually going to be usable?

Stock w/ 10mm Shaft:


Dobinson 4th Gen w/ 12mm Shaft:

Probably still more articulation than would be usable or needed. So what did you end up doing for the centering cone/washer and bushings?

The 906's are shorter but stiff so a softer stock length shock is required if you want a smoother ride. If you were using the LC shocks with those they are way too long. The 890's are taller but can be bouncy without some weight in the back or a stiffer shock from a heavier truck like a 4th gen or LC. Now to confuse you more, 890's will sag overtime if you put a lot of weight in the back like an aftermarket bumper with tire carrier. Also your stance loaded and unloaded might be important to you. Just think about the future mods you have planned where you will be adding weight. You dont want to do your lift a second time. I read hundreds of lift threads for a year before I decided I what my best options would be. Those lift threads have opinions from owners that have used all kinds of combo's and you can learn a lot from guys that have redone their lifts 2 and 3 times! LOL Dont forget tires have a big effect on ride quality. E rated truck tires ride like shit on our rigs. But if you have a short ride to the trail, dont DD it and wheel every weekend they're gonna be fine. If you're mostly a pavement princess, pass or C rated tires would be better. I have pass rated HWY tires on my Limited because it never goes off road. They're quiet, comfortable and get great MPGs. My lifted 4runner has D rated mud tires because its 50/50 pavement/off road and I have very long drives to the trails. Good Luck!

PS: Thousands of forum members here have used 4th gen Bilsteins with 890's over the years with no issues. I dont see why the Dobninsons would be a problem?

Gettin' there!

Slightly random questions: Say I get the 3rd gen valving - but decide to outboard mount these, how much (if any) am I affecting the damping?
In my head, the outboard puts the shock more perpendicular to the axle, potentially changing the rate of compression. Am I overthinking that?

I just jacked mine up until my coil was loose enough to fall out and it looked similar to what your showing with the dobinsons shock so I’d say you are good.

Attached Images

 

If you hadn't seen it, a few pictures back I actually showed that The doninson shock has longer travel than even the Land cruiser shock. Something like 9.25" of shock travel! In fact I think it's the longest that I've ever seen for 3rd gens.

You know I did spend a lot of time in the past but even though I did, I still ended up changing things later because even though I did a bunch of research I still learned additional things later that I never thought to search for... But I guess that's just how it goes.

Although really, is there anything else besides the 890s? In terms of if you wanted something just as long or maybe a little longer?

I'm not 100% sure either, but at the same time I would like to say that it would make sense if it did affect it. That would also change the length of shock you would need so you would probably really need to mock it up to see what kind of overall travel you need.

You know I've been thinking about this... I wonder if there's any way that some kind of a simple stimulation could be made that could allow us to simulate travel on the axle. Like if somebody who knew how to code or something wrote some basic little program and we put in the exact dimensions and everything of the frame and the axle. Something that would let you click and drag and like drag it around so you can get measurements and stuff.

LC springs

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Which year? By chance do we have specs on them? Specially the free length.

Lots of options depending on color code/year/trim
LC coil spring Color codes
LC color codes
Help Identifying Coils

Getting antsy to try out the shocks, so I would like to hear some thoughts on this?

My 50701's (which Dobinson's stated to me directly are the newest valving) came with a set of bushings for a Toyota Fortuner.
As you can see, the kit came with 2 washers & 2 bushings. No Centering/Index washer, or indication to use one.
They are also a softer compound that the 4th Gen bushings.





What is the drawback to simply installing it just like this? I figure any index washer essentially "becomes" the hole in the frame, and keeps
the shock shaft completely isolated in the bushing stack. That to me is the primary goal to allow safe movement as the post pivots inside the frame hole.

The combined height of the Fortuner bushing shoulders is equal to the bushing/washer intended for the 4th Gen T4R,
and the 17mm shoulder diameter equals the 3rd Gen frame hole. This (in theory) should still isolate the shaft during use, correct?

I do have the following concerns:

Index washers seem to exist for a reason, but I can't quite get my head around it...If they are sufficiently tensioned,
they should effectively be one with the shock frame hole. (imagine welding the washer in place)
I assume it shouldn't move at all during the shock cycle.
Is it simply the needed method to be able to utilize a cupped washer?
I am worried that under full articulation, the bushing will try to smush out
against the frame plate instead of staying tucked into the washers.
@ZSW99 image illustrates this bushing containment.

Second, due to the larger post diameter, the Fortuner bushing shoulder is
thinner than the 4th Gen's. Too thin? I mean Dobinsons provides these to
be utilized on a similar, alternate vehicle, so it's apparently acceptable...

So I am going to chuck these under there and see what happens.
I don't see the post snapping off suddenly, but the bushing shoulders
may not hold up. I know these are wicked long shocks, but between
the 890s and ext. bumpstops, I should hopefully stay out of trouble.

I figure at least this lets me see if the valving is even close to what I want
without having to drill out OEM holes, or fab up outboard mounts yet.

dunno if this has a bearing on the behavior of your shocks. but the fortuner has its rear shocks located behind the rear axle and coils are seated on the rear LCAs.

also, I am not sure about those bushings being able to hold out against the loads applied to it. I would rather have the stock cushion retainer if it works with the dobinsons shocks.
OME recommends that the stock cushion retainer be used with their bushings to ensure that the shock shaft is centered on the hole.

I'd have to get under there to see exactly what I used, but I basically used a combination of the washers and bushings that they sent with actual OEM ones. So like I did use the OEM centering washer.

Yeah I definitely would not install anything without using the proper centering washer!!

If you torque down the bushings enough, they will squeeze in the hole and become a sort of 'centering washer' all on their own. However I don't know how you plan on driving your vehicle so if you expect the rear shocks to do a lot of work, meaning off-road a lot, it may not work and be secure enough. My reference on this is the sway bar bushings as if you torque them down tight enough they will squeeze into the recess around the threaded bolt and fill the gap on their own.