octanejunkie
Elite Member
Outboard shock mountWorst case you could drill the the hole in the shock coil plate longer if you have too.I am not sure of its diameter though.
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12mm Rear Shock Upper Threaded Shaft
- Thread starter jross20
- Start date
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octanejunkie
Elite Member
The LC shock uses the same size bottom bolt as stock, just compare to that but I suspect they accounted for that since you discussed 3rd gen with them.
FWIW, I'm running LC shocks and did not drill out the top mount but I'm also not using the LC centering washer. I made a 1.2" copper shaft bushing for the pocket and used a 3/8" hose over the shaft and stacked the LC dampeners over that. This holds the shaft centered and allows flex and articulation.
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jross20
New member
Oh wow that sounds cool.
Yeah I still want to get a picture showing the flex limitation with the stock top hat washer between the 3 shocks I have. Not exactly scientific testing but good enough visual testing.
That’s what’s interesting though, it’s only 1/2” longer on the compressed length but has like 2” more travel. Fitting 9.25” of damper rod into a 14” compressed length is surprising to me at least
jross20
New member
Perhaps it is improved technology? Perhaps certain parts can be made thinner without compromising structural integrity? Or perhaps some shots like the Land cruiser ones are not as optimized as they could be? As in, maybe it's bulkier than it really needs to be because it was cheaper or something.
I wish we had a guy with one of those like water cutting machines, somebody that could like take shocks and cut them in half long ways.
jross20
New member
Alright, finally got the damn shock top hat washers.
I've got a local ship who quoted a good price on swapping the rears so now that I've got all of the goods I'll work on scheduling with them. As much of a pain in the ass the rear shocks are and with how hot it is down here... I'll gladly let them do it... haha.
I am actually a bit worried about the coils being too short...hopefully they are not. Does anyone know if rear wheel travel is higher during flexing than just having the truck up in the air?
I've got a local ship who quoted a good price on swapping the rears so now that I've got all of the goods I'll work on scheduling with them. As much of a pain in the ass the rear shocks are and with how hot it is down here... I'll gladly let them do it... haha.
I am actually a bit worried about the coils being too short...hopefully they are not. Does anyone know if rear wheel travel is higher during flexing than just having the truck up in the air?
I think it depends on what kind of rear links you have and if you have a sway bar. If you have a sway bar and your not running modified links I don’t think the travel will be much more being flexed vs drooping. Sway bar is probably the first thing to bind and limit the travel
jross20
New member
Ah I see. Hopefully that holds true. Though the free length of the 890 is pretty tall this might push it to the limit... Haha. Keep your fingers crossed that the good coils don't get loose when I do a flex test after installation.
:lookout:
I'm also going to take and post pictures from my rod diameter testing today when I get the chance. It's actually pretty wild, assuming the old shocks that I have are OEM... their articulation within the confines of the top hat washer/shim is pretty much insane. Probably way more than you would ever need.
You know I think somebody said the stock upper shaft is 10 millimeters, I'll get my caliper out and see if this one is because it definitely seems crazy small.
phattyduck
Elite Member
Travel at the springs is less when flexing (inboard of the shocks), travel at the wheels is more when flexing (outboard of the shocks).
Jumping/bouncing is when springs fall out in the rear, generally.
-Charlie
jross20
New member
Previously when I had 906's they become loose at full flex. i.e. full flex being driving up a steep hill and one rear tire flexing down while the other compressed up. Once I switched to 890's the problem went away. I mean I could just about remove the coils while she was flexed lol.
phattyduck
Elite Member
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
jross20
New member
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
jross20
New member
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:
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?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:
Scramble
New member
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?
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GhostRing
Member
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?
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?
jross20
New member
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.
octanejunkie
Elite Member
jross20
New member
Which year? By chance do we have specs on them? Specially the free length. :hungry:
