Dobinsons 5th Gen T4R Suspension options - from Exit Offroad

I have taken two FJs through Fins and Things as well as a Lifted TRD Pro Tundra.

The problem is on the steep downhills with the lips. I drug my tail down it in my FJs and my Tundra. I am guessing the 4Runner may have the same issue so was looking for some height to maybe minimize this. Also the front end hangs out there so far, that has me worried as well.

I do plan on adding weigh, sliders, skids, roof rack, Mother in Law, a large sack of snakes... you know, the usual.
 
If you're not in a hurry, I'll be installing the C59-599 Rears and C59-300 Fronts on 5100s the whole way around. Once Mike gets them into the states and forwards them my way I'll be getting them on and I'll be sure to post photos. Fingers crossed I'll have them in by the end of the month. My desired goal is lift/level but low enough to get into my garage, throw the kayaks on the rack without too much trouble, etc. I anticipate the shock/spring combo will ride quite a bit better than stock.

I'm not particularly in a hurry however I feel I need an alignment sooner than later after installing my Coopers...experiencing a bit of highway wander and hasn't had an alignment since we bought it. Essentially don't want to pay for two alignments this spring/summer but don't want to hold off and fry the Coopers while making a decision on suspension.

polonusa, I'd be interested to hear your feedback on the ride quality for sure. Main thing holding me back from the Dobinsons front coils is that they are near stock ride spring rate at 586lb/in vs stock 580lb/in (most consistent number I could find upon researching). My goal, as is many other 5th gen owners, is to eliminate the nose dive and get a slightly firmer on-road ride; not sure if this can be solely achieved by 5100's set on 0 (I understand that increasing 5100 clip to 0.85 or higher some are experiencing a "harsher" ride and I want to improve the ride...but I digress, this thread is about Dobinsons!). Other than a mild lift and given the similar spring rates, what are the additional benefits of going Dobinsons over stock? Mike can you speak to this? Should we expect a significant improvement over stock coils?

Also out of curiosity and in trying to better understand the principles of suspension design and application, I noticed for front coils the C59-302 spring rate for "100-220lbs heavy load" is the same as the "stock" Dobinsons at 586lb/in. Is the idea that the additional load/weight on the coil is "neutralized" (for lack of a more appropriate technical term) by the additional lift at 2" compared to the lower lift heights?

Edit: answering my own question ha - found some info here on 4th gen thread in case anyone here is interested.

"Front Coil Options, without KDSS.
C59-238 - Stock front end, low height lift, 0.75-1.0" lift. 375/375mm, 17mm wire, 586LB
C59-300 - Stock front end load, 1.75" lift. 385/385mm, 17mm wire, 586LB
C59-302 - 100-220LBS heavy load front weight, 2" lift. 395/395mm, 17mm wire, 586LB"

I hope I'm not muddling up this thread too much; please let me know otherwise and I'll gear down. I'm just trying to learn and increase my knowledge base and make an informed decision before just slapping on any suspension. Additionally, I'm doing this upgrade primarily for function to fit our family lifestyle/adventures although looks are a bonus and admittedly I always gawk at any modded/lifted Toyota trucks I see around...wife always rolls her eyes but generally supports my Toyota truck obsession :wacko:
 
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I'm not particularly in a hurry however I feel I need an alignment sooner than later after installing my Coopers...experiencing a bit of highway wander and hasn't had an alignment since we bought it. Essentially don't want to pay for two alignments this spring/summer but don't want to hold off and fry the Coopers while making a decision on suspension.

Check your tire pressure. If they're mud terrains, they do wonder more than highway or AT's, especially if they're over-inflated.


Probably best for you to do some forum research on how suspension works and all that rather than me rewrite it all out.

It's not just about the coils, but also what they're paired with. Soft coils with firm shocks give XXX type of ride, while heavier coils with soft shocks give XXX type of ride. Like you said, if you put in some coils on 5100s and raise the seat right up, it will ride different than at the lowest setting.

I know our struts and shocks are softer valved than OME. I took OME suspension off my 2014 Trail (was on it when I bought it), and their front spring rate is almost the same as ours (586 vs 590). The front softened up considerably, all because of the struts and their valving.

I haven't yet been in a truck with 5100's and our coils, but will probably here soon, so that I can see how the shock valving is.
 
Check your tire pressure. If they're mud terrains, they do wonder more than highway or AT's, especially if they're over-inflated.


Probably best for you to do some forum research on how suspension works and all that rather than me rewrite it all out.

It's not just about the coils, but also what they're paired with. Soft coils with firm shocks give XXX type of ride, while heavier coils with soft shocks give XXX type of ride. Like you said, if you put in some coils on 5100s and raise the seat right up, it will ride different than at the lowest setting.

I know our struts and shocks are softer valved than OME. I took OME suspension off my 2014 Trail (was on it when I bought it), and their front spring rate is almost the same as ours (586 vs 590). The front softened up considerably, all because of the struts and their valving.

I haven't yet been in a truck with 5100's and our coils, but will probably here soon, so that I can see how the shock valving is.

Thanks Mike. I'll check tire pressure. And thanks for the info on shock valving etc.

I have done quite a bit of research and reading up on suspension the last few weeks (over 40 bookmarks from this forum and others, taking notes along the way etc) but was more curious of the offerings and performance of Dobinsons given my goal to reduce nose dive and improve ride quality. Not trying to get into, "this is better than that" but just want to ensure that I choose components that best fit my application. Upgrading suspension is a big investment and want to be sure I exhaust all options before I follow the "buy once, cry once". Perhaps I'm also suffering from analysis paralysis, ha!

Thanks again.
 
So for a '16 trail with kdss, what would be the best rear coil to pair with eibach 620 lb front coils with 5100s set at 0 to achieve a leveled look?
 
So for a '16 trail with kdss, what would be the best rear coil to pair with eibach 620 lb front coils with 5100s set at 0 to achieve a leveled look?

I'm not sure. How much lift do those coils give? If the front is 2", then most would go with 1" to 1.5" on the back. If they're 2.5" front, then the 1.5" rear would work well. It all depends on how level you want it, and also if you have extra weight on the back. 200LBS of load can drop the rear 1/2" easily.
 
Just updated the first post, as I didn't have the rear shock lengths listed, and I also didn't have the proper extended length in my spec sheet here. It's longer than I thought (that's what she said....), 24mm/1" actually.

Rear Shock Options
GS59-701 - Twin Tube, suits 0-2" lift. 605mm extended, 362mm compressed
GS59-575 - Twin Tube, Long Travel, suits 3" lift (3" bump stop spacers recommended so shocks don't bottom out). 730mm extended, 425mm compressed.
 
I'm not sure. How much lift do those coils give? If the front is 2", then most would go with 1" to 1.5" on the back. If they're 2.5" front, then the 1.5" rear would work well. It all depends on how level you want it, and also if you have extra weight on the back. 200LBS of load can drop the rear 1/2" easily.

I've heard the front coils give around 1.6, I guess I could set at .85 setting if needed to level front to whatever lift is achieved in rear. Which part number(s) would be the best option?
 
I've heard the front coils give around 1.6, I guess I could set at .85 setting if needed to level front to whatever lift is achieved in rear. Which part number(s) would be the best option?

Cool. So either the C59-599 or the C59-505's would be good. If you keep the front at 0, then the 599's. If you go up, then the 505's.
 
And, just to be clear, are those for a kdss equipped vehicle?

No, those I just listed are not offset, so not ideal for KDSS unless you are using a spacer on the front. If you use a 5mm spacer on the front right side, you don't need offset rear coils, you can use even coils. Also vice versa, if you use offset rear coils, you can use even front coils.

Rear Coil Options, with KDSS.
Our KDSS coils are 15mm taller on one side to go onto the US passenger side (right side) to compensate for vehicle lean
C59-723 - Stock rear end, 1.25" lift, offset height coils for KDSS leveling. 420/405mm, 17mm wire, 228LB
C59-725 - Stock rear end, 1.75" lift with 3rd row, 2" without, offset height coils for KDSS leveling (similar to C59-325). 430/415mm, 17mm wire, 228LB
C59-727 - 200-400LB heavy rear load weight, 2" lift, offset height coils (similar to C59-327). 430/415mm, 18mm wire, 271LB
C59-729 - 600-800LB super ridiculous heavy rear load weight, 2" lift, offset height coils (similar to C59-329). 430/415mm, 19mm wire, 333LB


The lowest height KDSS coils is the C59-723.
 
C59-505 - Stock rear end load, 1.25 to 1.5" lift. 405/405mm, 17mm wire, 220LB **NEW COIL**

DANK AF! thats "good news" in cool people talk. lol


lol nvm i'll get these since i have kdss...C59-723 - Stock rear end, 1.25" lift, offset height coils for KDSS leveling. 420/405mm, 17mm wire, 228LB

stupid newb.
 
For those who've installed the stock rear end 220lb/in coils, how are you finding the ride with little to no weight? I like the mild lift/coil height options but am concerned that it's just over a 20% increase in spring rate than the factory coils.

Thanks
 
FYI? Finally got my lift installed today. Thanks again Mike!

It sits level (no lean yet) and even with kdss it wasn't a horrible install at all.


It feels nice and solid.
 

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