OME Dakar spring help

I'm starting to make a few small changes with my rear suspension on the Tacoma and could use some help. My plans include relocating my rear shocks, a ubolt flip and some bumpstops.

the bumpstops are what brings me to my question. The reason for bumpstops is to keep the springs from flexing into negative arch and to keep the tires out of the body. I remember talking to Kurt at Cruiser Outfitters (who knows as much about the OME products as anyone) about the time I got my suspension from him about how the Dakars are designed to not have much arch to them even when new. Something about the best ride when the springs are closer to flat. So a few details about my setup. I'm using standard Dakars with the extra leaf and 1.5" over stock shackles from AllPro.

As I consider how to handle my bumpstops if I make them in a way to keep the springs from going into negative arch, I'm basically going to have zero uptravel. Take a look at this photo from today. This is basically a fully empty truck. But it is carrying the weight of my shell, along with the rear bumper with swingout/spare/can carrier (cans are empty). All told I'm guessing there is about 275lbs on the rear of the truck.



As you can see the springs are already essentially flat. If I load the truck for a typical trail/camping trip it compresses to negative arch. I don't feel like I need more lift as the truck sits at a good ride height, but I'm concerned about how much I'm fatiguing the springs by having them go into negative arch too often. I want to set up the bumpstops correctly but I don't want to kill all my travel.

As it sits currently I don't think the bumpstops are adequate. Here's the same spring at full stuff. Probably not the best to do this all the time. (note: the wide angle lens is probably making this appear a little worse than it really is, but you get the idea).



same spot to give you an idea of how the tire is stuffing into the wheel well. Seems reasonable to me but I'm not sure about what it's doing to the spring.



So, i'm looking for some help and suggestions. I really like the Dakars and have been very happy with the performance, but should I be looking at a different spring for how my truck is set up? I don't want this to turn into a thread of people just posting a bunch of different springs. I'm looking for some actual technical help.

 

How old are those springs?

It seems kinda odd that they would design a spring to always go into a negative arch anytime the suspension cycles upwards. Also, it looks like your shackle doesn't move at all when the suspension cycles up either. Shouldn't it pivot backwards just a little bit?

 

What is the part # for those leaf springs? I wouldn't worry about the negative arch on the spring. But I would set up the bumpstops so that they make contact a little before your shocks bottom out.

 

Springs are about 2.5 years old. the springs aren't necessarily designed to go into negative arch, but they are designed to to have very mild arch to them to be in the optimal range for ride quality (which happens to be close to flat).

The shackle actually moves as it should. The reason it looks like it hasn't moved in those pics is because in negative arch the spring has moved beyond its longest length and as the spring deflects in the opposite direction is essentially shortens the spring again which will pull the lower shackle pin back inward.

 

Good to hear. That's was my plan. I'm not bottoming out the shocks but its close.

rear springs are these:
OME Dakar CS 046R A/B Rear Leaf Springs

Also using the D6XL AAL

 

You have the correct springs. That is good. I would just work on the bumpstop setup. Since you have a lift shackle as well, your springs are going to go more negative than they would have with out it. Make the bumps a little taller, and maybe focus on new shock mount setup so you can run some longer shocks to take advantage of downtravel.

 

Cool that's exactly my plan, although in the process of relocating the shocks I'm going to see if I can set it up with proper angles to utilize the Nitrocharger shocks and still get better travel.

If the measurements don't work out, I'll be looking at different shocks.

 

Adam ive thought about this alot too... is ur reason for relocating shocks purely because u wanna do the shackle flip?

when i did my shackles(similiar to urs) i realized i needed longer shocks. i also was concerned with the shocks hitting the mounts when at full droop. i noticed at full droop the shock top mounts pivot more than i originally planned. i positioned my ome shock so it would extend straight towards the bottom mount. it was very close to hitting the mount abut an inch down from the eyelet. then i compared my ome shock to a bilstein, huge difference in the tube width, so i knew id be ok on clearance.
i also measured for shocks by flexing my truck on my lift at work. i would lift the truck until a rear tire came off the ground. that was essentially my max droop on one side and max compress on the other. that told me my springs could physically not compress anymore or extend anymore.... i measured both sides and bought 5125s that were an inch longer than i needed and an inch shorter than what i needed. so essentially my shocks do nothing to my rear suspension other than dampen the ride when driving normally i do realize i am not utilizing bump stops, they are about an inch away from hitting at full stuff.

now, i am planning on 285 soon. i am planning on bolting them up and seeing if they rub at full stuff. if they do i will measure how tall my bump stop would need to be to keep them from rubbing. theni will do the u bolt flp and install the said length bump stop. i then plan to flex it out on the lift once more so the bumps hit and then place my 5125s at /\ angle and place them accordingly so compress and droop both fit on the cross member and my mounting position on the axle housing.

i know alot of rambling... lol i think suspension geometery is fun as hell to play with. but bottom line i think
* you dont want your shocks to act as limit straps or bump stops.
so... set up ur suspension with no shocks mounted first so it articulates as desired, then mount shocks where they dont inhibit ur articulation

 

thanks Jace.

Actually my reason for relocating the shocks is because in the factory location they are limiting travel. The ubolt flip isn't necessary I guess but I figure....why not change it, right? If the lower shock mount isn't on the ubolt plate any longer, might as well gain a little clearance by doing the flip.

As for the process of relocation of the shocks and figuring the length, yeah pretty much the process you described.

 

are theshocks really limiting travel? u do have the aal so that's different than me... but mine arent? and yes i agree totally, might as well gain clearance. I assume you are gonna make your own crossmember?

 

Yeah I definitely have more droop when the shocks are off. The AAL hasn't seemed to limit travel at all.

Yeah I'll be making my own crossmember.

 

cool, sounds good when are you plannin on tackling this? ill expect pics

 

hopefully soon but I'm never home....still working on crazy deadlines at work and I need to finish a few more bedracks for people when I have a spare couple hours. but it will happen before Moab.

I'll take pics for sure.

 

cool man, sounds good. excited to see that thing setup like this /\

 

subbed because I'm doing the same thing...

Adam do you plan on mounting shocks like l l or / \


This guy relocated his like this l l... start at post 9 he boxes his frame and added a crossmember. Im starting to think of something similar

 

hey, just looking at this a couple thoughts come to mind. the 1st is the use of the OME rear shocks. they are what, 23.94 inches extended..? why not try a procomp that is 25.75 extended and avoid relocating the mounts, here are the details on the shock;
32551X 25.75 15.04 10.71 Stem Loop 2.36.
this gives you 2 extra inches of down travel/articulation on the shock, but yes, it is about an inch and change longer than the OME when compressed which goes back to your bumpstop needs. when doing the ubolt flip, you have a flat plate that you can drill holes in to mount your stock bumpstop to, to do it cheap you can also have this spaced up with a metal plate between the mount and the spacer and weld in place or pay somebody to weld in place to give you an increased height in your bumpstop. alternatively apparently all pro makes a bumpstop for the flip kit, never seen it but read that it exists.

 

Nice truck box rocket.
It looks like in the second pic your bump stop is not hitting the strike pad on the frame.
I relocated my rear shocks too || I would recommend the || setup. From what I have seen from the /\ set up it just kills the shock bushings and the flex is no better than || and the ||setup is better on road.
Check out my build on how I did mine but I do recommend mounting them with less angel then I did

And you will see my fix for the bumps not hitting the strike pad.

 

hello Box rocket, First off i would like to say you have a bad ass ride and props you have inspired alot of ideas for my truck. Addressing your leaf spring issue, i have some experience with them but, i am NOT a suspension guru by any account, i am still just leaning all of this. But i have an engineering degree for whatever that is worth anyways. I see the Dakar packs dont have a thick overload spring in the pack like the OEM do, In my opinion that helps them from over articulating and becoming concave in stuff. Since after the go flat they hit the already flat overload spring and try to bend that, not happening. The leafs are made of spring steel so they will flex back but since you did loose arc in the spring pack/rear lift, from when they were installed, it would seem that at some time before you did exceed the total flex of the pack and went into plastic deformation of your springs. Maybe putting your old overload spring in from the toyota pack would of helped this in the beginning and prevented all this I'm not sure, but it would prevent the tire from stuffing as much and limit up travel but not hinder droop. also it would lift the back the thickness of the overload spring about 3/8 -1/2" Just my observation for what ever its worth.
Dont know if the length would work with the Dakar's, are they longer than the original springs ??

PS I have read your build thread and that is how i know you lost lift in the pack before.

 

Thanks for the reply. I got it sorted out. There is nothing wrong with the spring packs. I've been looking into this for a while now and it's all good. OME does not use a thick overload like OEM. They use two thinner overloads so there is a more progressive limiting of flex. The top overload will flex a little bit and once the second overload is in contact the flex is limited. everything is working as it should.