Rear Shock Dilemma... Spoiled by 2.5s?

[Bumbo]

I lifted my 4th Gen using the following parts and setup.

Bilstein 6112 Series 2.5" body shocks with standard weight spring.
Bilstein 5100 Rear with OME 2895 rear coil spring.

Since the install I've logged about 8,000+ miles on two big road trips which included everything form on-road travel to off road trail riding in varying terrain from rutted out roads, technical crawling, and some dune/sand.

I've had a good chance to really put everything to the test and got to know the setup very well.

I am so impressed with the front setup, the ride on road is great and off road is really soaks up anything I have thrown at it so far. Dips, bumps, drops... it all feels well damped and controlled.

The rear suspension feels like I am dragging the ass end sometimes. It doesn't feel controlled as the fronts, and not really sure what to replace the shocks with. I am actually pretty content with the on-road drive, but off-road, the 5100s leave a lot to be desired.

I don't think its the springs, I am running stock to medium loads with a fridge and standard load out of camping gear, but it just doesn't feel as nice as the fronts over bumpy terrain. I get a lot of "chatter" from the rear 5100, I feel its a huge difference from the front 6112 setup.

Is there something out there that will match the fronts well? Bilstein makes a 5160 remote reservoir shock but my concern is the 2" body. Is it the valving on the larger body shocks that is giving me the feel/effect I am looking for or will a good 2.0 get it done?

The only other shocks I see are the ICON 2.5 (with and without adjusters) but I really don't to spend that kinda cash.

What would you match with the 6112 to level out performance?

 

[NinjaOne]

You already have the springs pre-loaded like they should. OME shocks are tuned to their springs and may give you the ride you are looking for. Cheaper than getting ICONs etc.

Another option might be Bilstien 5160s

 

[Inv4drZm]

Icon 2" rears would be a large upgrade from your 5100's. Just under 1" more travel. Actually 2" diameter vs 1.8" for the 5100. And rebuildable + revalvable.

Radflo/ Fox / King would probably offer similar performance and prices.

 

[Bumbo]

You already have the springs pre-loaded like they should. OME shocks are tuned to their springs and may give you the ride you are looking for. Cheaper than getting ICONs etc.

Another option might be Bilstien 5160s

I had a conversion with a couple vendors and both told me the 5160s wont be that much of an actual improvement over the 5100s...

Regarding actual dampening performance / feel they mentioned it would be similar to the 5100. The biggest difference is they would stand up to fade better on longer rides due to the external rez.

Its really difficult to verbalize what I am feeling between the front and rear setups... I was driving this one hard pack road with a lot of cobble stone type of rock the fronts just seem very plush and well controlled / dampened while the rears just presented a lot of chatter (in comparison).

The rears also seem to buck the end up a bit on bumps, almost like there is too much rebound where the front has good clean compression and rebound.

Im wondering if its the larger shock body thats delivering the characteristics that i like, or if its just a valving disagreement with me and the 5100.

Can a 2" body even be valved the way some of the larger shocks are valved?

 

[Bumbo]

You already have the springs pre-loaded like they should. OME shocks are tuned to their springs and may give you the ride you are looking for. Cheaper than getting ICONs etc.

Another option might be Bilstien 5160s

I might have to try the OME route...

Can anyone describe the OME vs the 5100, what could I expect to see different?

 

[Bumbo]

Icon 2" rears would be a large upgrade from your 5100's. Just under 1" more travel. Actually 2" diameter vs 1.8" for the 5100. And rebuildable + revalvable.

Radflo/ Fox / King would probably offer similar performance and prices.

Thanks, I will look into that too. The 2" ICONs were actually under consideration when I first purchased my setup, but im not sure why I went with the 5100 at the time.

5100 just seemed so popular I figure I try them... on road I think its one of the best OE replacements ive ever used...

What could I expect to see comparing the 5100 to the ICON 2.0?

 

[EdmundGTP]

I had a conversion with a couple vendors and both told me the 5160s wont be that much of an actual improvement over the 5100s...

Regarding actual dampening performance / feel they mentioned it would be similar to the 5100. The biggest difference is they would stand up to fade better on longer rides due to the external rez.

Its really difficult to verbalize what I am feeling between the front and rear setups... I was driving this one hard pack road with a lot of cobble stone type of rock the fronts just seem very plush and well controlled / dampened while the rears just presented a lot of chatter (in comparison).

The rears also seem to buck the end up a bit on bumps, almost like there is too much rebound where the front has good clean compression and rebound.

Im wondering if its the larger shock body thats delivering the characteristics that i like, or if its just a valving disagreement with me and the 5100.

Can a 2" body even be valved the way some of the larger shocks are valved?

The Billies are overheating and loosing their ability to dampen the suspension. Drive with some speed for a couple miles over a rough patch of trail. Stop and reach behind your wheels to feel how warm the front shock body is vs. how hot the rear shock body will be. I was actually VERY surprised at the first time I bothered to feel how warm/hot shock bodies would get after driving. I had no idea they could get so hot, but it makes sense.

Increasing the volume of dampening material (i.e. larger diameter shocks, and/or remote reservoirs) will help immensely here. Whichever way you go about doing it, you will notice a big improvement. After that, you can decide whether or not re-valving the shock is a priority or even necessary. You may very well find that it's not.

 

[Bumbo]

The Billies are overheating and loosing their ability to dampen the suspension. Drive with some speed for a couple miles over a rough patch of trail. Stop and reach behind your wheels to feel how warm the front shock body is vs. how hot the rear shock body will be. I was actually VERY surprised at the first time I bothered to feel how warm/hot shock bodies would get after driving. I had no idea they could get so hot, but it makes sense.

Increasing the volume of dampening material (i.e. larger diameter shocks, and/or remote reservoirs) will help immensely here. Whichever way you go about doing it, you will notice a big improvement. After that, you can decide whether or not re-valving the shock is a priority or even necessary. You may very well find that it's not.

At first I thought it was shock fade but it still presents me with what I dont like when the rig is cold... so its not fade but I do understanding what you are saying 100%

It sounds like my best bet is just to get a 2.5" shock and see how it goes, I was just hoping there was some magic middle ground to save a few bucks.

I really didn't want to go that high end, but the 6112 system has given me a taste of what good stuff really is... at least to the point where I consider that the "magic middle ground" because I wont be swapping them out for an ICON, Fox, or King setup unless I need to go higher up forcing me to buy UCA in the process...

 

[RonJR]

The OME 2895 is a considerably stiffer spring than the stock spring. (250 lbs/in vs 180). The 5100's are valved for stock rate springs, and simply don't have enough damping to control the stiffer spring. I'm not sure what shock you need, but the 5100 isn't it. You have to match the shock to the spring for optimum results. Any good aftermarket shock manufacturer should be able to tell you which of their shocks will match your spring. It's all math and engineering, not cut and try guesswork.

 

[Inv4drZm]

What could I expect to see comparing the 5100 to the ICON 2.0?

My brother's FJ with lots of added weight and Icon 2.5" coilovers has the 2.0 rear shocks, they keep up just fine with the fronts. No complaints whatsoever. He has 34's, 120lb front bumper + winch. Skids, sliders, roof rack with the regular Icon 2" lift coils in the rear.

 

[Bumbo]

The OME 2895 is a considerably stiffer spring than the stock spring. (250 lbs/in vs 180). The 5100's are valved for stock rate springs, and simply don't have enough damping to control the stiffer spring. I'm not sure what shock you need, but the 5100 isn't it. You have to match the shock to the spring for optimum results. Any good aftermarket shock manufacturer should be able to tell you which of their shocks will match your spring. It's all math and engineering, not cut and try guesswork.

Thanks for an answer with some actual numbers... that makes a lot more sense to me...

Thinking back on how this things feels, your explanation regarding dampening seemed to hit it on the head.

Do you have a recommendation on a replacement shock that pairs well with the OME 2895?

Just thinking out loud here... the only time I felt under-sprung is why I had one of those harbor freight hitch mounted carries with a bunch of liquid in it... cooler, gas can, water jug. Not often I carry that much weight off the axle, but it was pretty noticeable. I guess thats what I can expect after throwing a bumper on this thing in a year or two.

 

[Bumbo]

My brother's FJ with lots of added weight and Icon 2.5" coilovers has the 2.0 rear shocks, they keep up just fine with the fronts. No complaints whatsoever. He has 34's, 120lb front bumper + winch. Skids, sliders, roof rack with the regular Icon 2" lift coils in the rear.

Thats good to know, thanks.

Seems like the valving I want can be had in a 2" shock... and the reason to go remove rez or larger body also has to do with fade? Just more oil and more fluid to have for dampening?

 

[Inv4drZm]

Thats good to know, thanks.

Seems like the valving I want can be had in a 2" shock... and the reason to go remove rez or larger body also has to do with fade? Just more oil and more fluid to have for dampening?

Yes, more fade resistance. Although different trucks and spring setups, my 2.5" remote resi's all around ride similarly to my brother's 2.5" front 2.0 back on-road at least.

 

[Drunner97]

Icon 2" rears would be a large upgrade from your 5100's. Just under 1" more travel. Actually 2" diameter vs 1.8" for the 5100. And rebuildable + revalvable.

Radflo/ Fox / King would probably offer similar performance and prices.

^ This, you can get the 2.0 Icons pretty cheap and there are a couple vendors doing group buys right now if you look in that section.

Thanks, I will look into that too. The 2" ICONs were actually under consideration when I first purchased my setup, but im not sure why I went with the 5100 at the time.

5100 just seemed so popular I figure I try them... on road I think its one of the best OE replacements ive ever used...

What could I expect to see comparing the 5100 to the ICON 2.0?

You'll notice a much better ride. The best I can come up with is that even though it says the 5100s are good for a 2" lift in the rear, the shock itself isn't built for it. More of a 1.5" lift in the rear. Myself and a couple others were having issues, especially with the Superflex/5100 combo, because the 5100s are bottoming out and creating a harsh ride. They couldn't keep up with the 2" rear lift. Once I moved to Icons and Metal Tech springs I couldn't be happier with the way my 4runner rides on and off road.