Bilstein 6112 In

[Sauce839]

I'm sure many others have had this discussion in many previous threads, but I feel obliged to point out what I perceive as a misconception about "preload" when I see it.

"Preload" is only the amount of spring compression necessary to assemble the coilover for installation. It does not affect spring rate (assuming a constant-rate spring, which I believe all T4R front springs are). It does not affect ride quality.

A constant-rate spring requires the same amount of force to compress it a given distance whether it is "preloaded" or not.

In this particular case, a longer spring with a lower setting on the 6112s will still have the same amount of "preload" if the spring still needs to be compressed the same distance in order to assemble the coilover. Even if the "preload" is somehow less, if the new spring has the same rate as the shorter spring it is replacing, it will ride exactly the same. The longer spring will add the capability for more travel if the suspension is set up to accommodate it.

The perception of harsher ride quality due to "preload" is usually due to a combination of stiffer shocks and/or springs, and revised suspension geometry with the lift which transmits more vertical forces to the frame than the stock geometry does.

OK, I've got my Nomex suit on, but unless someone comes up with a really compelling argument against what I said, I will stick by it.

I think that makes sense to a point, but that wouldn't explain why the 600lb spring that came with the 6112's are that much stiffer than the 580lb stock springs. My understanding of pre-load was that you had to overcome the preload in order for the wheel to move.

Simple example, if you have a 600lb/in spring (which I believe the bilstein 6112's come with) with 1" preload compression on it, you only need to exceed 600lbs of load on that spring to get the spring to compress more. If you have 2.5" of preload on the same spring, you would need overcome 1500lbs to make the spring compress.

I know that's a simplified case and there are more things that affect the ride.

I'm new to all this, and am wading through all the (mis)information that is online. I'm open to suggestions on improving the ride... but I found this on another forum. I'm wondering if this is what I'm feeling, and in that case, I should probably either drop the front end, or see if I can find a long travel strut (ie. Icon).

"The higher your preload, the closer the shock is to being fully extended when the car is driving on a smooth road. If it is too close to being fully extended, then when you hit a bump it will fully extend and the wheel will leave the road. When the wheel lands, there will be a shock as the momentum of the chassis coming down overcomes the preload on the spring. Most people would feel that as poor ride quality."

 

[jasxn]

<--- learning as well.

 

[TEujunga]

inadvertent double post -- see below

 

[TEujunga]

Simple example, if you have a 600lb/in spring (which I believe the bilstein 6112's come with) with 1" preload compression on it, you only need to exceed 600lbs of load on that spring to get the spring to compress more. If you have 2.5" of preload on the same spring, you would need overcome 1500lbs to make the spring compress.

True, but it still takes only 600 pounds to compress it an additional inch no matter where you start from. The vehicle weight should be enough to compress the spring well past any reasonable amount of "preload." After that, the very definition of a constant-rate spring means that it always takes the same amount of force to compress the spring an additional given distance. Whether you're going from fully extended to 1" of compression, or from 3" of compression to 4" of compression, if it's a 600-lb. spring, then it will always take 600 lbs. of force to compress the spring that additional inch. I know it seems counter-intuitive, but if you think it through, you can visualize how it works.

Another way to think of it is that once the weight of the vehicle is resting on the spring, the spring doesn't "care" how much it was pre-loaded for installation. It's as if the preload never happened, unless you get into the kind of situation described below:

"The higher your preload, the closer the shock is to being fully extended when the car is driving on a smooth road. If it is too close to being fully extended, then when you hit a bump it will fully extend and the wheel will leave the road. When the wheel lands, there will be a shock as the momentum of the chassis coming down overcomes the preload on the spring. Most people would feel that as poor ride quality."

This is technically true, but I would think it would take an extreme amount of preload indeed to get into this type of situation with a T4R. The travel on aftermarket shocks should be more than sufficient to accommodate any reasonable amount of "preload" necessary to install the coilover.

 

[TEujunga]

Yikes, now I'm getting confused...

"The higher your preload, the closer the shock is to being fully extended when the car is driving on a smooth road. If it is too close to being fully extended, then when you hit a bump it will fully extend and the wheel will leave the road. When the wheel lands, there will be a shock as the momentum of the chassis coming down overcomes the preload on the spring. Most people would feel that as poor ride quality."

The more I think about this, the more I think it is incorrect.

The amount of shock extension at vehicle rest is determined only by the ride height and the overall length of the coilover assembly when fully extended. It has nothing to do with the amount of "preload" on the spring.

Moving up the 6112 spring perch position increases the ride height, which extends the shock and takes away from the available down travel, but the overall length of the fully extended coilover assembly remains the same.

Again, "preload" relates only to compressing the spring to install it in a coilover which is already at full extension. The length of the coilover assembly when fully extended is the same no matter how much "preload" the spring has on it. If you're routinely exceeding full extension of your coilovers every time you hit a bump, you need to slow down (or get a long-travel setup).

 

[Sauce839]

Yikes, now I'm getting confused...



The more I think about this, the more I think it is incorrect.

The amount of shock extension at vehicle rest is determined only by the ride height and the overall length of the coilover assembly when fully extended. It has nothing to do with the amount of "preload" on the spring.

Moving up the 6112 spring perch position increases the ride height, which extends the shock and takes away from the available down travel, but the overall length of the fully extended coilover assembly remains the same.

Again, "preload" relates only to compressing the spring to install it in a coilover which is already at full extension. The length of the coilover assembly when fully extended is the same no matter how much "preload" the spring has on it. If you're routinely exceeding full extension of your coilovers every time you hit a bump, you need to slow down (or get a long-travel setup).

I agree 100%, but if I think about it in that manner, even by replacing the spring with a longer one with the same spring rate (so I don't have the clip on the top ring) would result in exactly the same ride. The only way to provide a more compliant ride would be to swap out the springs for ones with a lower spring rate. But something about that still doesn't sit well in my head, or am I missing something?

The only option would be to look at the strut it self. The difference between the 580lb/in stock spring vs the 600lb/in spring from Bilstein(eibach) should have similar characteristics. The only thing that changed (minus the geometry) is the strut. How much stiffer is the 6112 over the stock?

I haven't seen rebound or dampening numbers on either one in any of the reading I've done.

 

[TEujunga]

Actually, I think you're correct. A longer spring with a lower spring rate could theoretically give you the lift you want while providing a more compliant ride -- but only if the revised geometry and the 6112 shocks would allow for it. Like you, I don't have any information on how much stiffer the 6112s are than stock.

It seems like a stiffer ride is just part of the deal when doing a lift of >2". Most people seem to like the stiffness; some don't. In all the lift threads I've read, if anyone has retained stock ride compliance after doing a >2" lift, I haven't seen it -- seems like most report their ride quality as "better" because they like the tauter handling and reduced nose dive.

If it's any consolation, my Toytec Ultimates set at around 2" of lift are noticeably stiffer than stock, too.

In any event, I'd say the increased stiffness is due to three factors: 1) geometry; 2) spring rate; 3) shock valving. Which of those factors contributes the most, and how exactly they interrelate, is outside my knowledge thus far, but I'm pretty sure that "preload" isn't itself a factor

 

[Sauce839]

Actually, I think you're correct. A longer spring with a lower spring rate could theoretically give you the lift you want while providing a more compliant ride -- but only if the revised geometry and the 6112 shocks would allow for it. Like you, I don't have any information on how much stiffer the 6112s are than stock.

It seems like a stiffer ride is just part of the deal when doing a lift of >2". Most people seem to like the stiffness; some don't. In all the lift threads I've read, if anyone has retained stock ride compliance after doing a >2" lift, I haven't seen it -- seems like most report their ride quality as "better" because they like the tauter handling and reduced nose dive.

If it's any consolation, my Toytec Ultimates set at around 2" of lift are noticeably stiffer than stock, too.

In any event, I'd say the increased stiffness is due to three factors: 1) geometry; 2) spring rate; 3) shock valving. Which of those factors contributes the most, and how exactly they interrelate, is outside my knowledge thus far, but I'm pretty sure that "preload" isn't itself a factor

it might just be something I need to get used too. Maybe a long road trip to bond with the truck.

Thanks for your input. I did find this tonight while doing some reading... seems like a pretty good explanation of preload.

Threaded Spring Preload

 

[ShaunStiffler]

The install went fairly smoothly, except we had coil spring compressors that couldnt get a big enough bite on the coil spring to compress... we used the lower control arm method instead.

What is the "lower control arm method"? Can anyone stepwise how to torque the lock nut? i.e. is the coil compressed or not when you torque the nut?

Also, im not sure how to find the torque specs for all other nuts/bolts that might be loosened during a lift and UCA install? i.e. lug nuts, top mount nuts, ABS and brake line bolts, bolts related to sway bar disconnect, upper arm-to-frame mounting bolt, etc. Thanks!

 

[Sauce839]

Actually, I think you're correct. A longer spring with a lower spring rate could theoretically give you the lift you want while providing a more compliant ride -- but only if the revised geometry and the 6112 shocks would allow for it. Like you, I don't have any information on how much stiffer the 6112s are than stock.

It seems like a stiffer ride is just part of the deal when doing a lift of >2". Most people seem to like the stiffness; some don't. In all the lift threads I've read, if anyone has retained stock ride compliance after doing a >2" lift, I haven't seen it -- seems like most report their ride quality as "better" because they like the tauter handling and reduced nose dive.

If it's any consolation, my Toytec Ultimates set at around 2" of lift are noticeably stiffer than stock, too.

In any event, I'd say the increased stiffness is due to three factors: 1) geometry; 2) spring rate; 3) shock valving. Which of those factors contributes the most, and how exactly they interrelate, is outside my knowledge thus far, but I'm pretty sure that "preload" isn't itself a factor

So here's an update... and I now feel bad that I may have given some false feedback on my bilstein 6112/5160 set-up.

After a bit of highway driving I noticed the truck felt ok. Nothing great. Still really really stiff. Any ripple in the pavement was felt in the seat and steering wheel. I'm currently running 275/75/17's that I swapped along with the wheels from my last 4runner. I was running those at 34-36psi on the road, and have never had an issue (30,000km on them so far). After I installed the suspension I and took it back to the shop for a wheel alignment (5km away). My first driving impression was after the wheel alignment, which I instantly noticed was stiffer. I didn't notice that the work invoice also mentioned that they topped off the pressure to 45psi. I noticed this on the weekend when I was checking some other things... dropped the pressure back down to 34psi. Huge difference. Much much nicer to drive. The way it should be.

Now I just need to order the new rear springs to bring the back end down to where I want it.

 

[jayhat]

So are the 6112s, as configured from the factory, good for additional weight in the front? I have a Gobi rack, sliders, will have an SSO slimline bumper soon. Possibly a dual battery at some point soon'ish. Maybe a winch one day. I've heard they should be good for additional weight but they dont really make that clear (to me anyway) in the specs. I like that OME springs say - use this spring for this many additional pounds, this heavy duty spring for this many pounds, etc etc etc.

 

[EddieV4runnin]

What I ended up doing was setting both fronts at the 7th notch. That leveled things out... but, the preload is insane for a 2.5" lift. You won't be able to do this without a really good spring compressor. If you go this route, I would take the stock front struts assemblies off, remove the stock top plate that's required for the bilstein installation, take it into any garage and have them assemble.

I'm currently looking at Dobinson's front springs to replace the ones supplied with the bilstein 6112's. They are a 2" longer and if that means I can run less of a preload, it would be great.

But honestly take a look at the toytec set up, it's comparable price, but you don't get the oversized strut. I really regret the set up I'm running right now. The front looks great with a 2.5" lift, but the ride is just that bad.

As for the rear, I installed the 5160's and they seem great. I'm looking for options on rear springs though. The sway-a-way 1.5" springs resulted in a 2" lift. The 1.5" lift is based on a 3rd row rear seat (or at least that's my thought process on it). Again, Dobinson's will be coming out with a 1" rear spring that I'm eyeing up for the end of the summer. It all depends on how much additional weight the rack adds and if the springs settle. I want the near level look. Although I do notice a much nicer ride overall with a the truck loaded.

As for the KDSS lean, it doesn't exist at stock. But the bilstein instructions says to have the passenger side 1 notch lower. This is only for non-kdss equipped vehicles. The intent of this is to compensate for the extra weight that is on the drivers side (battery and gas tank). If you do this, you only amplify the lean. If you install at equal settings, and there is still a lean, Toytec has a 1/4 spacer that you could install on the passenger side front, or OME has a 10mm spacer for the rear.

Hope that helps some.

What's the length of the 6112 springs??

 

[onepremiere]

What I ended up doing was setting both fronts at the 7th notch. That leveled things out... but, the preload is insane for a 2.5" lift. You won't be able to do this without a really good spring compressor. If you go this route, I would take the stock front struts assemblies off, remove the stock top plate that's required for the bilstein installation, take it into any garage and have them assemble.

I'm currently looking at Dobinson's front springs to replace the ones supplied with the bilstein 6112's. They are a 2" longer and if that means I can run less of a preload, it would be great.

But honestly take a look at the toytec set up, it's comparable price, but you don't get the oversized strut. I really regret the set up I'm running right now. The front looks great with a 2.5" lift, but the ride is just that bad.

As for the rear, I installed the 5160's and they seem great. I'm looking for options on rear springs though. The sway-a-way 1.5" springs resulted in a 2" lift. The 1.5" lift is based on a 3rd row rear seat (or at least that's my thought process on it). Again, Dobinson's will be coming out with a 1" rear spring that I'm eyeing up for the end of the summer. It all depends on how much additional weight the rack adds and if the springs settle. I want the near level look. Although I do notice a much nicer ride overall with a the truck loaded.

As for the KDSS lean, it doesn't exist at stock. But the bilstein instructions says to have the passenger side 1 notch lower. This is only for non-kdss equipped vehicles. The intent of this is to compensate for the extra weight that is on the drivers side (battery and gas tank). If you do this, you only amplify the lean. If you install at equal settings, and there is still a lean, Toytec has a 1/4 spacer that you could install on the passenger side front, or OME has a 10mm spacer for the rear.

Hope that helps some.

Could you elaborate on the ride quality at 2.5"? The general consensus I've read is the 6112 is about the best ride quality short of going to an adjustable coilover. I've lifted enough Toyota trucks to know where they are happiest, and which set-ups are best. The 4Runner however has truly tested my knowledge. I've torn down the front end 5 times now, and I only have 1700 miles trying to achieve what I consider a comfortable ride. The 6112 is my last option, so I am curious what it is about the ride you do not like?

 

[Sauce839]

Could you elaborate on the ride quality at 2.5"? The general consensus I've read is the 6112 is about the best ride quality short of going to an adjustable coilover. I've lifted enough Toyota trucks to know where they are happiest, and which set-ups are best. The 4Runner however has truly tested my knowledge. I've torn down the front end 5 times now, and I only have 1700 miles trying to achieve what I consider a comfortable ride. The 6112 is my last option, so I am curious what it is about the ride you do not like?

At first I thought it was too stiff, and started looking for other options. But after I found that when the truck was taken in for an alignment, the mechanic had over inflated the tires. I've now dropped them down to 40psi for the road, and the ride is much better.

 

[onepremiere]

At first I thought it was too stiff, and started looking for other options. But after I found that when the truck was taken in for an alignment, the mechanic had over inflated the tires. I've now dropped them down to 40psi for the road, and the ride is much better.

Appreciate that! That will definitely make the ride uncomfortable. 6112 it is.

Cheers!

 

[TotalAutomotiveLV]

Bilstein 6112 and 5160's are a great set-up.

If you are looking at doing a 2.5-3" lift in the rear, ICON works
well and pairs nicely with the 6112's.

We have some specials going on for the...

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[cityblues]

"KDSS lean"

I found this video regarding the KDSS lean and how to simply fix it. This was on a LC and may apply to our 4RTs:

https://www.youtube.com/watch?v=xtURdW66WM4

 

[rkwfxd]

I found this video regarding the KDSS lean and how to simply fix it. This was on a LC and may apply to our 4RTs:

https://www.youtube.com/watch?v=xtURdW66WM4

That's pretty slick. Mine is only two weeks and 187 miles old so I have zero lean. Looking to lift but don't want to end up with a lean.

 

[rrsuby25rs]

Bilsten 6112 circlip settings??

I own a 2011 Toyota 4Runner Limited 4x4 w/ X-REAS and I do NOT have KDSS. Stock rims and tire sizes at P245/60R20. As of right now, I have oil leaking out of all 4 stock shocks/struts and because of it having the X-REAS system, the dealer wants roughly $4,000 to replace all 4. That's not happening. What I'd like to do is just remove the X-REAS system and replace with aftermarket shocks/struts/springs. I know it can be done and I'm looking at purchasing everything I need and either doing the install myself or taking it somewhere to do. Either way, I'd like to purchase all the parts together from one spot.

I have been on this forum reading TONS of forum posts on this topic and I believe I have it narrowed down. I want to give my rig a slight increase and height while keeping this down to a lower cost overall compared to replacing everything stock. I'm not looking to lift more than about 1.5", am going to be keeping stock rims/tires for now (but would like a more wider look to bring out tires to wheel well at a later time) and overall, I'm after a more level "look" and stance of the 4Runner. This is a daily commuter on road and will never be used off-road except for a yearly trip riding on the beach at OBX.

All of that said, I have it narrowed down to the following:

1. Bilstein 6112's up Front
2. Bilstein 5160's in Rear
3. Wheeler's T13 Rear Springs (1.5")
4. Billet Reservoir Clamps for Bilstein 5160's (x2)

My question for you guys before I order is around the 6112 circlip settings and my overall lift height max that I'm after of about 1.5" with a leveled look overall. If I'm getting the 1.5" springs in rear, what circlip settings should I set for both Driver and Passenger side of the Bilstein 6112's? From looking at the install diagram of the 6112's, it looks like I would need a Drivers side circlip set at #4 and Passenger side circlip at #3 for a lift of 1.5" up front. That combined with the 1.5" spring in rear would give me 1.5" overall, correct? Would that give me a leveled look as well?

Thanks for the assistance all!

 

[Judd94]

Here’s the updated KDSS and Non KDSS settings