Bilstein 8112/8100 - Cross Post

Update TL;DR: Shims are NOT recommended for extended-length aftermarket shocks. Additional lift over stock reduces down travel. Thanks to everyone who helped me understand this and Toyota IFS!

I originally posted this in the 5th Gen forum, but I figured Suspension would be more appropriate:

I've searched forums and Google extensively and have yet to find specific information on what I intend to do, so I started this thread.

My 2024 4Runner came brand new from the dealer with 2021 TRD PRO wheels, 285/70 Mickey Thompson Baja Boss AT tires, and a 3" Ready-Lift spacer kit (one-and-one-half inches on top of the stock coilover). I love the look, height, wheels, and tires, but I did not want a spacer lift, and I ordered Bilstein 8112 coilovers and 8100 smooth body shocks (no bypass) with OME 2895 rear springs. I am also installing a Dr. KDSS bolt-on panhard bar relocation kit, Dobinsons UCAs, Dobinsons adjustable rear sway bar links, an Icon front sway bar relocation bracket, and extended brake lines.

After too much research and watching several great videos from Tinkerer's Adventure, I decided to add a 1/2" Ekstrom shim (two 1/4" shims/side) to the coilovers. I'm looking for ~3" of lift in the front, but I do not want to max out the preload, thus the shim. If I understand all this correctly, the 1/2" Ekstrom shim will equate to ~1" of lift, allowing me to run the coilover at ~2", helping to keep my down-travel intact. The OME rear springs are rated at 2-2.5", which is fine since I am looking for more factory rake than leveling.

Tinkerer's Adventure - Everything about Toyota IFS, Part I

Tinkerer's Adventure - Everything about Toyota IFS, Part II

I am not running aftermarket bumpers or carrying anything on the roof, so I ordered the normal spring for the back. I will install Wescott Design rock sliders, adding ~100 pounds, but that is the only additional weight.

Am I on the right track here? I was surprised to find very little higher-level information on Bilstein 8112/8100 installs and almost no information on the 8100 smooth body shock. Everything I found on the 8100 was for the bypass shock, which was way more than I needed or wanted to spend. This configuration wasn't cheap, but the bypass rear shocks would add ~$1200 to my build, pushing it over the edge. Not to mention, I doubt I would ever be tinkering with rebound and compression settings for the driving I do.

Thanks!

 

So you don't want a spacer lift so you're going to do coilovers with a small spacer lift (because the two 1/4" shims are nothing more than a 1" spacer lift...)?

I mean, you do you but if it were me, I'd look for proper shocks and coils to do it without being preloaded to the max and without a spacer. I'd also check the travel of those rear shocks and make sure they are going to have some travel left with those coils.

 

You don't seem to grasp my question, but thanks for chiming in. There are many shock options for a 4Runner that are not long travel, and offer a range of lift heights. By design, the higher the lift, the more preload. The higher the preload and lift, the less down travel available. If you watch the second link I included, Kai explains the different up and down travel at different lift heights and the impact of more preload. "I'd look for proper shocks and coils to do it without being preloaded to the max and without a spacer." It sounds great, but it is all a matter of give and take. I'm not building a trophy truck, and the Bilstein 8112/8100 are considered some of the better options for a 4Runner. But whether you choose Bilstein, Fox, King, etc., the preload/down travel equation is all the same. Things might change with long travel and replacing the lower control arms, but that is not what I am doing. One of my goals is 3" of lift, and a way of getting there without using maximum preload is using shims.

Does anyone grasp the question and have real-world experience?

 

Below is what I was suggesting. Shocks designed for 2-3.5" of lift. Their selection page seems pretty comprehensive and there is no mention of lower control arms being needed. It would be worth at least having a conversation with @Crikeymike at Exitoffroad. If it is not what you're looking for, you're out a few minutes of time. But it might be exactly what you are looking for.



Or, just do what you posted but don't ask for advice and then just dismiss anything that differs from your plan.

 

Thanks for listing an example. I am not dismissing anything that differs from my plan, but I am looking for anyone with experience with the approach I learned about through research. Here is another video that briefly addresses shims and goes into some detail about extended travel shocks.

Truth About Extended Travel Coilovers for Toyotas

As Kai mentions in the video, most manufacturers are vague about shock length, travel, and other aspects of their shocks. That vagueness is what prompted me to create this thread.

I was unaware that the Dobinsons used taller coil seats, so thank you for sharing that. But wouldn't that be the same as using less preload and adding shims? Albeit, a taller coil seat is a more elegant solution with fewer parts.

 

Tundra Talk - Post on Shims

 

If you lift your truck 3" then you've severely handicapped your down travel because of the geometry of IFS. Kai talks about this in the videos you posted. More specifically, you will probably be slapping your UCA against the coil......so there is no need to try and extend or try and save your travel with shims. You'll just be maxing out elsewhere.

Why not just keep it at the recommended height that Bilstein states with the shocks? That recommendation is there for a reason.

Or you could get extended UCA's and LCA's. That would afford you more lift and travel.

 

Bilstein quotes the ride height as adjustable from zero to 3.8", so nothing is against Bilstein's recommendations. Kai also specifically mentions 2" of ride height from the coilover as the sweet spot for down travel and suggests a shim as a good option for additional height. My thoughts on using a shim came directly from Kai's video. I did not make this up from thin air.

I hope to find someone with real-world experience with this setup, like the discussion in the Tundra Talk thread linked above. I am using a Dobinsons UCA, and in my research and the experience of others shared in many places, there should be no issues with the UCA binding against the coil. I am planning to use 2" of lift from the adjustable coilover and gain the next inch from the shims. Candidly, I didn't think this would become such a contentious issue, considering all of the 4Runners out there lifted 3" and the information supporting my plan in the provided links. I am happy to agree to disagree, but as I asked Mainerunr, isn't a shim the same as a taller coil seat?

 

I had a great conversation with an Ekstrom Design technician, who confirmed that up to 1/2" of shims is the sweet spot to balance travel without adding unnecessary preload to the coilover. Ekstrom does a lot of work with King, Icon, etc., and said that King, in particular, recommends using 1/2" of shims in many of their installations. I'm not surprised that Shock Surplus suggested using the Bilsteins without shims, but Ekstrom provided considerably more detail and was happy to answer my questions. Here is another link to an install taking a 4Runner up to 4" of lift using Ekstrom Shims:

Ekstrom Shim - 4"-4.5" Lift on Gen 5 4Runner

Today, I emailed Ian at Wheel Every Weekend asking about using 1/2" shims with Bilstein 8112's. I will post the response when I hear back.

There will always be opposing views since everyone has opinions about brands, setup, and what is optimal for Toyota IFS. Hopefully, the information in this thread will be helpful for someone trying to decide on suspension in the future. This thread on Tundra Talk got deeper into the shim vs. no shim discussion with real-world experience.

Tundra Talk - To Shim or Not to Shim

I know many people respect Kai at Tinkerer's Adventure, and I suggest watching his Part II video on Toyota IFS to hear his opinions about shims/spacers. Again, this is up to a half-inch, not the ReadyLift style one-and-a-half-inch spacer kits, like the one that was dealer-installed on my brand new 4Runner. Kai also talks about using his stock UCA's with an extended travel shock and not contacting the coil. Two of the better videos I found regarding UCA's were from Kai.

Tinkerer's Adventure - UCA's True Functions and Misconceptions | Toyota Aftermarket UCA Part 1

Tinkerer's Adventure - Which UCA is Best for You? Toyota Aftermarket UCA Part 2

After several hours of research over several days, the links I included in this thread helped me the most. Whichever way anyone chooses to go with suspension, the included links should be helpful.

 

Articles – AccuTune Off-Road (accutuneoffroad.com)

 

I talked to King this morning, and they adamantly opposed using a shim with their shock. I'd imagine Bilstein will say the same thing, and I will post here when I find out definitively. @iamincrediboy, thanks for the Accutune article link.

 

I am waiting for a response from Bilstein and WEW about shims, but from a purely mechanical perspective, I still can't understand why shims would be inherently bad. If a particular coilover has a range of lift height available, say 0" to 3", as the coil seat is raised to increase lift, the coilover is, in essence, getting longer. If I set a coilover at 2" of lift height, and there is an extra 1/2" attainable that I take up with a shim, the overall length of the coilover would be the same as setting it to maximum lift. The only difference would be the amount of preload on the spring. Using a stock coilover and adding a ReadyLift 3" lift spacer, I can see the possibility of overdriving the coilover and bending the piston shaft. But, even in that scenario, taller bump stops should alleviate the issue. In the Tacoma threads I have read, a 2" lift and 1/2" shim is pretty common, with many users reporting high mileage on those setups without issue.

A shock cranked to maximum lift height and then shimmed does seem like it could cause problems without taking other measures. However, it doesn't seem to be an issue as a tool to achieve a particular lift height without adding extra preload. What am I missing? I am just trying to understand the mechanical aspects of this scenario.

 

Have you considered what the control arms are doing in the various scenarios you describe? Or how those scenarios affect the control arms' available range of motion?

 

I have taken the UCAs into consideration, and am using Dobinson’s. All of the parts I am using have been used in 4Runners for a long time without any issues I could find. I’ve talked to several suspension companies and installers now and most have said that what I am doing is within accepted standards. There are a range of opinions on shims, but plenty of experienced installers have had good long-term success.

 

Let me be more explicit. Have you calculated what the control arm angles and ranges of motion are for the different scenarios and compared the values? Has anyone that you talked to given numbers for the different scenarios? What are the differences?

 

No, I haven't calculated any of that, nor has anyone I spoke to. What exactly would I be looking for? All of the coilovers I considered had a lift range of ~0" - 3.5", and most recommended using aftermarket UCA's for Camber and Caster when aligning the vehicle after installation. The most in-depth information I found was the Tinkerer's Adventure UCA videos.

Do you see a potential issue with the UCA? It doesn't seem like this is outside the accepted parameters.

 

I haven't received replies to my suspension questions from different vendors or Bilstein, but I did get some information on the 8112/8100 dimensions compared to stock.

Rear 8100: Collapsed Length (IN)14.94, Extended Length (IN)23.48
Stock height - 4600: Bilstein Collapsed Length (IN)17.11, Extended Length (IN)21.92

Front 8112 - 1.5-3" Front Lift: Collapsed Length (IN)17.99, Extended Length (IN)22.80
Stock height - 4600: Collapsed Length (IN)17.11, Extended Length (IN)21.92

Based on this and all of the information I have gathered on this forum and elsewhere, I will not use the Ekstrom shims. However, I am still seeking feedback about running the 8112 at 3" of lift.

 

I'm gonna go ahead and retract my original statement (while leaving the evidence that I've changed my mind). After watching a few of Tinkerer's videos that I had not seen (and not any of the ones linked), it seems there is room for about an inch more extension and maybe a small spacer is a good way to use that (as long as it will not result in damaging the shock on compression).

Of course, now I'm looking for a shock with about an inch more extended length than stock...or considering a half inch lift spacer plus a shock with a 1.5" lift coil...goal of 2" lift while losing as little droop as possible.

 

The correct way to lift is preload or stiffer/longer springs, not shims. Maximum shock length is limited by the length of the shock while compressed and performance is typically a function of the travel that can be segmented into the different zones. Longer travel gives better control. Shims typically cause high end shocks to bottom out and you can correct with bumpstops, but all that is doing is leaving shock extension on the table while further limiting your total travel.

This is race truck logic where you control shock mount locations but the logic is still correct. It's not perfect on an OE setup where you don't control geometry so it's not that it won't work for you, it's just the wrong way to approach a $4k suspension. You're buying a flagship product and intentionally limiting what it can do.

 

It was the additional length and travel of the 8112 that convinced me to ditch the shims. I'm having everything installed a week from today, and I will update the post then. 8112s are about an inch longer than stock.

 

I think you missed my post explaining that I was NOT going to use shims.

 

I frankly don't give a shit what you do. You asked why shims were inherently bad and I answered. Your truck your call and any "you" in the post was just a universal statement.

 

I bet you are fun at parties. Have a great night.

 

Nah I'm mostly an introvert who cosplays as an extrovert from time to time. You asked the question and just because you changed your mind doesn't mean that gap was filled for you or anyone else who may come across this in the future.

 

The minimum lift for the 8112 is 1.5", and the coilover is .88" longer than stock, so what would the ideal lift height be to maintain a proper up/down travel ratio? Would 2.5", which matches the OME 2895 rear spring, work? I am not opposed to a different rear spring lift, and I don't care if I don't achieve 3" of front lift if doing so will sacrifice suspension quality. I am on Forest Service roads a lot, washboard roads, and lots of embedded rock that is pretty rough. I am not driving extremely difficult terrain, but I need to access rough, remote roads way off the beaten path for my job. I am not adding weight to the vehicle. I know @Lost Woods is a former Master SAE Mechanic who might know the answer. I said I was trying to achieve a 3" lift, but a well-designed system is more important than actual height. I also want clearance for the 285/70 Mickey Thompson Baja Boss AT tires since those came on the vehicle. I'm just trying to learn, and after several hours of research, I still need help finding definitive answers. I did find a phone number for Bilstein and plan to call them tomorrow. Thanks!

This was an interesting article:

Coilovers - Installing and Setting Height Correctly

 

Factory downtravel is something like 4-4.5" so subtract your lift from that - it's a 1:1 swap between up and down since lifting only changes ride height, not travel. The limit is the upper ball joint so an aftermarket UCA with a ball joint that gives more articulation will give you a bit extra... I want to say in my Taco days like .75" was possible so a 2.5" lift would still likely give around 2.5" down. I personally don't like less than that with similar driving as you and more is better for traction. I don't know exactly where things line up because I'm still waiting on my 6112s and I'm starting at 1.9" with the 1-1.5" spring in the rear.

Any off-the-shelf strut will be sized correctly for stock or stock+UCA geometry in regards to length so unless you're doing some custom thing, trust them. The benefit you have with the 8112s is that they're totally adjustable and you can dial in small increments fairly easily for ride height. If you have threads and you're not stacking coils, you can adjust higher. If they say you can get 1.5" to 3", you can crank right up to 3" without worry. If you want less, ask for a lighter spring. If you want more or are carrying 150# like a bumper/winch, go heavier. You control the ride height as you need and the ride quality isn't going to change much to preload as much as it does to different springs.

Suspensions are never an exact science and you'll go through trial and error to dial it in. Start at the 2.0-2.5" setting and either go for a shakedown run or just measure if that's enough droop measuring hub center to a fixed spot on the fender at ride height and jacked up with the sway bar disconnected. Don't measure down because tire squish messes up numbers. If you need to adjust, you can remove the strut, use cheap compressors (it's fine with the hat in place just watch your fingers) to relieve the tension on the spring and crank in the adjustment.

If you haven't ordered them, I'd forego the rear springs for some spacers for now to dial in your fronts, then weigh your axles and reach out to someone who has done the math to order an appropriate spring. The spacer issue doesn't apply in the rear so you can use them to balance out your heights too. It's an added cost but so is buying the wrong rear springs and most people I know have done it.

 

My installer ordered the springs, but I am happy to pay him the restocking fee and order something else. I originally ordered the 2-2.5" OME spring because I planned to lift 3" up front. But, before my installer made that recommendation, I was considering the Bilstein 1.5" spring. A 2.5" lift in front with 1.5" in the rear seems like it would give me the rake I am looking for.

You said the lift height to down travel loss is 1:1 but does that mean an extended shock like the Bilstein at normal ride height has 1/2" more up and down travel? Thanks.

 

Your wheel travel is defined by the arms so lift won't directly change that. If you start with 4.5" up and down for 9" of travel, adding a 3" lift means you now have 1.5" down and 7.5" up (barring things like bumpstops to prevent tire contact). The strut length required in this case is no different than stock because the wheel makes the same arc but you do often find aftermarket struts with an extra little bit to compensate for the UCAs that do give a little more droop. The lift heights on shocks are partly because they know above 2" you're looking at UCAs but also where the valving for each zone kicks in so a shock for a 1.5" to 3.5" lift will have the middle cruising zone sit a bit more towards the compression side and the compression zone will be more aggressive since it has less space. If you lift a neutral shock you can often find yourself riding too deep in the compression zone and it gives a harsh ride. This is why I 100% recommend buying high end stuff from Accutune and having them do the valving to match your setup.

 

I had my oil changed today at 2000 miles, and my mechanic mentioned I have a diff drop. The dealer that installed the spacer lift didn't give me a spec sheet, so that was news to me. If I knew then what I know now, I might have purchased a different 4Runner and done all the upgrades myself, but it isn't that big of a deal.

I’m also installing DuroBump stops, with the 4.25” in the rear. I might just run with 3”/F and the 2”/R springs to start and see how it rides. I called Bilstein this morning and am in line for a call back, but that was four hours ago, so I'm not holding my breath.

 

This is what I was getting at with the geometry questions. I thought looking for oneself at the geometry of the main elements would be more enlightening to anyone inundated with raw assertions.