Wunderladen Racing; Rear Toe Arms

Why are rear toe arms something that you need? Because from the factory there is no independent rear toe adjustment so what you get is what you’re stuck with after you’ve set camber, if you have camber adjustability. If you don’t have camber adjustability (i.e., stock camber arms) then your toe can be adjusted slightly, but you then sacrifice even camber side to side.

Hold on… Before all the Facebook internet mechanics start to lose their shit and argue with me. Let me further explain.

Technically the toe is somewhat adjustable on our cars from the factory by way of the rear lower control arms. However, because it is not an independent way of adjusting toe this is not the most desired way because it can affect other alignment settings like camber and can throw off suspension geometry. Adjusting the toe via the lower control arm can also put excess preload/stress on suspension parts. Under normal boring driving conditions, you won’t notice any of these downsides. So, if you only plan on taking your FK8 to cars and coffee, then you can stop reading now. For the rest of you that actually track your car, or desire to learn. Please, carry on.

When manufacturing cars, in order to make the assembly line more efficient suspension/brakes and subframes are assembled off the car and then installed in large pieces. To help speed up assembly, subframe bolt hole tolerances aren’t very precise. Because of this, each car rolls off the assembly line with the subframe in slightly different positions. This means all suspension arms and mounting points cannot be fixed with no adjustability. Otherwise, alignments would be off from factory. Therefore, the little toe adjustability through the rear lower control arms is only there so Honda can ensure that cars roll off the assembly line with the wheels pointing in the right direction. From the factory, this is the ONLY adjustable part of our rear suspension.

Where the lower control arm bolts to the subframe, the subframe is slotted, and an eccentric bolt/washer combo is used to ever so slightly adjust the toe and ensure the tires are pointed in the correct direction. But as mentioned above, adjusting it this way can throw off other measurements and or put excess preload/stress on the suspension parts. Again, this is fine for the average consumer that buys a car just to commute, never modifies it, takes it to Honda for an alignment, and likely will never need any more adjustment other than the small amount given by the rear lower control arm.

Regardless, sometimes that one (per side) factory adjustment isn’t enough to get your toe back into spec without having a stupid amount of rear negative camber from lowering your car. Or sometimes it doesn’t allow you to achieve the amount adjustment you’re looking for when trying to get your car to behave a certain way on track.

Because our cars have a multi-link rear suspension, when you lower them, they gain quite a lot of negative camber. Because of this. Most people will buy a rear camber kit when lowering their cars to combat excessive tire wear and to ensure they have less rear negative camber than front. After installing a rear upper camber kit. This now gives us two points of suspension adjustment (per side) and this is why most people can generally get their toe and camber set to “factory” spec simultaneously without the need for rear toe arms.

See the pictures below from when I installed SPC rear upper camber arms.

Rear adjustable toe arms or (links) are designed to allow complete control over the toe angle at the rear wheels. Altering the vehicle toe angle may be desired due to user preference. Or, it may be required due to changes in the suspension geometry that occur when the vehicle is lowered with springs or coilovers.

It’s also preferred to upgrade because the OEM bushings and stamped steel arms have a lot of flex and can cause the alignment to change when great forces are applied. This can result in less confidence while putting your car through its paces on track.

Below are the real, hard-hitting facts.

Installing rear toe arms on an FK8 can offer several benefits, including:

  • Improved Handling and Stability: Rear toe arms allow for finer adjustments to the rear toe angle, which affects the vehicle’s handling characteristics. By fine-tuning the rear toe, you can enhance the car’s stability, cornering ability, and overall handling performance.
  • Enhanced Traction: Proper rear toe alignment ensures that the rear tires maintain optimal contact with the road surface. This improved contact patch translates to better traction during acceleration, braking, and cornering, resulting in improved overall performance and reduced tire wear.
  • Adjustability for Performance Tuning: Rear toe arms provide adjustability, allowing you to dial in the rear toe angle to suit your driving preferences or specific performance modifications. This adjustability is particularly beneficial for enthusiasts who have made suspension upgrades, installed wider tires, or lowered their vehicle’s ride height.
  • Correcting Uneven Tire Wear: Misaligned toe angles can cause uneven tire wear, with the inner or outer edges of the tires wearing more rapidly than the rest of the tread. By installing rear toe arms and properly aligning the rear toe, you can mitigate uneven tire wear and extend the lifespan of your tires.
  • Customizing Vehicle Dynamics: Rear toe arms provide an opportunity to customize your vehicle’s dynamics. Depending on your preferences, you can adjust the rear toe angle to achieve understeer or oversteer characteristics, tailoring the handling balance of the car to your liking. This is a huge benefit for someone who is at the track frequently and is trying to extract 10ths of seconds. For the more advanced driver, this also means you can more easily dial in toe settings for specific tracks.
  • Increased Suspension Rigidity: Aftermarket rear toe arms are often built with stronger and stiffer materials compared to the stock components. This increased rigidity helps to minimize flex and improve the overall responsiveness of the suspension system. Thus, resulting in better feedback and control.
  • Track Performance Enhancement: If you plan to take your FK8 to the track, installing rear toe arms can be particularly advantageous. Fine-tuning the rear toe can optimize the car’s cornering stability, allowing you to maintain better control and extract more performance during high-speed turns and aggressive driving maneuvers.

It’s important to note that installing rear toe arms should be accompanied by a proper alignment. This ensures the suspension geometry is correctly set up for your specific needs and driving style.

What all that means is. If you’re at all serious about tracking and want to maximize your car’s performance and potential. Then you need rear toe arms to unlock more precise suspension adjustability. It’s like one of those things you didn’t know you needed until you installed it. Then, you immediately wonder why it took you so long to get it.

But… and this is a BIG BUT! Let it be known that you can still be fast without having adjustable rear toe arms. Hell, I was able to achieve my first sub 2 at Buttonwillow with only adjustable upper rear camber arms. It’s best to not fixate on what can be done without rear toe arms. But rather, on how much better the car is with rear toe arms. PLUS, your alignment guy will thank you for all the points of adjustability.

Now that you are thoroughly educated in rear suspension and alignments. Let’s get on to the pictures and installation process. Plus, why I purchased Wunderladen Racing arms over other companies out there.

Below you can see, I purchased Wunderladen Racing rear toe arms. Yes, there are a few other companies out there that make a decent adjustable rear toe arm. But as I mentioned in last week’s post (FK8 RMM SHOOTOUT), Wunderladen Racing is a company for enthusiasts by enthusiasts. They are a small American company that designs and produces all of its products right here in the good ol’ U.S.ofA. Not only do they specialize in making track performance products. They also have their own 10th gen civic that they regularly track and use as a test mule for all products they design. Because of these reasons and more, I’m happy to support companies like them.

If you’re interested in reading last week’s post you can click the link below.

On to the Step by step install process:

Start like we always do. First, invite your dog to come hang with you.

Your dog is your number-one defense against creepers, lurkers, and nosey neighbors.

Second: begin jacking up the rear of the car from the specified rear jacking point (as seen below)

If you have a Mugen lip or any other aftermarket lip. Be careful not to jack the rear end up too high otherwise your front lip will scrape on the ground. If you don’t have a Mugen or any other aftermarket front lip, then fuck it… Let that OEM front lip scrape all you want. J/K, do whatever you want. Just keep in mind when jacking up the rear end only, it will most likely cause the front to come in contact with the ground.

I literally do few jack pumps just to get the rear tires off the ground. Then run up to check the front lip. Then run back and do another jack pump. Then run back to check the lip, and so on, until it’s this close (see picture below). Sure would be nice to have a buddy hanging out with me in the garage (other than my dog. This way, I wouldn’t close all my move rings by just jacking the car up.

Next, once the rear is jacked up and your lip isn’t scraping. Place jack stands under the rear of the car, on the thicker pinched areas under the car (as seen below). Then remove both wheels.

Here you can see the OEM rear arm that we will be removing and replacing with the Wunderladen Racing rear toe arm. To me, the OEM arm somewhat resembles a cartoon’s representation of a dog bone… Am I crazy?

Here is where you will unbolt it from the subframe.

One 17mm bolt

You will only need a socket on one side. Because as you can see below the threaded part is fixed to the subframe.

And here is where it will be unbolted from the knuckle/hub.

For the knuckle/hub side. You will need a 17mm wrench/socket on both sides because the nut is not fixed to the knuckle/hub.

Here is another perspective just so you are clear about what arm is being removed and replaced. (I’m pointing to it)

17mm wrench goes here.

17mm socket goes here.

Tools in place. Use the wrench to initially break the nut loose, then the ratchet to quickly loosen and extract the bolt.

Once the nut is removed, the bolt can begin to slide out.

If your car is on aftermarket springs, then there shouldn’t be much tension on the bolt. It should easily slide out. If you have stock springs, then just place a jack under the factory lower control arm (that you are removing). Then, slightly apply upward pressure to neutralize the tension on the knuckle/hub and lower arm.

With the knuckle/hub bolt removed, it’s now time to remove the 17mm bolt that goes through the subframe.

Once the bolt is completely unthreaded it should look like the below picture.

On the driver’s side. You’ll notice that conveniently, Honda has made a small relief in the gas tank to allow the bolt to be completely removed. Bless them for thinking of us and not going all European car engineering on us.

Here is what it looks like once the knuckle/hub bolt has been removed.

Then, once the subframe bolt has been removed the arm will easily come out.

Pay close attention when going to install the new arms because each side is a different thickness. As you can see below one side is 51mm.

and the other side is 46mm. Honestly, you would have to be pretty daft to mess it up since technically one side won’t even fit. But I’m sure someone might try and force it. So, I’m just bringing it to your attention so you are aware.

Here you can see the OEM arm compared to the Wunderladen Racing arm. Notice that the Wunderladen arm length needs to be extended slightly. This will ensure your alignment is at least somewhat close to what it what previously. And, will enable you to make it to the alignment shop without any “extra” excitement on the drive there.

To help get the new arms relatively close to the length of the OEM arms. I insert one of the OEM bolts through the OEM arm and into the Wunderladen Racing one.

Below you can see just how far off I am.

Below you can see that I have inserted the other OEM bolt on the opposite end.

Next, I take my left hand and hold the rod end, so it won’t move. Then, with my right hand, I twist the center hex part of the arm. Because one side is a left-handed thread (reverse thread). The twisting of the black center part will cause both ends to evenly extend. It’s important to ensure both rod ends are threaded evenly into the hex part of the arm. This guarantees there will be enough rod end thread, threaded into the arm. This way, you won’t have any issues with fatigue or thread failure. This guidance is not specific to the Wunderladen Racing arms. This logic should be applied to ANY aftermarket part that is threaded on both ends.

Below, you can see how I’m closer to the desired length. I probably just need a few more twists to get the bolt to line up perfectly.

BOOM! Just a few more twists and I’m able to get the new arm to be damn near the same length as the OEM arm I just removed. You can also see how there is now thread noticeable on the rod end and it’s an even amount on both sides. This is because I had one end of the rod end locked in with the bolt. The other end was unable to move because I was holding it with my hand while I twisted the center porting of the arm. Make sure you have the spherical as close to perpendicular as possible when compared to the black hex arm part to ensure the measurement is as accurate as possible. You just don’t want the spherical to be twisted in any way.

Now, thread on the jam nuts until they make contact with the black hex part of the arm. You should just “snug” the jam nuts down ensuring there is no movement or unthreading. If left loose, there is potential to change the overall length you have set them to while installing on the car. Once fully installed on the car, you can then fully lock the jam nuts down.

Remember, the side with the groves machined into them are reverse threads. And another cool thing that Wunderladen Racing does is. Machine grooves the spacers so you know that you have them on the correct side.

And, you can see on this side there are NO grooves.

11mm of thread on one side.

and 11mm on the other.

Non-grooved side goes into the subframe.

The grooved side goes into the knuckle/hub side.

Tighten up your bolts. I don’t torque them because I just make them “pretty tight”. But here are the torque specs if you want to torque them. 60 lb/ft for the nut and bolt on the knuckle/hub.

And 56 lb/ft for the bolt that goes through the subframe.

I’m a bit OCD so I try to make sure my rod end is lined up perfectly when installed. This also ensures that there is a full range of motion on the spherical at ride height or under full compression of the suspension.

Once completely installed, don’t forget to cinch down the jam nuts to a reasonable amount of tightness. There are no toque specs, but maybe a good grunt during the tightening will ensure its tight enough.

Fully installed.

Below is a close-up of the rod end and that it utilizes a self-lubricating PTFE liner, so they are maintenance-free and live a longer life than non-lined rod ends. 

And here it is installed on the other side too. My install process only shows the driver side install, however, its the same process for the passenger side.

All the tools that were necessary.

  • Jack and jack stands to raise and secure the car off the ground.
  • 19mm socket to remove lugs (I have spoon ones) OEM lugs are 21mm.
  • Breaker bar to loosen the lug nuts.
  • Crescent wrench to use in holding the center black section of the arm while tightening the jam/lock nuts of the arms. (after installed on the car).
  • 24mm wrench to tighten the jam/lock nuts on the arms.
  • 17mm wrench to use on the nut of the bolt on the knuckle/hub side.
  • 17mm socket to use on both bolts (subframe and knuckle/hub).
  • Electric ratchet (optional) you can just use an old-fashioned manual one too.
  • Calipers (optional/not necessary) I only used them the help illustrate the different sizes of the bushings at each end of the arm and the even amount of threads I had showing.

Overall, this install is maybe a 2-3 difficulty level on a scale of 1-10. It’s really as easy as:

  • Jacking up the rear of your car, placing it on jack stands, and removing the rear wheels.
  • Unbolting both sides of the OEM lower arm and removing it.
  • Aligning the Wunderladen Racing arm to match the same length as the OEM one.
  • Installing the new arm by reusing the OEM bolts and nuts to secure the new arm.
  • Ensure the jam/lock nuts on the Wunderladen Racing arm are cinched down.
  • Putting the wheels back on, removing the jack stands, and lowering the car back down.

THAT’S IT! super easy and shouldn’t even take the most novice of a person more than 2 hours.

No matter how exact you make the new arm length in comparison to the OEM arm. You are going to need to get an alignment.

I also do my own alignment because I have trust issues. I’m afraid of many things when taking my car to an alignment shop.

  • Are they going to scrape my lip on the ramps of the rack (if they don’t have an in-ground rack)
  • Are they going to scratch my paint with any part of their clothing, zippers, buttons, or snaps as they hang over my fenders to adjust the strut mounts.
  • Are they going to crack my fiberglass hood by using too much force, or pressing on the wrong part of the hood with their hands to get it latched.
  • Are they going to scratch my wheels with the laser beam reflectors they fasten to each wheel.
  • Are they going to properly adjust all my adjustable suspension arms? for example, loosen all the jam/lock nuts before turning the wrench to adjust.
  • Are they going to make sure they retighten all aforementioned jam/lock nuts? god forbid they forget and then I go crashing off course because a suspension arm has come unthreaded.
  • Are they going to be able to align it to “my specs” and not only what the computer says is spec?

It’s no doubt a very rudimentary way of doing it, but the numbers don’t lie. To ensure the wheels don’t bind and can easily move when adjusting toe. I have two layers of laminate flooring, with the shiny sides facing each other and two pieces of waxed paper sandwiched in-between the two layers of laminate.

Remember, my blog posts are merely a means to share information. I write them to help educate everyone. I want you all to be able to make an informed decision on whether you need “X” part or not. Hopefully, you came here to learn about rear adjustable toe arms and what benefits they can provide. To be completely transparent. Adjustable toe arms really aren’t a necessity and as I mentioned above, you can still be quick without them.

However, if you are at all serious about tracking your car, extracting every last bit of performance, and improving your lap times. The increased rigidity, lessened slop and improved suspension geometry you get from upgrading to aftermarket rear toe arms help keep the car more settled and more predictable. Along with having a much wider spectrum of adjustability, allowing you to dial in your alignment more precisely. Keep in mind it only takes a few 1/16ths of total toe in/out to drastically change how your car behaves on track.

I’m extremely satisfied with the Wunderladen Racing rear toe arms. As mentioned above, multiple companies make a decent rear toe arm. But the Wunderladen Racing one has some unique features; like a fully hexagonal arm that allows for an infinite amount of wrench placement when adjusting the toe. While this may seem like a small thing, it’s not! When you are actually under the car and adjusting the arm, there isn’t as much room as you think… especially if you are doing your alignment in your garage. Another great feature is the self-lubricating PTFE lined spherical that ensures years of trouble-free use. I have had them on my car now for over 2000 miles including track driving and they are still completely silent. No clicking or clunking! Lastly, we must support small companies like this. If we continue to support larger companies that outsource materials and production from China or similar countries. Small companies will go out of business and we are going to be forced to purchase sub-par quality items that haven’t even been thoroughly tested in real-world track conditions.

I bet you’d be surprised to find out just how many companies are outsourcing materials and production. Just think about it like Apple products and how on all their boxes it states, “Designed by Apple in California Assembled in China.” This is the same for most “popular” aftermarket companies that make parts for our cars. Just because the company is based in America, doesn’t mean that it was made here. It’s a very common practice to design the product here then send the CAD files overseas for production.

As always, I hope you enjoyed my long winded, overcomplicated explanations of basic parts and were able to at least learn a few things to help you with your own projects. I appreciate every single one of you for taking the time to digest it and for your continued support. Together we can help stop the spread of misinformation and blanket statements that only further confuse the masses. If you have any questions, comments, concerns, hate, anger, or just simply want to say hi. Please, don’t be afraid to reach out to me via Instagram @Functiontheory, Email Billy@Functiontheory.com, or simply comment on the post below and I will get back to you. I love hearing from everyone because it helps to keep the dream alive.


  1. Very nice write up, Billy. Just wanted to drop a comment to say I really appreciate the effort you put in your blog. Seeing these pictures reminded me I still have SPC camber arms to install…

    1. Keller, Thank you so much for reaching out! I love hearing from readers and I love even more that you can recognize the amount of effort that goes into them.
      OH YEA….I remember my first SPC camber arm install…. For some reason the post I did on installing those wasn’t to descriptive. Honestly, it most is because it was a bit challenging installing them.. Well maybe not challenging, but just aggravating. my only words of advice for installing them are. Make sure you have ratcheting wrenches as the clearance to get the bolt out is very tight. here’s a link to my post if you want to peruse through it for any helpful ideas https://functiontheory.com/2021/07/lowering-the-fk8/

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