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Steeda S550 Mustang IRS Subframe Alignment Kit (2015-2022)

20 Review(s)
$37.49 (42%)
Steeda S550 Mustang IRS Subframe Alignment Kit is made from CNC-machined Delrin, adds no NVH, and aligns subframe to chassis
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Part Number: 555 4438
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Suggested Mods


You asked and Steeda listened! We were lucky that our 5 in-house 2015+ S550 Mustangs all came with the rear subframe aligned properly from the factory. But, what we noticed was a lot of people out there were not as lucky. The team here at Steeda went hard to work when we started fielding calls of the rear subframe being misaligned from the factory. So here you have it, Steeda's new S550 IRS subframe alignment kit!

The S550's subframe mounting holes are very large compared to the subframe mounting bolts. Since there is a large difference in bolt and hole size, the subframe can be mis-aligned from the factory up to 1/2" left to right.

The Steeda S550 Mustang IRS Subframe Alignment Kit is made from CNC-machined Delrin to avoid putting two dissimilar metals next to each other, preventing corrosion. Delrin is also less weight then aluminum or steel inserts and therefore keeping performance in mind. The Delrin sleeves slide into the subframe mounting holes, and fill the extra space left between the subframe mount and bolt from the factory.

Our Steeda S550 Mustang IRS Subframe Alignment Kit guarantees that the subframe will be bolted to the same location every time it is lowered. Eliminating the need for unnecessary alignments.

Note: Customers running the CB005 Kit will need to purchase this part Steeda Mustang Alignment Kit for the S550 Rear Subframe for BMR CB005 Kit (15-17 All). An alignment is needed upon initial installation, due to the fact it could have been mis-aligned from the factory and with it now being squared in the chassis, some adjustments might need to be made.

Purchase your Steeda S550 Mustang IRS Subframe Alignment Kit for your 2015+ Mustang GT, GT350, EcoBoost, and V6 at Steeda Autosports today!

Also fits the S550 GT500

Product Benefits
  • Aligns subframe to chassis
  • No increase in NVH
  • Easy to install
  • No permanent modifications
  • Limited lifetime warranty
  • No additional hardware needed

CA Residents: Cancer and Reproductive Harm WARNING

Hi everybody Brian from Here today to show you our Subframe Alignment Bushings for the S550 Mustang. Don't be fooled by the size of these. These are a small part that makes a huge improvement and there is two key improvements that they make. One is that they align the subframe to the car. Now from the factory there's quite a bit of variance. We've seen about a half inch to the left or about a half inch to the right of where the subframe falls during assembly. What this does is it effects the steer ahead of the car. So these force the subframe to be aligned perfectly within the four main mounting positions under the car. This is going to square it up, give you more proper alignment and better feedback. Another benefit is because these align the subframe perfectly to the car if you need to lower the subframe in the future to say replace rear springs or change suspension setups it won't force you to realign the car. Now you should always check your alignment anyway, especially if your making suspension changes but these will ensure that goes exactly where back where it was. In addition to aligning the subframe, these also help to lock it in place. Now we've talked a lot about wheel hop and one of the things that lead to wheel hop is when that subframe wants to walk around. Now we've got our subframe bushing support collar system which works perfectly along with alignment kit. Both of them together, lock the subframe into place. Just like that support system, the alignment bushings don't ad any noise, vibration or harshness. Furthermore, installation of these doesn't require any modifications to your vehicle. They're also backed by our lifetime warranty. We proudly manufacture these in the USA at our Valdosta, Georgia facility. If you have any questions or comments on these, please feel free to post below. If you enjoyed the content of this video, click like and be sure to share it with your buddies. Also, subscribe to our Youtube Channel to see more. If you'd like to learn more about these or as well as our other great products visit and don't forget to follow us on social media. Most importantly thank you and have a great day!
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Fitment & Features


Manufacturer: Steeda Autosports
Made in USA: Yes

Installation Information:

Level of Difficulty: Tech Recommended
Install Time: About 1 Hour
Tools Required: Basic Shop Tools
Print Instructions: Installation Instructions
Install Video:

Vehicle Fitment:

Fits Model Year: 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022

Customer Reviews

Rating Snapshot

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Average Customer Ratings


Alignment bushings fit like a glove, only thing is I had installed IRS supports a good while back so had to drop them down to install bushings. Worked great thanks to steeda!
Did you find this helpful? 
Must Have
Excellent for aligning the rear subframe. Mine was off from the factory and after installation the car seems to track much straighter on the highway. Thank you!
Did you find this helpful?  1 of 1 Found Helpful
Alignment kit
The whiteline subframe bushings added a significant feel in ride and launch quality, I coupled this with the subframe alignment kit from Steeda all in all I definitely recommend ??
Did you find this helpful?  1 of 1 Found Helpful
Alignment Kit
Took 10 minutes to have peace of mind. Installed in a breeze. Great product!
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Absolute must!
This product works.....period. Keeps you straight, keeps you in control. Absolutely no alignment issues. This should be you first modification if you play hard.
Did you find this helpful? 
Does the job
Item works as intended, do recommend doing this mod first seeing as how after the IRS has been undone a few times it can get tricky to have it aligned just right for install. Pry bars recommended if your have already fully removed these 4 bolts.
Did you find this helpful? 
Excellent product
I bought these along with the irs bushing supports, billet vertical links and differential bushing kit. The irs from factory was actually off by about a 1/4 inch to the right and thanks to these i got the irs squared. Really simple and easy to install, if being installed by themselves, with minimal tools and effort. I cant tell you how the car handles with this product alone since I installed it simultaneously with other steeda products. Would definitely recommend this product.
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Perfect fit. Good product.
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Simple yet effective!
After installing these and see how much movement the subframe has, I am convinced EVERY car needs these! I did the install at the same time as my Steeda Sport Progressives so install was a breeze! Very tight tolerances so be prepared to lightly tap a couple in. Thanks to Steeda, I know my subframe alignment will be straight and true no matter how many times I R&R it!
Did you find this helpful? 
IRS subframe alignment inserts
wasn't sure what to call them, dowls or pins i don't know. these were installed with some other items but i can not tell a difference because i had no issues before with how the car felt. these were just extra insurance to assure nothing moves around.
Did you find this helpful?  0 of 1 Found Helpful
Excellent Product!
These really helped keep my subframe from shifting too much when I also had the bushing support system, sport progressives and pro action shocks installed. My alignment was easier to do because of it, the guy told me so! Another example of Steeda thinking outside the box to make our lives better as consumers of speed!
Did you find this helpful?  8 of 8 Found Helpful
Verified Buyer  
What a difference in getting rid of the IRS spongy feel.
What a difference in getting rid of the IRS spongy feel. With a set of Koni sports it elevated the rear end to an exciting level of performance. 2015 GT.
Did you find this helpful?  5 of 5 Found Helpful
These mixed with the IRS bushing supports from Steeda and you have a lot of your wheel hop resolved
These do two things: (1) they force the IRS cradle on-center to each of the bolt holes in the vehicle's frame. This makes sure your rear wheels and wheel gaps/fitments are even on each side and improves your ability to get a quality performance alignment and install other Steeda (or even competitor) parts. (2) These shore up/reinforce the inner part of the IRS bushing. You will read misinformation on the forums that this is not the case, yet the competition sells a product that fits into the IRS bushings to do just that. These mixed with the IRS bushing supports from Steeda and you have a lot of your wheel hop resolved and a much more connected IRS.
Did you find this helpful?  6 of 6 Found Helpful
wheel hop on my car is 100% elimated
A couple of months ago, I started looking into overhauling the suspension of my 2015 GT PP. Up to that point, I had put about 7000 miles on my Mustang which allowed me to get a good sense of the issues with the IRS and overall suspension in stock form. Specifically, I wanted to stiffen up the entire rear end and eliminate the dreaded wheel hop while keeping NVH as close to the stock levels as possible. I also decided to replace the stock PP springs and sway bars in order to improve the overall handing, reduce body roll/brake dive and get rid of the bouncy ride. After going through a ton of feedback on the various solutions from the aftermarket (a lot of which came from fellow mustang6g members), I decided to go with Steeda. Below are the parts I chose to go with. Differential Bushings (Red/Street) Subframe Alignment Kit Subframe Bushing Support Vertical Links Rear Toe Link Subframe Suport Braces Linear Sport Springs Front and Rear Sway Bars and Billet Sway Bar Mounts Bumpsteer Kit I already had the Extreme G-Trak Brace installed. Now to the most important part...the results. The handling of the car is on a whole different level after the suspension upgrades. Minimal pitch and roll during braking, turns and transitions. Overall, the entire car is very tight with much better turn in. As expected, the biggest improvement is the rear end. The power delivery through the IRS is fantastic. The wheel hop on my car is 100% eliminated. The rear tires feel as if they are glued to the ground. Coming out of corners, I am able to get on the throttle earlier and more aggressively without any drama. In terms of NVH, I hear some gear whine in 6th gear under minimal throttle between 75 and 80mph (windows closed/stereo off) as a result of the differential bushing inserts. Apart from that, I can't tell a difference compared to stock. Even the ride quality feels great. My fiance couldn't tell that anything had been done to the car. Overall, I am very happy with the results. Props to Steeda for the excellent work they have done. In the near future, I am looking forward to adding a quality set of performance shocks/struts and hitting the road course.
Did you find this helpful?  5 of 5 Found Helpful
This is the way the car should be with the PP
Since I was going to have the car up on jack stands in my driveway, I figured I'd do just about everything at once. Installed the Steeda IRS subframe bushing supports, alignment inserts, differential bushing supports(black), transmission bushing insert, and the Steeda shifter base bushing bracket along with the FR touring cat back. I had to have the upgraded bushing in the knuckle done at the Ford dealer. The bounce is gone! This is the way the car should be with the PP.
Did you find this helpful?  3 of 3 Found Helpful
The handling of the car is just perfect
I am beyond please with everything that Jamie did for the installation and alignment. David was an absolute pleasure to deal with in buying and setting up the appointment for me. Everyone at Steeda has been a joy. The car has been completely transformed. The ride quality with the progressive springs is 3 times better vs. the stock GTPP springs. The handling of the car is just perfect. It is so, so flat now when pushing the car hard in any type of turn. Brake dive has been greatly reduced. I would say by 80-90%. I can mash the brake pedal and it just stops, so tried and true. The front-end barely dives at all. This is from 70-75mph and just mashing the pedal. It truly begs for more speed when entering turns. Of course, this only on roads and not a race track or autoX course. Wheel hop has been greatly reduced. I still have a couple more parts to order to virtually eliminate it all together and those will be ordered at a later date. Shifting hard to 2nd gear, I just now get wheel spin and no hop. Only time I get a little hop is via a hard launch. But again, it is greatly reduced and doesn't happen all the time. The car is so quiet, no increase in NVH in anyway. This has been some of the best money I have ever spent on any car mods, PERIOD. Their parts deliver what they promise and produce outstanding results. Anyone on the fence, I highly recommend you go ahead and purchase their stuff.
Did you find this helpful?  3 of 3 Found Helpful
I am a Steeda believer
The car is a totally different handling car. Took the wife for a ride today and she said it is smoother than before. Much less bouncy. That is good news to me. Cause if the wife is happy I am happy. But I will say that these mods have really changed my confidence in the car. I had one little 30mile spirited section with S curves on my way home that normally when they say 45mph.. you can take them at 55mph... I took them at 70mph and the car was just planted solid. No roll, no rebound and no breaking loose on the rear when I accelerated from the apex. It just transitioned smoothly and predictably. Now the only thing the wife did notice was the gear whine. Yes the Red differential bushing will cause some gear whine, but I have been told that replacing the stock gear oil in the rear end will help quiet that noise down. We will see as I will most likely change mine out here in the next week. Amsoil or Royal Purple is what a lot of people recommended. So, all in all, if someone is on the fence about these suspension upgrades, just do it. The guys at Steeda are top notch and know their stuff. Almost all of them have Mustangs and the owner even races them. A final shout out to [email protected] What a great help he was. He made sure everything was ready and there, his recommendations were spot on. David, again, Thank you man. I can hardly wait for the next batch of Steeda goodies come out.. Count me in already. I am a Steeda believer.
Did you find this helpful?  2 of 2 Found Helpful
The car feels so much more planted to the road
This is the first time I've ever done anything suspension wise to my car, David @ Steeda helped out greatly with all my questions as well as getting me setup with an install at their Pompano location with a tour of some badass shop cars and their facility. Everyone @ Steeda - David, Patrick, Matt were great and made sure I was happy with everything. I can't recommend their shop enough to anyone in the area and Matt did an awesome job with everything on the install, even tack welded my Gibson exhaust and turned their clamps a bit to help out. I won't have a chance to do pics this weekend of my spot on the beach as that will give a good before/after comparison when I put them together. The car feels so much more planted to the road, even just turning out of their parking lot I could tell everything felt more connected and precise to what I was telling the car to do. It basically now goes where I want it instead of reacting to what I'm asking it to do if that makes any sense at all? I had some open highway and did a little bit of careful back and forth in my lane and I felt completely planted and not bouncing around back and forth in my seat. Almost found myself doing slalom in between some construction barrels but given how my morning went I decided against it. The springs give the car the look I wanted and make the Vossen wheels look that much better. Nice tighter rebound than stock PP springs and reduces the overall bouncy ness on some of those highway stretches where it feels like you're hitting hydraulics for a half a mile. Also any bridges or overpasses with rough spots where you enter/leave them were solid. The MT-82 bushing insert is noticeable and I had much easier downshifts for highway passes on the way home, feels like a much more solid shift that I had to get a bit used to in a good way. I didn't do any hard launches or try to break the rear end loose at all since I was just getting used to it, will report back later on that. I can't really report on some of the individual IRS components since they all went in at the same time, but I am noticing a slight (and I mean slight) gear wine from the rear with the Black bushings. It's only really noticeable if you try to make it happen and barely push the gas at cruising speed. Nothing I'm worried about and after 4 hours of driving it home windows down and up for a few sprinkles it does not bother at me all. It's not all the time either or in any specific gear so no biggie as far as I'm concerned.
Did you find this helpful?  2 of 2 Found Helpful
Honestly, the fitment is so unbelievable
Added even more STEEDA!!! IRS Brackets and Centering spacers. Lucky for me, we set the IRS properly and the centering spacers went right in, easssyyy. The brackets also went right in. I had a slight snag with the front OE bolt, WD40 did the trick. All looks unreal. Spent the day washing both my cars, so no driving impressions, but I just love the idea that everything is so fastened. Honestly, the fitment is so unbelievable, that sometimes I think Steeda help develop the car. lol.
Did you find this helpful?  2 of 3 Found Helpful
What an amazing difference
Installed the Steeda IRS Subframe Alignment Bushings, and Steeda IRS Subframe Bushing Support this weekend. What an amazing difference, and not too difficult of an install. I definitely recommend anyone that is thinking about these to knock them out at the same time.
Did you find this helpful?  0 of 1 Found Helpful
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