Steeda S550 Mustang Coupe Rear IRS Subframe Support Braces (2015-2020)

Steeda S550 Mustang  Coupe Rear IRS Subframe Support Braces (2015-2020)
$55.00 (18%)

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Suggested Mods


With the release of the new 2015-2019 S550 Mustang, Steeda knew that addressing the IRS system would be a top priority. Being the first production Mustang with an IRS since the 03/04 Cobra's, we knew there would be a great opportunity to capitalize on Ford's new piece by giving it the Steeda advantage. As with any suspension system, deflection is an issue if it's present. Anytime a piece is moving, twisting or vibrating when it should be stationary is a major problem. One of the areas team Steeda wanted to focus on was the rear IRS subframe.

As you have seen with our IRS Subframe Bushing Support System, it limits the movement of the subframe by filling in the voids of the OE bushings. With Steeda's IRS Subframe Support Braces, we have taken the S550 rear suspension to another level!

Our Steeda S550 Mustang Rear IRS Subframe Braces for 2015-2019 Fastback coupe Mustang 5.0L GT, 5.2L GT350, 2.3L EcoBoost, and 3.7L V6 fastback coupe (non-convertible) is built in-house from 4130 chrome moly steel and powdercoated silver metal flake, this part isn't only strong - it also looks great under your new Mustang! What we did was tie together 3 very important points on the S550 chassis. We utilized existing threaded holes in the rocker panel (the strongest part of the body) and connected that to the front mounting location of the IRS subframe and the rear mount of the lower control arm and toe link. Connecting these 3 points together not only adds rigidity that was lacking in the rear, but also more control of the whole car.

Also, unlike competitors kits that have not been released yet and only replace the factory bracket, our Steeda kit supports that bracket while connecting to 2 additional locations, therefore providing twice the support! Best part about this kit is it uses all existing holes in the chassis so the car doesn''t have to be modified in any way and adds no NVH whatsoever.

PATENT NO.: US D784,211 S

Purchase your Steeda S550 Mustang Rear IRS Subframe Braces for your Fastback coupe S550 2015,2016,2017,2018,2019 Mustang GT, GT350, EcoBoost, and V6 (non-convertible) at Steeda Autosports today!

Product Benefits
  • Better handling for more stable cornering
  • Limits IRS sub frame movement
  • No permanent modifications necessary
  • No added NVH
  • 50% more connecting points
  • Reduces wheel hop
  • Lifetime warranty
  • Installation does not require removal of cradle

CA Residents: Cancer and Reproductive Harm WARNING

Hi everybody Brian from Here today to speak to you about our Subframe Braces for the S550 Mustang. When Ford was developing the S550 Mustang they built it so that it could be competitive around the world and popular around the world. And this posed a challenge for them. The challenge was switching over to and independent rear suspension. They hadn't offered a Mustang with independent rear suspension since 2003-2004. So changing that over was quite the challenge for them. When they did this, they utilized a subframe that bolted to the chassis and that was held together by four bolts. Now at those four bolts are bushings and the reason I'm telling you this well they left some room for improvement! To build on that statement further the bushings are fairly soft from the factory, and the reason that Ford designed these bushing to be relatively soft was to absorb any sort of vibration that might be transmitted through the subframe and isolate that from the body. Now that's great for driving the car everyday but as soon as you throttle into it you get wheel hop! We have many solutions for you but today we're going to focus on the subframe braces. Now the way these work is they connect in three strategic places on the back of the car. They mount toward the front of the rear tire to the chassis, come back to the front mounting point of the subframe and then back out toward the lower control arm and tow arm to reinforce those points. Now it's just not a matter of reinforcing those points it's also a matter of triangulating those three points. This is going to eliminate any sort of deflection left or right as well as forward backward and you know that triangulating something is going to add rigidity. Now this is important for a couple of reasons. That rigidity will make the car communicate better with you the driver. In addition, it's going to help keep the subframe planted in place and help remove that defection in those soft bushings. whether it be side to side or forward backward. It's going to help reduce wheel hop coming out of corners as well as wheel hop you experience when you accelerate hard going straight. And to further legitimize the efforts we put into designing these, we utilize these on our #20 SARRC Championship S550 Mustang as well as our World Record setting Silver Bullet Mustang. And since we know that weight is the enemy of performance, we've constructed the Subframe Braces out of 4130 chromoly, which is light weight and extremely strong. In addition we've powder coated them for durability and if anybody seeks a peek underneath the car it's going to look great! Now these are also really easy to install. No modifications are needed to the car and we provide all the necessary hardware to mount them. These also carry our lifetime warranty. In addition they're Made in the U.S.A. at our Valdosta Georgia facility. Because Speed Matters! Subscribe to our Youtube Channel If you enjoyed this video, be sure to hit Like. Don't forget to follow us on Social Media. Have a great day!

Fitment & Features


Manufacturer: Steeda Autosports
Made in USA: Yes

Installation Information:

Level of Difficulty: Easy
Install Time: About 45 Minutes
Tools Required: Basic Shop Tools
Print Instructions:
Install Video:

Vehicle Fitment:

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

Customer Reviews

Massively improved handling
I have only had these on for two days but I instantly saw massive improvements in turning and heavy acceleration. I have made a number of sharp turns in 1st gear and they have been super smooth with no sign of giving out like it would before. I have also gotten a few clear freeway onramps to really let her go and there was zero sway unlike before, the car stayed straight as an arrow. This one piece has greatly increased my confidence in the car and I no longer feel on the verge of losing control at times. I would highly recommend this as a first or even only suspension upgrade. The results were impressive, the install was easy, and the price is cheap compared to coilovers or other expensive suspension mods. If you don't feel confident in your car at times, get these now!
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Reviewed by: (Verified Buyer) Dan A from . on 9/10/2019
2019 bullitt
Very good product
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Reviewed by: (Verified Buyer) Marc Mcgraw from Canada. on 8/1/2019
2019 Bullitt
A must have no mustang completed without steeda sub frame connectors..
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Reviewed by: (Verified Buyer) Benjamin Hernandez from Texas. on 7/29/2019
great product
I am a old SCCA road racer and love modifying my street cars to handle the best the can if and when I ever it to the track for a HPDE day. I have several Steeda handling products on my 2018 GT PP1 and love them all. I am not a tire burner and didnt really know if this would help the unbalance feel I seam to notice in the rear of the car, but thought I would give it a try. Adding this subframe support brace really brought everything together. I highly recommend this for the curves that you want to master.
Did you find this helpful?  5 of 5 Found Helpful
Reviewed by: (Verified Buyer) willis williams from CA. on 5/2/2019
Stop the hop
These are top notch products and highly recommend them! Very easy install .??
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Reviewed by: (Verified Buyer) Matt Wulf from TN. on 4/4/2019
Best thing to stop wheel hop
I bought mine before they had the “stop the hop kit” but the best thing I bought to get rid of wheel hop, and keep the tires planted down on the road or track. The “stop the hop” kit from steeda should be the second thing you buy for the mustang!!! (First being the jacking rails to make install of the kit easier)
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Reviewed by: Jack walker from Acworth. on 6/12/2018
Fantastic Product
I installed the braces in about 1hr using the list of tools provided in the instructions and it went smoothly with only 1 very minor issue! When doing this job I suggest that you tap the unused factory threaded holes prior to starting the installation they had some corrosion that didn’t allow the bolts to start properly. I took it out for a dirive after the installation and listened for any noises and drove easy . There were none . I then drove somewhat aggressively and the wheel hop was no longer there and the car felt much better as far as stiffness goes! This is a fantastic product and I highly recommend it to everyone!
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Reviewed by: Michael from Brooksville, FL. on 11/26/2017
Like these Support Braces
Installed these support braces a couple days ago using the easy to follow written instructions after viewing an installation video on u-tube. The install (driveway on jack stands) was easy and straight forward taking about two hours from start to finish. During post install test drive, the car felt much more planted on hard acceleration and definitely tracked straighter without getting sideways when shifting into second and third. No change to normal ride characteristics (harshness etc.) or change to NVH. Really like the planted feeling of the cars rear end when punching it. Recommend this item to help keep car straight when accelerating hard and banging a gear. No cons.
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Reviewed by: Joseph Gallagher from Gloucester Courthouse. on 11/25/2017
Quality Braces
Excellent pieces, worth the money. I was lucky enough to get a never-installed pair from a forum member for half the normal cost. I didn't buy them so much for wheel hop as rear end rigidity. I have a nonPP premium GT and have always noticed that there is quite a bit of movement in the rear end during tight cornering. It's not hugely noticeable but it bothered me. These braces completely fix that issue. They would've gone on in about 15 minutes with ramps but the middle bolt location on the car-side needed to be re-tapped from rust and road grime. If you have taps handy, just go ahead and ream out the hole with a 10-1.5mm before you start the install. I got the braces on and then had to remove them to get to the threads. Otherwise, no fitment issues as others have noticed. The rear end is a little stiffer ride than before now, but it's from parts not moving that aren't supposed to move, so I'll live. Exceptionally happy with the purchase!
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Reviewed by: Joel Boyer from Louisville. on 10/21/2017
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Reviewed by: (Verified Buyer) Richard Krabbe from ORANGEBURG SC. on 8/3/2017
So much better
Put these braces on, and saw an immediate difference in the feel during a launch. Helps take the wheel hop out an tightens up the rear of the car. Thanks to Randy for all your advice.
Did you find this helpful?  9 of 9 Found Helpful
Reviewed by: Paul C. from Loganville, Ga.. on 7/10/2017
Review of subframe braces and vertical lengths
Recently had these parts installed at the Steeda facility in Valdosta, GA. and all I can say is WOW what a difference. First, let me start by saying my car is boosted and gets no traction on street tires and is an automatic. After, I picked the car up with my 7 year old son, of course we had to try it out. After, accelerating really hard at 25mph, my son looked at me and said, Daddy, it doesn't get sideways anymore. I looked at him and I said your rite. So, if your looking at any of these parts, I highly recommend them. You want be disappointed. Now, waiting to see what else Steeda may be releasing for the drag setup. Gonna have Steeda install the alignment kit and rear differential upgrade, next. Can't wait, one happy customer here. Thx. STEEDA.
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Reviewed by: MICHAEL HANCOCK from Tifton, GA. on 5/25/2017
What a difference theses Steeda sub frame connectors made
Honestly, I did not think this suspension mod would do much for my slightly modded 2015 GT. The car has a CAI, GT350IM, long-tubes on back with 3.55 gearing from the factory. So not exactly a high horsepower car but enough to cause excessive wheel hop on throttle blips. What a difference theses Steeda sub frame connectors made, I was not expecting this. The car accelerate, within reason, without the back end jumping loose every time. Some better tires and it would really tie it all together in a very simple package. The coonectors are well made, high quality
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Reviewed by: JM from . on 4/2/2017
you can add this subframe brace for not only extra wheel hop prevention, but also improved handing
There's always this debate as to whether S550 owners should get the competitors lockout kit or this for wheel hop. The most directly comparable solution from Steeda to the competition's lockout kit, IMO, is the IRS alignment inserts + IRS bushing supports. Then you can add this subframe brace for not only extra wheel hop prevention, but also improved handing and driver confidence on the street or road course. This brace also works in tandem with the aforementioned parts to keep the IRS straight and solid during launches at the drag strip and it does so from hard points on the IRS and using Ford factory subframe bracing locations, not with a bracket that slips into the IRS cradle bushing and with a steep angle connects to the vehicle frame with small 35 torque bolts going through slotted holes in the same direction as the movement its supposed to prevent. Look, they are two different approaches with a similar goal. I chose Steeda's solution because I road course my car and even a novice that's spoken to just a few seasoned road course vets knows that triangles make a subframe better.
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Reviewed by: wildcatgoal from . on 3/25/2017
no more wheel hop
I installed mine with the weight of the car on the tires (I have a 4 post lift). Everything lined up perfectly on the driver's side, the center hole was off just enough on the passenger side that I was concerned I would cross thread the fastener if I forced it but I was able to easily lever it into alignment with a screw driver.
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Reviewed by: Nick S. from Florida. on 12/10/2016
car should drive like this out of the factory!
I spend Sunday installing Steeda's front and rear sway bars (with billet aluminum sway bar bushings) on my 2015 GT PP. This is in addition to the progressive springs and sub frame bushing supports that are already installed. The installation of the rear parts were easy while the front was more tedious but not impossible for the average mechanically inclined person. I opted for maximum stiffness on the sway bars for the best handling performance. visibly there is a huge difference in the side and quality of the sway bars. Steeda's are much more stout and the bushing are significantly stiffer, the mounts are lighter (based on the standard mounts that come with the sway bars) but a much better design. The sub frame braces look like the perfect way to tie the IRS sub frame into the vehicle and "tighten things up". The brace connects near the jack points on each side to two points on the sub frame and one point in between creating a triangle for some serious stability. This is a tight fit so make sure you follow the instructions from Steeda and keep the bolts loose until things are set. I haven't had the car on the track yet, but there is a huge difference in just daily driving. I've hit a couple of curves hard and the car seems to dive into them and there is much more confidence in the car. I hit a pretty sharp curve the last 2 days on my way to work and I don't feel any understeer at all (at least I can't tell) I was doing between 60-70 mph through the turn it just felt nice! All in all I made a great choice. Steeda should have sold these to ford during manufacturing and the car should drive like this out of the factory!
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Reviewed by: Mike W. from Texas. on 11/9/2016
Completely different experience
I put the car to a slight test this morning on my way to work. I usually take this one turn at about 60mph and I can feel the car pulling, today I hit it at 70mph and the car felt like it dove into the turn. completely different experience in a very positive way.
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Reviewed by: Anthony K. from Pennsylvania. on 10/14/2016
Totally happy
Installed this on my 2015 GT non PP in combination with Ford Racing Strut Tower Brace and G-Track Extreme. Car is exactly what I wanted. The car goes where I point it, and is very composed on rough roads. Went with 4 stars because one of the mounting locations just didn't line up. I had to again get the pry bar out to get the threads to start on the bolt. Not that big of a deal, but the install videos are not the norm. Used floor jack and jack stands and the install was just over 60 minutes. Totally happy.
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Reviewed by: Scott B. from Alabama. on 9/22/2016
the tires stay planted
I installed these braces on my EcoBoost recently and the difference was immediate! The rear is way more stable than before. I can push through sweeping corners and the tires stay planted. Now I gotta install my other Steeda parts and go back to the track to redeem myself.
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Reviewed by: Rick A. from Georgia. on 7/18/2016
Bye, bye wheel hop!
Today I added the Steeda Rear IRS Subframe Support Braces and Bushing Support system. It really made a difference stiffening up the suspension. I will install the Steeda Vertical Links next week. Bye, bye wheel hop!
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Reviewed by: Matthew Z. from Louisiana. on 6/10/2016
Tracks like a go kart now
On my previously stock GT non-PP i had a odd sensation while cornering that could best be described as a "rubber-band" feeling. I believe it was compliance of the subframe bushings. It was unnerving. Felt like the start of the tires breaking loose - but it wasn't. I installed the Steeda rear IRS bushing support kit and the IRS braces and the sensation went away. Much improved cornering afterward. I was inspired by the improvement so I added the Steeda springs and swaybars. Tracks like a go kart now.
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Reviewed by: Larry H. from Arkansas. on 5/1/2016
Car feels completely different now
Installed my Steeda G Trac Brace and Steeda IRS subframe brace. Car feels completely different now. Way more composed and even rides more smoothly over all the poorly paved roads and potholes in south east PA. The front end feels like it rides on rails now with the g trac and FRPP strut tower kit.
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Reviewed by: Kalvin M. from Pennsylvania. on 4/27/2016
Great item!!!!
Easy install, great item!!!!!
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Reviewed by: Ted B. from Louisiana. on 4/4/2016
Well worth it
The G-Trac brace and IRS braces areally both well worth it. G-Trac really helped tie my front end together and made a very noticeable difference going into the corners. Nice steering response gains. The IRS braces help tie the rear end to the rest of the car. Doesn't feel like the rear is walking out on you when you're getting into it and it seems to help with some of the deflection I was feeling, and made it tighter going into corners. You won't be disappointed with them!
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Reviewed by: JD M. from Mississippi. on 3/30/2016
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.
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Reviewed by: Frank L. from Florida. on 3/27/2016
There are no reviews for this product!

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