Steeda S550 Mustang Rear IRS Subframe Support Braces (2015-2019 Coupe)

Steeda S550 Mustang Rear IRS Subframe Support Braces (2015-2019 Coupe)
555 5754


Product Install Instructions

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.

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

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!

MPN: 555-5754

Fitment & Features

Manufacturer: Steeda Autosports
Made in USA: Yes

Installation Information
Tools Required: Shop Tools
Time of Install: About 1 Hour
Level of Difficulty: Easy

Video Transcript

Customer Reviews

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:  from Tifton, GA. on 5/25/2017
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.
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Reviewed by:  from Loganville, Ga.. on 7/10/2017
Wheel hop is just about completely gone
I had the bushing kit put on. I'd say the wheel hop was reduced by about 50-75%. I then had the rear subframe support braces put on, and the wheel hop is just about completely gone. Awesome stuff.
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Reviewed by:  from California. on 5/30/2015
The car is showing zero wheel hop
Been on vacation the last week but I had a chance to hit the track last night. Wasn't planning on making any passes but it was dead and the cars that were making passes were hookin' really well so I decided to make a few. Unfortunately I didn't have the laptop with me to log the passes. First pass I left soft. 2000 RPM and no 2-step. Car hooked and zero wheel spin or hop. Hooked well enough that it bogged a bit off the line. Second pass. 3000 RPM on the 2-step, no launch control just RPM mode. Car dead hooked. No spin, no hop. Again, hooked well enough to bog the car a bit. Third pass. 3200 on the 2-step, RPM mode. Again, hooked with no hop and just a bit of spin.....enough to just chirp the tires. So, that's 6 passes with the Steeda bushing supports, sub frame braces and vertical links and the car is showing ZERO wheel hop. These last 3 were what I was really looking for as the car was hooking and showing no sign of hop at all.
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Reviewed by:  from Georgia. on 7/3/2015
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Reviewed by: (Verified Buyer)  from ORANGEBURG SC. on 8/3/2017
I would recommend these to anyone
First off I would like to say the shipping time and the quality of packaging is top notch. Second, I would like to point out that the customer service of Steeda as a whole is superb. The last point I want to make is these braces actually work. Under normal daily driving the braces keep the vehicle more firmly planted during acceleration. They keep the turning consistent and not strained. Under heavy load and launching I’ve notices 50% less wheel hop with TC off. With TC on there is even less wheel hop. Launching on the mustang with these braces seems more controlled with less wheel hop and faster acceleration. I would recommend these to anyone. The price is unbeatable for what is accomplished.
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Reviewed by:  from Florida. on 9/10/2015
wheel hop on my car is 100% eliminated
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 fiancé 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.
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Reviewed by:  from Georgia. on 5/7/2015
Thanks Steeda
Steeda IRS braces installed. Very easy install, took about 30 mins (mostly because I had to put the car down and move adjust the lift since it was still kind of in the way). Combined with the diff bushing inserts and the subframe inserts, the car is a completely different vehicle. Super happy!
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Reviewed by:  from Florida. on 10/14/2015
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.
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Reviewed by:  from California. on 11/13/2015
No noticeable NVH
Obviously no noticeable NVH changes, but the car does feel better when you gas it hard out of a corner. I'm looking forward to testing this beefed rear at the track soon.
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Reviewed by:  from Oklahoma. on 11/28/2015
Best suspension mod
The rear subframe braces are the best suspension modification next to the lowering springs. The rear is much more planted! Now I need the g trac k brace to tighten up the front end.
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Reviewed by:  from California. on 12/3/2015
Great job Steeda!
The rear sub frame braces are a great start to improving the IRS suspension. The rear end feels much tighter and there is no increase in NVH as stated by Steeda. Wheel hop has diminished when compared to stock and made a big difference. I feel that the braces joined with the Steeda G-Trac K brace up front will give the whole car a different feeling compared to the stock Performance Pack. Going around corners the car is well planted and makes a big difference in handling. I definitely recommend as an upgrade to the S550 Mustangs. Great job Steeda!
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Reviewed by:  from New Mexico. on 2/4/2016
Instant notice in handling performance
After I installed the Steeda IRS Subframe Support Braces again an instant notice in handling performance was felt. Kind of hard to explain but the cornering is just tighter; the back end wants to follow you around. Body roll is less present when I slalomed around some light posts in one of my neighborhood large open parking lots. All around for the price this is one of those additions you just have to put on your S550.
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Reviewed by:  from Florida. on 7/20/2015
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:  from Florida. on 3/27/2016
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".
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Reviewed by:  from Georgia. on 8/13/2015
What a major difference
Added the rear Steeda sway bar and iRS support brace. Also ordered the Steeda rear billet mounts for the sway bar. What a major difference these two made to the ride and stiffness. Feels like a new car (for the better). Feels a lot more solid.
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Reviewed by:  from Georgia. on 6/13/2015
Cornering has improved!
The added connecting points really help put control back into the car. Looks great under the car, tightens the handling and no increase in road noise whatsoever. Couldn't be happier!
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Reviewed by:  from Florida. on 4/6/2015
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:  from Louisville. on 10/21/2017
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:  from Gloucester Courthouse. on 11/25/2017
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:  from Brooksville, FL. on 11/26/2017
I am really amazed
David, had a chance to get the Mustang out today, after the Steeda mods that went on the car yesterday..... The mods are..... ( 1 ) Steeda Extreme G-Track K Member Brace... ( 2 ) Steeda Rear Vertical Links Aluminum.... ( 3 ) and Steeda Rear Subframe Support Brace IRS..... I know the the next mod is not a Steeda Product, but was Installed at the same time as the Steeda Mods, it is a Ford Racing Resonator Delete X-Pipe... And this is just the right sound I was looking ( for me anyhow ) for out of this new 2015 Mustang After driving the Mustang with your new Products, the whole Car ride is so much better in the rear, ( I'm thinking it the rear Vertical Links, rear of car It is stiffer, and the rear subframe braces also ) and the front end is really stiffed up also with the G-Track K-Member Brace..... David I am really amazed how much difference in the your products I put on, made in The suspension on my new 2015 5.0 Mustang..... You guys Rock at Steeda.. Thanks for Great Stuff....... John
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Reviewed by:  from California. on 5/18/2015
One of the biggest improvements to the handling of the car
One of the biggest improvements to the handling of the car is definitely the Steeda goodies all thanks to David here on the forum. He helped me so much picking out everything I should upgrade for all of the suspension parts to make this a great daily driver but also be able to take turns comfortably at high speeds and put the power to the ground. One of the first Steeda upgrades Slammered threw on for me was the Front/Rear Sway Bars and the IRS Support Brace and damn did it make a pretty damn noticeable difference in turning. No I don't track this car as of right now but the closest I get to taking turns and curves is off ramps from the highways and I've done decent speeds coming through those turns. The sway bars help keep the car planted and definitely boost the handling capability that the IRS already provides. I also installed the billet mounts and they look damn good with the blue sway bars and definitely are top notch quality over the stock mounts from Ford. Wheel hop has been one of the most notorious things the S550 platform has encountered with the new IRS system. Wheel hop is a "No no" and Steeda's IRS bushings are definitely the first step to knock out way more than 50% of the notorious wheel hop. When taking the bushing out of the box and taking a peek at my new goodies, I was amazed of the quality that is put into the manufacturing of the parts Steeda offers. IRS Bushing from Steeda is a must if you're looking to eliminate more the 50% of the wheel hop. It's great quality and definitely helps put the power to ground. When hitting it and shifting from 2nd to 3rd it's a whole new feel and it just takes off.
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Reviewed by:  from Florida. on 3/5/2016
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:  from Mississippi. on 3/30/2016
Great item!!!!
Easy install, great item!!!!!
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Reviewed by:  from Louisiana. on 4/4/2016
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:  from Arkansas. on 5/1/2016
There are no reviews for this product!

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