Steeda Rear Subframe Support Braces IRS Fastback Mustang 2015-2024

97% of 100


  • Limits Irs Sub-Frame Movement
  • No Permanent Modifications
  • 50% More Connection Points
  • Improves Handling
MSRP $319.95
You save $8.96

Steeda Rear IRS Subframe Support Braces for 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023 and 2024 Fastback Mustangs.

As you may have seen, Steeda's IRS Subframe Bushing Support System solved many problems with a quick and easy solution that limits the movement of the subframe by filling in the voids of the OE bushings. Now with Steeda’s IRS Subframe Support Braces, they have taken the S550 rear suspension to another level!

Features and Benefits:
- Better Handling for More Stable Cornering
- Limits IRS Sub-Frame Movement
- No Permanent Modifications Necessary
- No Added NVH (Noise, Vibration and Harshness)
- 50% More Connecting Points
- Reduces Wheel Hop
- Made In The USA

The Steeda S550 Mustang Rear IRS Subframe Braces for 2015-2024 Fastback Mustang are built in-house from 4130 chrome moly steel and powdercoated silver metal flake, this part isn’t only strong, it will look great under your new Mustang! What they did was tie together 3 very important points on the S550 chassis. Steeda utilized existing threaded holes in the rocker panel 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.

*Will NOT work with Convertible Mustang Models.

California Residents: Proposition 65 Warning

Installation Difficulty


Novice skill is required for this installation.

Installation Videos

Video Transcript

Today we're going to take another step towards limiting the wheel hop on my 2018 Mustang, by installing a set of IRS braces from Steeda. These Steeda IRS subframe braces are going to fit all 2015-2022 Mustangs Fastbacks. And the way they're going to work, is they're basically going to bolt the frame to the subframe itself to add additional support structure, and stop the subframe from moving. Movement in the subframe is one of the major causes of wheel hop.

These are going to be a direct bolt on installation, include all necessary hardware and are made right here in the USA. For this installation, need a lift, or a jack and jack stands, 3/8 ratchet, 15 mm socket, and a 10 mm Alan key. If you do have to move your subframe, you'll also need a 13 mm and 21 mm socket.

Now, the Steeda brace is going to mount in three points. You're going to mount here, back here where the subframe bolts in, and then back here on the subframe itself. Now, the first step in the process is remove this rear bolt. Before we can install the brace, you have to grab this threaded insert. What you're going to do, is put this right up in here, you're just going to line it up. The bolt we install, will pull down on that, and hold to the back part of the brace.

Now, we're going to put the IRS brace up into place, where it's going to go, and loosely start the front bolts. Now, I'll grab the shorter bolt with the Alan head, and thread that into the plate we installed earlier. Another longer bolt, will go back here. What you have to do, is take this nut, basically put it on top of the subframe, and then get it lined up, so we can tighten it down.

Now the last step, is going to be the middle bolt here. Now on a good day, this will go up and line up with the thread on this plate. On our case, this plate's been off a couple times for other rear suspension upgrades, and it does not line up. If that's the case with your car, loosen these two 13s, and this 21, and just shim it until it lines up.

At this point, use a jack or a pole jack if you're on a lift, lift it up enough to take the weight off of it, so you can move it. Okay, now that all the bolts are started, we can go through and tighten everything down. Now I do want to mention, once you have this bolt aligned and in place, you might not be able to get to the blue bolt to torque it. If that's the case, tighten these down here to hold it in place, so it doesn't move, pull the subframe brace off really quickly and then torque that bolt. This won't move, and the bolt will still be lined up.

You're going to torque everything down to the Steeda supplied specs. Torque the factory subframe bolts down. Repeat the process on the other side, and your installation's finished. The Steeda IRS subframe braces did an excellent job on my 2015 Mustang. And I know they're going to work great on my 2022 as well. Now again, these are Fastback only. They will not fit your Mustang convertible. But as you saw, they're pretty straight forward installation, should take you no more than about an hour and a half, or so, and be back on the road in no time.

Vehicle Fitment

This product will fit the following Mustang years:

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