Steeda Mustang Rear Chassis X-Brace (2005-2014)

18 Review(s)
$40.00 (11%)
Steedas S197 rear chassis X-brace does not require a rear seat delete.This brace installs in the chassis area between the rear wheel wells behind the rear seats which effectively couples this part of the rear structure together to increase chassis rigidi

Part Number: 555 5093
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Our latest rear chassis X-brace addresses the fact that not everyone wants to get rid of their rear seats for the added benefit of the rear chassis brace. Obtaining the rear seat delete parts from the Boss 302 can be an expensive task, and having a rear seat delete made can be a challenge as well.

After listening to these concerns from our customers, the result is our Steeda Rear Chassis X-brace that does not require a rear seat delete. This brace installs in the chassis area between the rear wheel wells behind the rear seats which effectively couples this part of the rear structure together to increase chassis rigidity.

Besides engineering the benefit of not having to get rid of the rear seats, this design is a significant improvement over Ford's original design for the Boss 302. Our X-brace mounts to the rear shock towers instead of attaching to the sheet metal behind the rear seats. This design is more effective and distributes the loads between the rear shocks, springs and the chassis, and not just the sheet metal of the vehicle. The result is much more effective chassis deflection reduction with improved suspension compliance over a sheet metal mount design.

This brace can be used as a bolt on installation or welded for maximum effectiveness.

Note: Does not fit convertibles or vehicles with Shaker/Mach 1000 stereo systems.

Product Benefits
  • Allows the rear seats to be retained!
  • Much more effective than other designs
  • Bolt on or weld on installation

CA Residents: Cancer and Reproductive Harm WARNING

Hi everybody Brian from spotlighting our Rear Seat X-Brace to stiffen up the chassis of your S197 Mustang Coupe. When Ford was developing the S197 chassis, they're really under a lot of pressure to do a few things. Bring a fresh looking car to the market as well as one that offered some more creature comforts as well as space. Let's face it some of the earlier cars the trunk space wasn't all that great and as the evolution of the Mustang was happening so are the clientele interested in buying such a car. We're talking about the chassis and how to improve it because we know that you want more from your car from handling standpoint and a predictability standpoint and an accelerating standpoint. So this is one of those items that will help improve the feel of the car and the performance of the car. For our enthusiasts out there the solution is the Steeda Rear Seat X-Brace. Now we offer two versions of this X-Brace. One that replaces the rear seats. You actually have to remove the rear seats. We do recommend if you can find a Boss 302 rear seat delete or get one from our friends over at CM Components which we offer as well as one that mounts in the trunk. So if you want to retain the rear seats. If you've got kids that you have to take along on your commute sometimes, we have one that also mounts in the trunk. Now it's important to know that the downside to this. If you even want to consider this a downside, that pass-through that Ford spent all that time putting together well it's no longer going to quite work like that. Obviously, you have room around this thing but it is going to limit that a little bit but the plus side, the plus side is in chassis rigidity. It's going to stiffen up the back of the car first. This is going to give you much better feel on what's going on behind you and that's important in a Mustang especially if you put some power adders into it or simply enjoy canyon carving or taking it to the track or autocross course. Likewise, if you're drag racing you're going to get a much better feel about what's happening with the rear end as far as Wheel Hop. This is why Steeda obviously offers many Stop the Hop components. Something that goes really well along with this brace even if you're planning to leave the suspension alone are our Subframe to Torque Box Connectors also for the back of the car. Between these two things dramatically changes the feel and performance of the car. It stiffens up the chassis. Now the other reason that this is so important in stiffening the chassis and you've heard about this for years and years and years. A stiffer chassis means that you can run a lighter spring rate. Means that the suspension isn't called upon to compensate for chassis flex. So by stiffening up the chassis you can run a more appropriate spring that matches what it is you're using the car for. You don't have to offset or compensate for a chassis that's twisting under hard cornering or hard acceleration. Installation is really straightforward and as we noted a moment ago if you do the version that replaces the rear seat you will want to have a rear seat delete kit. Some trimming of the panels is going to be required but realistically everything is reversible you can put the car back to stock if you choose to or you can get the trunk mount version which literally mounts in the trunk. The downside to this is well you don't get to see this pretty piece every time you get in your car. The Steeda Rear Seat X-Brace is offered in a few configurations. In addition to the trunk mount version that you see here, we offer three versions that replace the rear seats. One that's black powder coated like this with the CNC plate, another that's black powder coated like this with no plate in case you want to do something custom. If you go to the next level we offer one that is bare metal with the CNC plate so you can finish it off however you want. This is a good opportunity for you to tell us what color would you get your X-Brace in? To recap the Steeda Rear Seat X-Brace is going to benefit you these ways, It's going to stiffen the chassis. You're going to have better feedback with what's happening behind you. You're going to have better responsiveness from the back of the car and improved handling. We proudly manufacture this in the USA at our Valdosta Georgia facility because Speed Matters. if you enjoyed the contents of this video please click like and be sure to share with other Mustang enthusiasts. Follow us on social media to learn about these products and many of the other great things we offer. You can also visit us at Thank you very much for watching this video and have an awesome day!
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Fitment & Features


Manufacturer: Steeda Autosports
Made in USA: Yes

Installation Information:

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

Vehicle Fitment:

Fits Model Year: 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014

Customer Reviews

Rating Snapshot

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Average Customer Ratings


Opened box one tap was a little bent,all good once installed it straightened right out took about 2 hrs to install, definitely can feel the difference in in the ride
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Don't hesitate to purchase
If you like driving your Mustang hard in corners and don't want that extra Flex don't hesitate to purchase this x-brace this has to be the best one on the market also had mine powder coated to match the rest of my parts thanks steeda for the awesome product
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Great F*ing Brace
Totally great buy with a night & day improvement in the twisties. You won't feel too much in city driving except the noticeable decrease in creaks and vibrations over bumps. The improved handling gives you a more confident and planted feel. As for install, it's a whole lot easier to fold the back seats down and lay on top of them when doing the top brackets, personally. Even when hung over on a Saurday morning, I had it installed in 90 minutes from opening the garage to closing the trunk after taking pics. I say this is a must have for anybody serious about taking corners at speed.
Did you find this helpful?  9 of 10 Found Helpful
Awesome product, even better customer service
Great design and appearance. Definitely felt the stiffness increase in the body. Super thankful for the customer service as well. My package was delivered to the wrong address, and a rep called me and helped coordinate and solve the problem that wasn’t even their fault!
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Another GREAT part from Steeda
Another GREAT part from Steeda. It really stiffens the car up, The suspension works SO much better, It feels like a different car with the X brace and the Torque Box/Frame rails stiffeners. People, Have this installed in you car, you won't be sorry.
Did you find this helpful?  11 of 12 Found Helpful
Fits perfectly
Fits perfectly. I had it welded in for maximum performance and stability. So far had it installed for a week without any issues. The X-Brace does exactly how it should perform; stiffens the rear not on straights but on turns. It also helps with stability on bumpy roads creating a smoother ride and less interior noise.
Did you find this helpful?  14 of 14 Found Helpful
The X brace is one of the best mods I've made
I've had the best luck with chassis and frame stiffening. Each mod I've done has benefited both handling and ride compliance. The X brace is one of the best mods I've made. The interesting thing is, in addition to the improvement in ride compliance and handling that the steering has gotten lighter in a good way. Steering response has improved and I believe the lightness is possibly because the steering rack is not fighting chassis flex, it's more direct to the wheels now. Also, I have an aftermarket sunroof installed that had an occasional small creak going over curbs and now that small creak is gone, again probably due to decreased body twisting over curbs. Greet mod, should be first on the list for those who want to improve chassis rigidity. Also, it's great to still have the back seat. I have a 2014 pony package v6
Did you find this helpful?  4 of 5 Found Helpful
It's a different car.... unbelieveable
I have had this brace in my garage almost a year, dreading to install it because I am not little, and I knew I had to crawl in that little trunk of my 2012 Boss. I am sorry I put it off, it really wasn't that bad. I'll tell you if you have Coilovers (I have Penske Double adjustable) you have to reinforce the rear chock towers. It's a different car.... unbelievable. It may be my imagination but it even shifts better.
Did you find this helpful?  5 of 5 Found Helpful
'13 BOSS Complete
This was the cherry on top of the sundae! Super easy install. I decided not to cut the side-carpet, but instead just rolled it inward. Nice touch receiving a thank you card, too!
Did you find this helpful?  7 of 7 Found Helpful
Excellent bang for the buck!
Great fit and finish. Excellent bang for the buck! Was pretty straight forward to install. The directions were good. I can't wait to see how this effects the handling on the track!
Did you find this helpful?  3 of 3 Found Helpful
Maintains the rear seats!
Awesome, genius product! It really stiffens up the chassis and lets you retain your rear seats!
Did you find this helpful?  6 of 6 Found Helpful
What a great idea!! Add an x brace and keep the rear seats!! Yes please! Great price for the convenience of keeping your rear seats. Oh yeah and the handling is great!lol
Did you find this helpful?  6 of 6 Found Helpful
The icing on the cake
I have a lot of Steeda suspension parts on my car and this just tops it all off. I feel like it completed my handling project. The shipment came fast and when I opened it up it was beautifully designed. Thanks for an awesome product!
Did you find this helpful?  2 of 2 Found Helpful
Great Product!
Nothing but good things to say about this X-brace. Great quality, installed easily, and I can definitely feel the handling improvement. Plus, it was a great place to mount my custom stereo amps!!! Lastly, great customer service.
Did you find this helpful?  3 of 3 Found Helpful
Fantastic Purchase!
This is a great product and what makes it better is that it looks great when you open the truck and you keep the back of both worlds. install was a little tricky and I would suggest air gun to removed the shock nuts and might need a little larger drill bit to fit for the bolts (unless you are welding). it makes a huge difference in stability, plants the live axle on the ground at high speed turns. definitely worth the time and money!
Did you find this helpful?  3 of 4 Found Helpful
Great workmanship
Ok, finished my install on the X Brace...not a one hour job for sure. Although I must say it is an awesome piece of work that Steeda did with this brace. FYI, if you have the diff catch can, you will have to relocate. Regards, Manuel
Did you find this helpful?  4 of 4 Found Helpful
Huge Improvement
I can't believe how much this tightened everything up in the back of the car. It made a bigger difference than upgrading my rear sway bar. The back is firmly planted and steady in the corners. It even eliminated much of the clunks when driving over steep parking lot entrances. The install took 2 hours only because getting the nuts on the bolts in the limited space is tricking if you have small fat hands. I didn't have to use a jack as the brace slide right over the shocks without any problem. I can't think of a better upgrade to your suspension for the price.
Did you find this helpful?  6 of 6 Found Helpful
Great for the Rear
Adding this made a huge difference in the stability and response of the rear end. It made a much bigger difference than upgrading the rear sway bar.
Did you find this helpful?  7 of 7 Found Helpful
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