Review & Install Video
Hey, guys, Stephanie with americanmuscle.com, here with an overview of this IRS Cradle Bushing Lockout Kit from BMR for the 2015 and newer Mustang. In this video, we're gonna discuss what this kit does and how to improve things for your S550, the materials and construction, and, of course, the install, as well. I'll go into more detail later, but the install for this kit is easy and it's a one out of three wrenches in the difficulty meter. The BMR IRS Cradle Bushing Lockout Kit is gonna be something that you should check out if you're looking for a way to combat some of the notorious wheel hop issues that come along with an IRS.
The S550 is known for wheel hop, bushing deflection, and cradle movement, so BMR has designed this kit to combat all of that and keep the cradle centered under the car at all times, making for a big improvement in handling performance. So, if we talk generally here, and don't get into too many fine details, your differential is surrounded by and supported by your cradle.
The cradle is the heart of the rear end and the IRS suspension, and there are a lot of components that touch the cradle. Now, of course, as usual, soft rubber bushings are used in the cradle, and Ford does that because they have very high standards when it comes to NVH, or noise vibration and harshness. The soft rubber bushings are needed to tune out bumps and give the ride quality that Ford wanted from this car. This means that there are soft rubber bushings that are isolating the IRS cradle from the chassis, which makes for a prime atmosphere for movement. When the cradle moves, that's when you get your dreaded wheel hop, and, of course, when the cradle moves, the geometry of the suspension changes, which is less than ideal if you're trying to hook up, drive spiritedly, or race your car.
With all that in mind, BMR developed this kit as a way to kill off a lot of that wheel hop without having to replace the stock bushings and without adding a lot of unwanted NVH, because let's face it, the struggle is always finding that balance between creating an effective suspension that doesn't ride like crap. This kit has a few different components, but what you're looking at here, are lockout brackets, front, upper, and lower spacers, and rear, upper, and lower spacers that are made from billet aluminum and stainless steel and heavy duty one and five-eighths inch steel tubing.
The upper bushing lockout rings are billet aluminum and they're made to combat the area of the inner bushing sleeve, both front and rear and the outer lip of the bushing cup on the cradle. The lower bushing location washers handle the bottom portion of the bushings' inner sleeves, and this means that both parts of the bushings' inner sleeves are taken care of. This is gonna combat nearly all of the movement, no matter what type of movement in the cradle. Then the cradle braces are gonna replace the factory sheer plates that keep the cradle centered perfectly under the car, and these bolt directly onto the frame to make sure the location of the cradle can't change no matter what.
Of course, BMR fully tested and documented their testing of this kit. What they're noting here is no change in NVH and an 80% to 90% reduction in cradle bushing deflection. Now, a completely stock car with stock tires is gonna see a higher percentage of reduction, while you guys running sticky tires will see a little bit less of an improvement, but you're still gonna be within that 80% to 90% range. Either way, those are huge improvements, which means that this kit and this kit alone will go a very long way in reducing wheel hop in the S550, with 100% bolt on kit that keeps the stock bushings and doesn't add NVH.
When it comes to price, you can expect to pay right about $200 for this kit. BMR does sell some components separately if you didn't want to go for the whole kit, but I will say right now that this kit is gonna be the most effective for you. In all honesty, it's not very expensive. You can always just tackle the differential bushings if you wanted to, but this kit saves you from having to do that.
Moving on to the install, like I said earlier, this is a direct fit kit and you aren't replacing any bushings here, so the install is going to be straightforward and simple. You're looking at an hour or two, tops, in the garage and a one out of three wrenches in the difficulty meter. The job can be done on jack stands if you don't have access to a lift, but as always, a lift would make things easier for you, as long as you have a way to support the cradle, since it will need to be dropped.
I'm gonna glaze over the details here, but BMR does give you an illustrated guide to help you with the install. Your rear wheels will need to come off, and the cradle is held in by four bolts. Once the cradle is unbolted, you'll need to lower it down to make room to insert the upper bushing cup. The cups go over top of the bushings and the cradle goes back up into position, but don't bolt it down yet. The lower front spacers go over the bottom of the front bushing and the cradle supports can be lined up. Once you have all of this lined up, you can make the cradle flush with the frame and tighten the main bolts down. Before you really tighten everything down though, you will need to make sure that the cradle was centered, and BMR will tell you step by step how to do this.
Wrapping things up with the BMR IRS Cradle Bushing Lockout Kit, this is a kit that's designed to eliminate nearly all of the cradle movement that causes wheel hop in the S550, without having to replace the factory cradle bushings. The kit has a few components that are gonna address any and all possible movement in the cradle and keep it centered under the car at all times no matter what. As always, I suggest you check it out more online for yourself. And for all things Mustang, keep it right here at americanmuscle.com.