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                 Z4 Rear Strong-Strut Brace

                                The 2007 ///M Roadster pictured here belongs to the Strong-Strut principal owner, Paul Ebeyer



Z4 rear brace replacement by Strong-Strut 

  see many photo's below

read customer testimonial here

Unfortunately, the rear, factory, bracing bars attached to the differential and the rocker panels are terribly inadequate. They are made of a thin, soft, hollow,  material which offers very little resistance to the forces applied to it, we have solved that problem through the use of  carbon steel. There is so much flex in the soft, OEM brace, BMW found it necessary to include an extra brace ON the brace so it wouldn't bend as much. (brilliant, a brace on the brace, why not make it correctly in the first place?)

Many Z4 owners recognize the need to replace the OEM braces with something that is substantial and considerably more effective and we, at Strong-Strut agree.  The new Z4 rear Strong-Strut bracing set does for the rear of the chassis what the front Strong-Strut does for the front of the chassis, it substantially increases rigidity to the rear chassis and provides the many benefits that come from less chassis flex. We have drawn upon our ten years experience with the Strong-Strut Body-Brace that has been so successful on the BMW Z3 chassis, and since it is a proven and thoroughly tested design, we have utilized the identical material and basic design in our new Z4 rear brace. The Strong-Strut brace material is hot rolled carbon steel angle iron with legs that are 1 and ½ inches wide and ¼ inch thick. The web, at the point of the “V” which takes the stress, is a full 3/8 inch thick. The end materials are cold rolled 1031 steel of 3/8 inch thickness that begin as billet material. The brace is installed in the “V” configuration with the bottom of the “V” toward the ground and the upper, open side against the underbody of the chassis. There is no “mid bracing” required on our product and when you hold it in your hands you will understand why there is absolutely no flex or movement possible. Installation is a simple bolt on replacement procedure. You will have to elevate the rear of the car to install it but the actual replacement with simple tools is no more than a 30 minute task. Simply remove the OEM brace and use the same mounting points and hardware along with provided spacers, to install the Strong-Strut Z4 rear brace.  The installed braces add only nine pounds over the OEM braces and we are told by a highly experienced 06 Z4///M driver, a died in the wool track junkie,  that traction at the rear of the vehicle benefits from the extra weight. The set of two braces are designed so road debris or moisture cannot get trapped in the "V".

One more comment because someone raised the question on one of the Z4 forums. The Strong-Strut rear brace will not cause the rear of the car to break lose any sooner than a stock setup. The Strong-Strut rear brace is NOT a suspension component, it simply reinforces and adds rigidity to the rear section of the chassis. Some people are confusing the Strong-Strut rear brace with a stiffer rear anti-sway bar, which, under some circumstances, may make the rear end a bit loose.

 OEM braces shown below                                   a brace on the brace                                               OEM as factory installed


  below, Strong-Strut production version complete units                                                                                                end pieces


end piece attachment point                                                                                 Installed on owner's 07 M Roadster



                  End  pieces, development process                                                                          Strong-Strut Machined end pieces


 individual parts of Strong-Strut brace assembled for display                           3/8 inch thick steel end plates CNC machined