Installation on a Mazda MX-5 (Miata NC)

Before we consider posting any articles that are found on the net, we do our research. However, this post was pretty harsh on what to expect from the Ultra Racing braces. He did keep a few pieces granted he got them for free as a test vehicle. 

The post was written March 11th, 2010 by GarnetMica

The first item installed was the upper rear two point brace identified as UR-RL2-791. 

There are two 17mm nuts that require a deep socket wrench to remove. Once removed, the bar slides into place and the existing nuts were reinstalled. The fit and finish of this piece was excellent. The install was straightforward and easy. The time to install was approximately 10 minutes.

*Installed:

The second and third items installed were the lower rear two point brace identified as UR-RL2-790 and the two four point braces identified as UR-RLS4-789P. 

In order to install these parts, you need to remove two small black braces that attach from the rear suspension subframe to the rear body. There are three 17mm bolts in each. 

Once those are removed you will need to remove one additional 17mm nut and 17mm bolt from the body on either side and the rear 12mm bolts on each side of an existing aluminum x-brace. The side braces (UR-RLS4-789P) are then bolted into place using the existing 17mm hardware on the existing attachment points. 

The 12mm bolts at the aluminum cross brace are replaced by 13mm bolts with a small and large washer. During the install, we noted that the brace seemed to be under tension towards the front of the brace. The cups that that secure the brace to the chassis seemed very thin and the welding of the cylinder to the mounting base seemed a bit sparse. I was disappointed that the the brace lacked a tube that bisected the open box turning the side braces into more stable triangles. I'd like to note that in preparation for the install, I researched a number of aftermarket and factory brace, all connect these two points directly. The removal and installation took about 20 minutes each side.

*Installed:

*Below is a photo of a MX5 rear suspension. The braces as little black reinforced frames that go outward at about a 45 degree angle and are attached by three bolts each at the bottom of the photo:


Once the sides were complete I installed the lower two point cross brace UR-RL2-790. This installation was straight forward and easy. Since everything was removed to install the side braces, this installation took less than 5 minutes.

*Installed:

The side braces attach existing structure points together but I am concerned that they may lack the directional strength of the OEM brace. Part UR-RL2-790 is effective in building a box under the diff. After the install I took the car for a test drive and immediately noticed a slight groan in the rear chassis that was not there before. It happens in offset speed bump crossings. Immediately my mind jumped back to the absence of a brace connecting the two factory points between the rear sub frame and body. 

I may remove these pieces (UR-RLS4-789P) and reinstall the existing OEM brackets but that means I will no longer be able to use the UR-RL2-790 two point bar because the OEM bracket is shaped in a way that prevents the UR piece from installing over it.

We then moved to the front braces. The first to be installed was the smaller part identified as UR-LA4-787. This required removal of a 17mm an 19mm bolt from each side. The install was the same as above. The fit and finish of this bar was pretty good. The mounting tubes are still a bit thin but the piece was being added to an existing OEM brace so it will still add to the strength of this area. The install took approximately 10 minutes.

*Installed:


Next we prepared to install the larger of the two braces, UR-ML4-788. The brace calls for removal of a large factory cross brace that crosses under the engine. It appears based on the photos from the UR website, the large "lightweight structure" needs to be removed. 

Again nearly all aftermarket and factory enhanced braces avoid replacing this piece or replace it with more robust parts. Replacing this part with the comparatively thin Ultra Racing tube again seems like a downgrade from stock and the lateral bars will likely do very little to strengthen the chassis in this area. We decided to not install this piece. 

Pics of the install:

Source: https://forum.miata.net