BRracing BMW 135i rear strut bar, harness bar

After our work on our BMW E46 M3 rear strut bar, harness bar, and our MINI rear strut bar harness bar, we took all that we learned from those, and applied that to solve the same need for our BRR Project 135i car.

The result is a complete bolt-in rear strut bar, harness bar, down bar/x-brace solution, that provides the connection and protection we needed for the track day activities, as well as allowing the solution to enable us to continue to use the car and the REAR SEATS on a daily basis.

BRracing introduces it’s new rear strut tower bar/brace, and harness bar with integrated down bars and x-brace.
With all of our recent track work and track testing, and prior work on our E46 M3 and MINI MCS, we both needed and realized the need for an integrated harness bar and strut tower brace. But….this is our daily driver, and we wanted the solution to meet all possible customer needs for a combination daily driver and track car (not race car…track car mind you).
To that end, the requirements for the daily driver are that the bar needed to allow for the CONTINUED USE OF THE REAR SEATS all the time when we’re NOT at the track, and to not interfere in any way for the rear seat passengers. We also needed the complete solution to be “BOLT IN”, so that no new holes or attachment points are needed at any location. We wanted to use the strongest mounting locations to provide for the strength and rigidity, but not throw out the other requirements. We wanted the rear shock tower brace to both work for the harness bar attachment, strength, and torsional rigidity, but not interfere with the use of the trunk, but also meet the needs of strengthening the rear shock tower and body area. We needed the rear down bars and x-brace to be EASY TO REMOVE, but very strong, and EASY TO INSTALL (takes less than 5 minutes to do either). We wanted the completed product to look factory in all ways, including the clearances to the roof liner and side B-pillars.
And…we think we have it. This approach allows for the implementation in multiple configurations and upgrades.
You can start with just the rear strut tower brace only.
You can then add the complete harness bar. You can run with just the main hoop and rear strut tower brace, and then, when going to the track, pop in the down bars/x-brace, and also the main harness cross bar. We even added a little set of extras, like integrated attachment points for the lower harness connections on each side.
The main bar has a massive plate on the bottom, and uses both the side seat belt mount hole in the side rail, and the hole in the bottom floor pan that is over 4″ away from the side rail, and in this manner, provide the strength required….plus the base plate is so thick, that you would have to crush the whole car to get the hoop to crush thru the floor pan. The rear strut brace uses two existing rear bulkhead mounts, that have already been strongly reinforced by BMW in the car, for the main attachment points. Again, no new holes, but incredibly strong attachment points. Plus, the rear strut bar sits so low, and forward in the trunk, that the complete trunk area is still usable, and you can even stow your skis and other things w the seats down. We even made sure visibility from the front seat is unobstructed thru the rear x-brace.
Testing…we’ve only done the first set of tests, but we can attest that the whole assembly does significantly add to the torsional rigidity of the complet e car, as we almost couldn’t get into a steep driveway that we’ve driven into before, as the car lifts that much now due to the stiffness.
You can get the bar(s) in almost any powder coat color you want, and not have to pay a fortune to get the whole thing.
And, for those that want to know, the whole solution is made of the following –
1.5″ x .095″ 4140 chrom moly tubing
chrom moly clevis mounts
Grade 8 and above metric hardware
Full TIG welding on all attachment points (tolerances are tight, welds are beautiful)

Pricing is as follows –
Rear strut bar only (in any powder coat color) – $300
Complete rear strut bar and harness bar assembly – $1,200 (if you want this, just be prepared to sign a bunch of disclaimers for insurance liability reasons)

Pics –

Call us at 408-356-1515 for ordering details and color selection, or email us at brracing@gmail.com

Thanks for all the great comments and responses….love the input.

We also got a lot of requests for clarification on the rear shock tower mount, bulkhead mount.  So, with the installation in another customers car just completed this weekend, have taken some additional pics to show the innovative approach.  Still is complete bolt in, leverages the strength of the rear bukhead area and additional body supports, and also the bracket itself is mounted such that the base is against the cross bulkhead, such that should there ever be force from the down bars/X-brace, rather than the bolts being the clamping force that prevents twisting of the mount, the mount itself uses the body to prevent this, giving the result of being completely tied into the body.

And, as reported in the 1Addicts forum, we have seen real results in torsional rigidity w this new solution on the track…come on out and play w us.