This article describes how I installed the GReddy rear upper strut tower bar trunk brace for the 2005-2010 Scion tC. I didn’t find much info on this install so here’s how I winged it.
Where did I find it?
I found this bar on the Facebook Marketplace. I paid $120 for it. It was in decent shape. I’ve seen worse. Best I can tell the original part number SKU is 14013032.
Advantages of rear strut tower bar
A rear strut tower brace is a simple but effective upgrade that delivers noticeable improvements in handling and chassis stability, especially on unibody vehicles. By tying the tops of the rear strut towers together, the brace helps reduce chassis flex that naturally occurs during cornering, acceleration, and uneven road conditions.
One of the biggest advantages of a rear strut tower brace is improved handling consistency. When the rear suspension mounting points flex independently, the suspension geometry can change slightly under load. A brace minimizes this movement, allowing the suspension to work more predictably. The result is a tighter, more planted rear end—particularly noticeable during aggressive cornering or quick lane changes.
A rear strut tower brace can also enhance overall vehicle balance. While many drivers focus on front-end upgrades, stiffening the rear helps complement front suspension mods like sway bars or coilovers. This can reduce body roll, improve turn-in feel, and make the car feel more composed through corners.
Another advantage is the ease of installation. Most rear strut tower braces bolt directly into factory mounting points with basic hand tools, making it a relatively easy DIY installation.
Installation
I had to line up the tabs and cut the carpet. Here’s how I lined up the tabs against the carpet. There’s some eyeballing involved.
1. Hold the bracket against the side panel, but pull it out, align the bolts as best you can. We’ll mark a reference point with a utility knife as show below. You are marking the top of the cut, then will cut downward from here.
cutting slits in the carpet for the Greddy rear strut tower bar bracket
trimming the cloth to install greddy rear strut tower bar bracket
2. Now we mark the other side of the bracket. To get the width right, rotate the bracket (shown below), then push the ears up against the trim, and then mark again with your utility knife.
3. There is a contour in the paneling where you will cut down to, best pictured here. I then used sharp scissors to cut through the paneling and create about a 1/8″ slit for the tabs. Just eyeball it. Remember, take a little off at a time and test fit. You can always trim more off if needed. You CAN’T add material.
cutting slots in the carpet for the greddy rear tower bar bracket
Now pull the panel back, shove the bracket on the strut bolts, and feed the ears through the new slits you cut. Trim additional material with the scissors as needed.
poke greddy bracket tabs through carpet for clean install
Repeat for other side. You can see here I cut too high on the passenger side, there’s about 1/4″ gap
cutting through hatch carpet trim for Greddy rear tower bar install
Button everything down:
greddy rear strut tower bar clean bracket install
Greddy rear strut tower bar Scion tC 14013032
Greddy rear strut tower bar 2005-2010 Scion tC
Other info
If you’re trying to track down this bolt, it’s an M10-1.50 thread. 65mm length allen (hex wrench) head. Here’s a link to the bolt thread checker tool I use.
Greddy rear strut tower bar bolt is M10 1.5 thread
Greddy rear strut tower bar bolt replacement M10 1.5
Greddy rear strut tower bar install carpet cut
Greddy replaced hex bolts with black flanged M10 1.50 65mm bolts
Final thoughts
Some people will say this doesn’t do much for the Scion tC. Since I was a late bloomer, I personally like finding hard to find parts for the Scion tC. The only thing I don’t like about this design is that it’s not a fixed bar, there’s potential for the bolts to loosen or back out over time.
Other manufacturers of rear strut tower bars for 2005-2010 Scion tC
I share maintainence and upgrade info for the 2005-2010 Scion tC platform. I also showcase tool reviews, restore projects and custom modifications to inspire other DIY enthusiasts.
