We are test fitting GR Corolla suspension and brakes on a 5th Gen Toyota Prius Prime.
So, can it be done? Does it work?
You’ll have to watch the video to find out.
Welcome to the Bozi Breakdown. TTAC Creator Bozidar “Bozi” Tatarević is a Bosnian-American racing mechanic, writer, and technical consultant born in Sarajevo in 1986. After immigrating to the U.S. in 1995, he learned English in elementary school and eventually turned his passion for cars—fostered by his father Slav—into a full-time career. Laid off from a tech job in 2008, Bozi began wrenching professionally, eventually launching a shop and car export business with his family. His technical message board posts led to a writing career with outlets like TTAC, Motorsport.com, Road & Track and Racecar Engineering.
In 2018, he made his pro mechanic debut at Watkins Glen and now works as a tire carrier and mechanic for Vasser Sullivan Racing in IMSA, with 10 wins and a 2023 GTD Pro title. Bozi also consults via his agency Podium Prime, with clients ranging from race teams to media production companies.
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A transcript of the video, summarized by AI and edited by a human staffer, is below.
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Transcript:
Testing GR Corolla Suspension and Brakes on a Toyota Prius Prime
Today, we’re going to find out if GR Corolla suspension and brakes can fit on a Toyota Prius Prime. I’ve already removed the factory strut from my Prius. It currently has aftermarket lowering springs, but otherwise it’s stock. Next to it, I have a GR Corolla strut assembly from a low-mileage salvage car that I’ll use for comparison and, hopefully, a test fit.
At first glance, the two struts look dimensionally very similar. The top mounts appear almost identical. The biggest visible difference is where the spring sits—on the Prius, there’s some protection in this area, while the GR Corolla version is much more open. The mounting point for the anti-roll bar link is also different: on the Prius, it’s mounted closer in, while on the GR Corolla, it’s pushed outward slightly, which could change the geometry a bit. The mounting points that connect to the knuckle appear identical, but I’ll take measurements to confirm.
Starting with the knuckle mounting flanges:
The distance between the edges on the Prius version is about 50.19 mm, while the GR Corolla measures 50.21 mm—virtually identical. The opening size on the Prius measures just over 29 mm, and the Corolla version is 28.76 mm, a difference of only about two-tenths of a millimeter.
Looking at the top mounts, they also appear nearly identical. The main difference is in the mounting teeth design. Measuring from stud edge to stud edge, both come out just over 187 mm, so the Corolla strut should fit the Prius top mount without issue. Inside the top mounts, the GR Corolla’s design is solid, while the Prius version has gaps. There might be a small difference in angle, which we’ll verify during installation.
With that, it’s time to test-fit. I slid the GR Corolla strut into place, and the good news is that the top bolt pattern lines up perfectly. All three studs fit where they should. The knuckle connection was also a near-perfect fit—the slight measurement difference didn’t cause any issues. The bolts from the GR Corolla assembly match the Prius bolts in size, so I reused them without a problem.
The GR Corolla strut even includes the same clip to hold the speed sensor wire, and the brake line bracket lines up correctly. Everything fastens together as expected. It’s nice to see Toyota’s cross-compatibility at work here—likely a result of shared parts and supply chain efficiency across models.
Once everything was bolted in, I verified that the camber bolts matched and there was no interference. The anti-roll bar mount position might slightly change the ratio, but nothing looks problematic. With the wheel mounted, there’s no fender interference. The ride height is higher than before, so switching to lowering springs might be necessary to match the previous setup.
After letting the suspension settle, I took some quick measurements:
Ground to fender: 70 mm
Center of wheel to fender: 39 mm
Top edge of wheel to fender: 14 mm
Tread edge to fender: 9.5 mm
These numbers give a good baseline to compare once the Prius strut is reinstalled.
Next, I tested whether the GR Corolla brakes could fit. I used a GR Corolla caliper with a Yaris RC rally adapter, which is designed for rotors the same size as those on the Prius Prime. This should allow me to use the upgraded caliper without increasing unsprung weight. The GR Corolla caliper is about 4 pounds lighter than the stock Prius setup, which helps offset some of the added wheel weight.
The CarboTech custom pads I’m using are a mild street compound—ideal for the Prius Prime’s limited need for friction braking due to its regenerative system but useful for spirited driving. For now, I’m only doing a test fit since I still need to learn how to calibrate the electronic systems, bleed the brakes, and ensure everything communicates properly through Techstream.
The caliper mounted perfectly with the adapter, and the wheel cleared the caliper with plenty of space—better than expected. Mechanically, everything fits and works together.
After reinstalling the stock strut and lowering spring, I took new measurements for comparison. With the GR Corolla suspension, ground clearance was 70 mm; with the stock strut and lowering spring, it’s 66.5 mm—about a 3.5 mm difference. Other measurements:
Center cap to fender: 36 mm
Wheel edge to fender: 11 mm
Tire edge to fender: 6 mm
These comparisons suggest the stock GR Corolla suspension sits roughly where the stock Prius Prime setup does, giving me useful reference points for future modifications. Everything bolts up cleanly, so I’ll move forward sourcing GR Corolla struts with matching springs to fine-tune the setup.
