Prime Brakes? Are you about to change yours?

If you're about to change the brakes on your Prius Prime, let's talk.


I’ve had this idea brewing for over a year, and I’m finally putting it out there because the opportunity to collaborate with the right folks could lead to some really interesting findings. Here’s the premise:

Before you change your brakes, I’d send you an OBD2 dongle that logs all your vehicle’s data to an SD card. You’d drive with it for a couple of weeks before changing anything, then continue logging for a few weeks after the new brakes are installed.

Why? Because I’ve personally witnessed something on a 2013 Prius Plug-in that’s too interesting to ignore: using aftermarket brake components seemed to change the behavior of regenerative braking—it charged the HV battery faster than with OEM parts. Wild, right?

This could just be a fluke, or it could be a consistent and measurable difference caused by brake material, design, or pad friction. But until someone gathers the data in a controlled before-and-after test, we won’t know for sure.

So if you’re down to be part of this experiment, I’m happy to facilitate. I can help you set up the logging device, walk you through the process, and support a few different test paths depending on your interest and setup.

Let’s figure this out together. Who’s in?


https://black.jmyntrn.com/2020/11/19/toyota-prius-drilled-slotted-rotors-and-ceramic-brake-pads/

 

I have them shown in the image on the first first and linked to the blog article as well.

 

Appreciate both of y’all chiming in—MAX2 and Mendel, I know you're both knowledgeable and respected voices around here, so I’ll return the favor with some respectful perspective from a plug-in owner's seat.

Now, I get it. To the untrained eye—or non plug-in Prius driver—some of the stuff I’m saying might sound a little contradictory or outside the norm. But hear me out.

The experience I’m describing isn’t theory. It’s real-world, feet-on-the-pedals, hands-on-the-wheel experience—specifically in a Prius Plug-in, not a standard hybrid. That distinction matters. A lot. Because unless you’ve driven a plug-in Prius on cruise control at 67 MPH down a long, runaway-ramp-style grade (like the one I hit in Colorado), and watched your HV battery charge to 100% solely from the car managing its own speed using braking and regen, it’s easy to say “that’s not how it works.” But I’ve done it. Multiple times. No hill magic or unicorn power involved.

Now MAX2, you mentioned a contradiction in the article between increased grip and faster regen. I’ll say this: Just because something was designed for one purpose doesn’t mean it can’t yield unintended benefits in another area. That’s the nature of innovation. You can slap new pads and rotors on for better stopping power and suddenly—bam!—you’re getting a noticeable increase in regenerative efficiency because the system dynamics changed. Not despite them.

Mendel, I respect the clarification about brake pad friction not directly impacting regen. I do. But you’re talking theory. I’m talking practice. I’m not saying friction = more regen. I’m saying that post-installation of upgraded brakes (which included better bite and grip), my plug-in Prius was capturing noticeably more energy downhill than it ever did before. I was consistently seeing 0.7, sometimes 0.8 EV miles regained on a downhill I’ve driven for years—same exact route, same speed, same car. The only change? The parts. That’s not “writer’s logic”—that’s documented pattern recognition.

And here's the thing: how can anyone say “that’s not possible” without ever having tested it? We all love our data, but at some point, someone’s gotta challenge the data we’ve been spoon-fed for a decade. Everyone used to say never go over a 1,000-watt inverter or you’ll ruin your Prius. Guess what? I’ve been running two 2,000-watt inverters and haven’t even so much as made the car blink. So I learned the hard way—what “they” say ain’t always gospel.

If we shut down every observation that doesn’t match the script, how will we ever discover what these cars can really do? Heck, maybe I’m on the brink of unlocking one of the most slept-on aspects of Prius plug-in performance—and y’all are ready to toss it out because it doesn’t align with textbook explanations.

So let’s open the floor a bit wider. Maybe I’m wrong. Maybe I’m right. But let’s not dismiss real-world results just because they weren’t part of the factory brochure.

 

As I’ve gotten older, I’ve realized things don’t always work the way we were taught—or how Toyota writes it up in their limited literature. They don’t exactly hand us the secret sauce.

So if you're not open to thinking outside the box and at least considering the idea that maybe—just maybe—I’m onto something with this plug-in setup, then I can only imagine how interesting it’ll be when it turns out I was actually speaking facts all along.

I didn’t replace my brakes because the old ones were bad. They were in great shape. I replaced them proactively—over 150K on the car—because I wanted fresher stopping power to bomb down 4x4 trails like the Jeeps do. And after that, I saw noticeable, repeatable changes in regen behavior. Same route, same speeds, same driver—different results.

And look—remember when COVID first hit? We were told to wear masks, then not to, then back to wearing them again. Professionals, experts, entire institutions were flip-flopping—not because they didn’t know their field, but because knowledge evolves. So just because someone says “this is how it works” based on something they read or heard from a professor doesn’t mean that’s the only implementation or outcome.

There’s more than one way to skin a cat. And I might’ve just found one Toyota didn’t print in the manual.

 

See, this is the thing — you two can go back and forth with assumptions all day, but at the end of the day, unless you’ve actually done the upgrade, tested it, and seen the real-world results, what you're saying has no weight. It's all just hypothetical — correct me if I’m wrong.

Meanwhile, I’ve seen it, I’ve experienced it, and I have proof to back it up. That’s why I’m here — looking for other owners who are actually interested in testing and exploring this to find out if I’m right. That’s how progress happens. That’s how you prove — or disprove — theories.

Just tossing words around and playing with what-ifs doesn’t help anyone. So unless you’ve got something based on actual results instead of just assumptions, then honestly… it’s just wasted air at this point.

If you really want to know where I'm coming from, just go look at the threads I’ve started. I’m not out here posting for kicks and giggles — everything I bring up is something I’ve actually got my hands on and am actively working with or on...

 

with or without cross drilled and slotted? you wouldn't happen to have an obd2 dongle would you?

 

I gotta hand it to you — you really brought out the textbook energy with that one. “These are the basics taught in school”? Cool, but respectfully… this isn’t school. This is real-world application, and physics on paper doesn’t always translate the same when you're under the car actually turning wrenches.

I’m not working off theory — I’ve done the upgrade, driven it, tested it, and have seen the actual results to show. I didn’t just toss a diagram on a chalkboard and call it good. So while I appreciate the academic breakdown of how brakes and regeneration should work, I’m way more interested in what actually happens when rubber meets road.

And by the way, if anyone’s questioning whether I’m just throwing stuff out here for fun — feel free to look through my post history. I don’t post for clout or kicks. I post because I’m literally hands-on, trying new things, and sharing what works and what doesn’t.

No offense... unless we’re bringing something new to the table — backed by testing, data, or at least some wrench time — maybe it’s time to move on from the “back to school” speech. Cool? I say that as things that have been posted online and repeated like they are the true gospel... like lifting taller than 1.5" causes suspension issues or using a power inverter of more than 1,000W is bad for the Prius are just a few topics that from the textbook might have me aware of things to watch out for me ill say this there is a growing list of things I've been able to disprove that are these wives tales in the community. Personally when I see someone speaking text book and no hands on, I cant trust their words fully. Especially until I have hand me hands on it.

What I am proving is that with better aftermarket parts a PHEV owner could potentially achieve a higher MPG after installing brakes. I guess for me.. Id like to think folks would be eager to see this actually pan out versus using "textbook knowledge" to disprove someone's theory. This has me with a good question tho.... How could we use text book knowledge to theorize why what I observed actually happened? For me, the PHEV function has yet to be tapped into as most aren't like me and don't fear voltage shock.