Lesson Learned: Keep your Brake Rotors Conditioned!

[strider]

Curious then Strider...why do performance cars like Ferrari, Aston, Porsche, etc use these massive calipers then?

Calipers on these vehicles seem to cover off about a quarter of the rotor circumference...when I had my Roadster calipers painted (red) a few weeks ago, I was shocked how tiny they look when compared to the above mentioned vehicles...is this just a (nother) thing to feel inadequate about?

Well, first off, these cars weigh more than a Roadster and so need larger brakes to slow them down. A 911 Turbo weighs 1,000lbs more than a Roadster. An Aston DB9 weighs 1,500lbs more than a Roadster. Even a 458 Italia weighs 600lbs more. There is also a factor of design/looks. People think large rotors look faster - more like a race car. Same reason Model S has 21" wheels. Not very practical but they look cool.

Also, this discussion is mostly about street driving. If you track your car you will have no problem keeping your rotors clean (the subject of the thread). Also in a track situation, larger calipers/rotors help to dissipate heat since there is more surface area both in the pad and rotor so lower temperatures. This keeps the brakes cooler and allows repeated hard stops coming into multiple corners per lap. So if Tesla, like Lotus, offered a "track brake system upgrade" then I would expect larger calipers and rotors. But if this brake upgrade is to solve the subject of this thread, the size of the rotors and calipers are adequate to lock up the wheels and therefore are large enough. We just need a rotor/pad combo that will have good initial bite even when seldom used.

[Jaff]

Sounds logical...thanks for the explanation!

[driver_EV]

Doug_G, what you say about hard braking makes perfect sense to me, and higher (maximum) braking forces at the calipers, that result from the conditions you describe (especially sticky tires) will heat up the rotors and pads dramatically. This is something that most of the Roadsters may never encounter in normal driving.

The particular benefit I see is from very high temps. The pads and rotors will cook/burn off any oil residue that collects from the leaky ICE cars on the road. Leaving them very clean to provide the maximum braking response you describe.

-good advice.


This brings to mind the issue of flushing brake fluid that is presented in another thread. The key reason to flush brake fluid is to eliminate the moisture that contaminates the fluid over time due to atmospheric humidity levels. The issue is that with a significant amount of water in the brake lines, combined with the very high temps at the calipers while under racing conditions, or other extended use of friction brakes, the water can turn to steam, displace the hydraulic brake fluid, and cause loss of any brake operation. Unusual conditions, especially for an electric car, but for ICE performance cars this is a safety issue, and is why manufacturers have a brake fluid flush interval. So you may want to pay attention to fluid quality with the braking system.

-Richard

[frequencydip]

I'm willing to bet the brake upgrade would contain a improved brake booster.

I would like to se an upgrade at least to the rear caliper to a two piston. A 4 piston upgrade to the front would also be nice. The discs on the car are sufficient but if they introduced lighter discs by using a floating disc that would be sweet. An all aluminum disc would also be nice but I hear aluminum squeals more than steel..

[DSA]

Short version:

To properly bed your brakes, perform a series of up to 10 60 mph to 10 mph stops where you are braking as hard as possible. Your brakes will be EXTREMELY hot after this and if they've never been bedded in before, they very likely will be smoking when you're done. DO NOT COME TO A COMPLETE STOP AT ANY TIME! If you come to a complete stop this will result in uneven pad deposits which can lead to "warped" rotors. Drive around normally for 10-15 minutes avoiding any complete stops to let the brakes cool off. The dedicated will repeat this another time!

-Warped- Brake Disc and Other Myths

Thanks for this detailed explanation - I was wondering how many hard stops would be about right for "one session" before things get too hot - it sounds like 10 hard stops should be about right. Rather than drive around non-stop for 10-15 minutes afterward, could you just stop and put on the parking brake for at least 30 minutes or so, especially if your hard braking session is close to home? That could let the brakes cool off without the pad in contact as well without having to drive non-stop for awhile.

[Doug_G]

Do NOT turn on the parking brake after bedding in. That could warp your rotors. In fact it's best if you could avoid using the brakes altogether until they've cooled off.

[drees]

Do NOT turn on the parking brake after bedding in. That could warp your rotors. In fact it's best if you could avoid using the brakes altogether until they've cooled off.

Yep. Not sure what the Roadster's parking brake is like - but just stopping the car will lead to uneven cooling of the rotors with the pads sitting over one spot which can lead to uneven pad deposits on the rotor.

If you do get uneven pad deposits on the rotor which will make the rotors feel warped, another bedding session may fix it, but worst case you'll need new rotors.

Don't risk it!

[DSA]

Do NOT turn on the parking brake after bedding in. That could warp your rotors. In fact it's best if you could avoid using the brakes altogether until they've cooled off.

OK, good thing I asked. I did a session with ten hard stops to break in the brakes earlier today and drove around for a bit afterward to let the rotors cool. The brakes are now much less noisy than they used to be, but I think I need at least one more session to get them where they need to be.

[goyogi]

GM uses special rotors on the Volt. I gave my Volt the semiannual car wash yesterday (wow, it looks nice when washed! and found very little brake dust and a corrosion free rotor.
http://www.propickupmag.com/gm-desig...e-wear-issues/

[Doug_G]

My Ranger did brake service today, as part of the annual. I was rather surprised by just how tiny the front pads are. The ones in my S2000 are twice the size! The S2000 only has one piston but has a heck of a lot more stopping power (the first time I tried a harder stop with them I unintentionally locked the wheels, because I pressed the brakes like I do in the Roadster).

I'm now thinking that the problem with the Roadster brakes, aside from crappy pad material, might just be insufficient margin. They're fine when they are sparkling clean, but a little bit of crud, glazing and corrosion renders them inadequate.