What really is the difference between the brake discs, callipers and pads?

[dandrewk]

Honestly?

Because most people don't understand how brakes work and think "sports cars have big brakes, big brakes always better!"

Which is not, at all, true.

They also do offer some benefit on a race track where you're braking from 100+ mph over and over again without cooling the brakes off.... but most owners will never do that, so mainly it's the first reason.

Confession. I was playing a bit of "devil's advocate" here. The purpose being the question asked many times in this forum: What -is- the real difference between P and Stealth? Another topic here has a long, often heated debate regarding the difference (if any) in the traction motors. I think the principal reason Tesla puts beefier brakes on P is -because- of the larger tires/rims. That combo is considerably heavier than 18" tires/rims, and (ironically) the brakes themselves are heavier. You need bigger brakes for a heavier vehicle.

I have a Stealth in pre-production, and like many feel it's the best value for Model 3. The biggest advantage of the P seems ti be the tighter suspension, which along with the 20" tires would translate to better handling on curvy roads and the track. As I don't plan on visiting Sonoma Raceways or Laguna Seca (got my fill of that with motorcycles), the Stealth was a no-brainer. Having a quieter ride and fewer flats is a bonus.

 

[m3-ricardo]

the performance brakes vs the awd brakes ..

as someone who has tracked cars before, with stock break setups and aftermarket ones.. -- the difference is most noticable at the track.

bigger breaks means that you can stop harder more often -- brake rotors with slots or holes can dissipate more heat.

for street cars, the ugpraded brake packages usually cause more trouble than they are worth ..

upgraded pads wear faster, wear down rotors faster, cause more brake dust, are noiser (squealing), etc, etc.

but if you are going to put your car on the track, you want to upgrade some of the brake parts or the whole pacakge, and you must also take good care of them to avoid warpage, etc.

when i was doing track days with my street car, you would drive to the track then ..

1 - adjust suspension (had adjustable konis)
2 - change out pads on stock brake calipers, and upgraded slotted rotors. -- that was enough to improve fade, and i was too cheap to put aftermarket calipers.
3 - change out tires for performance tires

throw in some frame stiffening parts -- and the car would behave radically different on the track.

 

[Sophias_dad]

My understanding was also that while a tire is skidding, it is actually slowing the car less than when it is not.

Yes indeed, particularly in non-dry conditions....

Friction and Automobile Tires

 

[DopeGhoti]

So short version, all you need out of brake pads, calipre, and rotors is the ability to grip the rotor more firmly than the wheel grips the driving surface; and the ability to either stand on the brake to leverage ABS or to modulate pressure to get the ideal friction point just on the grippy side of a skid.

 

[Knightshade]

So short version, all you need out of brake pads, calipre, and rotors is the ability to grip the rotor more firmly than the wheel grips the driving surface; and the ability to either stand on the brake to leverage ABS or to modulate pressure to get the ideal friction point just on the grippy side of a skid.

Yup...or as the pulp friction article puts it-

You can take this one to the bank. Regardless of your huge rotor diameter, brake pedal ratio, magic brake pad material, or number of pistons in your calipers, your maximum deceleration is limited every time by the tire to road interface. That is the point of this whole article. Your brakes do not stop your car. Your tires stop the car. So while changes to different parts of the brake system may affect certain characteristics or traits of the system's behavior, using stickier tires is ultimately the only sure-fire method of decreasing stopping distances.

 

[Big Earl]

Driving around town or on regular highways is one thing. Brake size doesn’t matter in those situations. When on the track or doing high speed driving on the Autobahn involves frequent stops or slows from high speeds. Try to go 150 to 70 a few times in a row with the regular brakes and you’re going to cook them. OP specifically mentioned high speed driving in Germany, which could use beefier brakes to deal with the additional heat from high speed brake applications. Bjorn has some good videos on YouTube.

The question is not about stopping power. It’s about stopping consistency and repeatability in high performance applications.

 

[DarthPierce]

I'm no autobahn expert, but I did spend 10 days there last month, and did enjoy the unrestricted speed zones getting my rental SR+ model 3 up to ( and beyond??) its maximum speed of 230kph (143mph) on multiple occasions. Only once in 10 days of road-tripping on the autobahn did I hit the brakes hard enough to come close to the ABS threshold. The VAST majority of the slowing for traffic needed on the unrestricted autobahn was handled just through the high regen.

In my experience (limited though it is) you're looking at ~1 panic stop from high speed per 1500km. That's way more than plenty of time for them to cool off and avoid brake fade. The only time you benefit from "performance" brakes is on a track. (Admittedly the Nürburgring in Germany is technically both a track and public highway, so I'll say that's the only time you could benefit from performance brakes on a public road)

 

[DrtyJrze]

In my experience (limited though it is) you're looking at ~1 panic stop from high speed per 1500km.

I think you got lucky, because when I was there I saw multiple people jump over into the left lane and cut someone off that was moving. Actually saw a few vans do it.

IMO I don’t think people were doing it on purpose, but when you’re doing 160+ you come up on drivers FAST. People can’t assume when you looked 5 seconds ago that a car isn’t there now.

Still the greatest roads in the world though. I wish we had something like that in the U.S

 

[jipvk]

The roads in the Netherlands are better I must say, made of semi porous material so it stays dry when it's raining etc. The problem in the Netherlands is, is that it is a lot more busy than in Germany. And no unlimited speed.

But I think many people who don't drive in Germany often can't understand how much more 'aggressive' braking you do on the autobahn than on the interstate in the USA. Also having better braking feel because of the bigger callipers is worth it. Well applied braking power that will remain the same over and over again is totally worth it.

If you're doing 200km/h or more on a normal cruising speed, it's quite dangerous when the hot blonde girl in her VW Up just goes to the left lane to overtake a truck without checking her mirrors because she's too busy to do her hair using the rear view mirror. This happened to me before and I was lucky my BMW slowed down as quick as it did.

I didn't come here to ask opinions wether it's worth it or not... I mostly came here to get specs differences on the brake systems.

Rotor size difference? Brake pad size difference? etc.

(Message comes of a bit as aggressive I don't mean it like that, I appreciate the talk here in the thread.)