STOP! Read this before you buy your next set of performance brake pads...
January 22 2018
So you’re looking at buying brake pads, or thinking of what it would be like to feel different pads in your car, and you’re a little lost with all the names, terms, and marketing data? I’ve been there, more than once actually. Every car I’ve owned has gotten more power, lighter weight, and better cornering, but what happened when I press my brake pedal? Often not everything I needed. So where did I go wrong? How can you know which brake pads are right for you? I’ll try to keep it simple, I’m no scientist or professional racer, but I can tell you I’ve tried enough pads so you don’t have to!
Street/commuting driving is where most of us spend our time. What is important in a street car? A few things come up that you might not expect. For one, the brake pads can’t lose all friction at a cooler temp right out of your driveway, but also can’t be too dynamic and grab extremely hard under moderate braking in traffic. You need something consistent, and predictable, along with a safe friction level at all circumstances. This can include alternative weather conditions as well. With a streetcar, you will want some long lasting pads too. Nothing is more difficult than opening up your wallet to buy the same pads over and over because they wear too quickly. On the flip side, you don’t want too abrasive of pads that cut into your expensive rotors either. This delicate balance often correlates to friction levels, but don’t be fooled, not all grabby pads are high wear, and not all lower friction pads are long life. The last thing to keep in mind is noise. There are some shims and tricks that can be used to provide a good reduction in the squeal, but usually the higher performance pads the louder they get. With a more metallic than composite formula, grinding/dragging sounds occur, while most any pad out of its ideal temperature range will result in squealing. I’ll give some suggested compounds and products but also refer to the interactive graph below supplied by Ferodo to help clarify what friction versus temperature looks like. µ is the unit of measurement of friction called Mu. Sound familiar? Another brand that is popular is Project Mu.
As you’ll see, the DS2500 can brake nicely and evenly across all temps you’ll see on the street while not beating up your rotors or your wallet. Some similar suggestions for street driving are Girodisc Magic Pads, Project Mu B-Force/Spec, Ferodo DS2500, and Hawk HPS pads.
Competition pads are a whole new territory! No longer do you think about wear, noise, or colder feel/performance. You are strictly looking for the pad that can survive abuse via heat, pressure, and grab. These tend to have severe noise especially when cold, but often they are noisy at all temps. The graph above can showcase the Ferodo DS3000 and DS1.11 as a good contrast though on the surface they may not seem like it. The DS3000 has better power at higher temps, but down low, aren’t ideal for quick brake stabs. How does this translate to the real world for your competitive events? Well, the DS3000 won’t be great bite right out of the autocross box comparative to the DS1.11, while on a mid-size road course the DS3000 might have better friction under heat. The DS1.11 is more consistent, thus more predictable. If the brake pads were rated for temps higher than 700*C, the DS1.11 might out brake the DS3000 if needed. There are going to be thresholds to take a look at. Most brake manufacturers rate the competitive brakes with two features: peak Mu and highest temperature they hold up to before degradation of the pad itself. It is important to get a feel for how hot your brakes get, and frankly, 700*C is easier to get to than you might expect. Driving habits matter!! When it comes to friction, the same side effects of rotor wear, noise, and Mu curve tend to apply, much like street pads. Some picks of mine for a range of competitive driving would start with Project Mu Racing-series, Hawk DTC series (50/60), and Ferodo DS series.
In conclusion, I would rather ignore “I daily my car but need a pad that can do it all!” This isn’t a great idea for a few reasons. You’re going to either wind up with an expensive pad that tears rotors and itself apart or more dangerously, you’ll get a pad that is livable on the street, but dangerous on track due to the fact it still may fade and fade HARD. Of course, with any modification in pads, I suggest high-temperature brake fluid as well. As for picking pads for your application, this article above should be helpful. For multiple purposes, I do suggest owning more than one set of pads.