Stock pads dangerous in cold/wet @ highway speeds?

[SloS14]

It's been cold and wet for 2 days straight and for 2 days straight I've had incidents where I had to brake at highway speed and it felt like my brakes weren't there. Took a good half-second to boil away the water. Scared the crap out of me.

[sshole]

This will happen on any car that has modern braking system (aka caliper and rotor).

[Apoc]

Originally Posted by SloS14

It's been cold and wet for 2 days straight and for 2 days straight I've had incidents where I had to brake at highway speed and it felt like my brakes weren't there. Took a good half-second to boil away the water. Scared the crap out of me.

Your ABS will be making it feel like your brakes aren't working but they are actually preventing you from losing traction completely when you panic brake.

[ZionsWrath]

Yes I noticed this too, first car I have noticed it on but that doesn't mean it doesn't happen on other vehicles. Maybe since it is lighter and takes a fraction of a second longer to get the water off.



Easy solution, drive hard and keep the brakes above 100C

[PMPB]

Buy slotted rotors?

[Mikem53]

Originally Posted by Apoc

Your ABS will be making it feel like your brakes aren't working but they are actually preventing you from losing traction completely when you panic brake.

You know when the ABS kicks in.. You can hear the system modulating the brakes.. I experienced the same feeling the other day in the cold rain..
Takes a fraction of a second before the brakes dry, heat up and grab..
It's not an ABS thing.. It's a non linear feeling when braking that you normally don't get in warm & dry conditions.

[DM7]

Like others have said water on the surface of the rotors and pads of any brake system will cause this to happen. Now that you have experienced this you will be prepared for it to happen again and take the necessary precautions/anticipate the initial reduced brake feel.

I have experienced this when using the brakes in this and other cars when it has been sitting in the rain or right after a car wash at low speeds.

There is a racing technique that drivers will use on cars with floating calipers that could be applied here. The pistons in floating calipers can get knocked back into the bore increasing the distance they need to travel before the pads contact the rotors. Racing drivers will tap the brake pedal before they enter a braking zone to reset the pads and pistons to take up the slack in the system. When they actually start braking they have normal brake feel immediately. You could probably use this technique to quickly wipe the water off the rotors and pads before you need to use the brakes. In all honesty for public road driving/commuting at normal speeds it's overkill. It's better to just be aware that it may happen and use caution.

[wheelhaus]

Brakes work by converting kinetic energy into thermal energy via friction, so anything that prevents that will reduce their effectiveness. Even a very fine film of water will act as a a lubricant until it's dissipated.

Similar to what DM7 said, I've found tapping the brakes or lightly dragging them for 1-2 seconds occasionally while driving on very cold/rainy days will help improve the initial bite. BMW even had a system that would detect rain and would very lightly apply the brakes (not enough to upset the car) to keep water off the friction surfaces. This was a few years ago, not sure if it's still in use.

[SloS14]

I've probably got a good 300k under my belt in 25 different cars. Haven't experienced this problem with this severity (that I can recall) with factory pads. It's not ABS.

I'll just have to be mindful of keeping them warm like DM7 suggested.

[OrbitalEllipses]

Originally Posted by DM7

There is a racing technique that drivers will use on cars with floating calipers that could be applied here. The pistons in floating calipers can get knocked back into the bore increasing the distance they need to travel before the pads contact the rotors. Racing drivers will tap the brake pedal before they enter a braking zone to reset the pads and pistons to take up the slack in the system. When they actually start braking they have normal brake feel immediately. You could probably use this technique to quickly wipe the water off the rotors and pads before you need to use the brakes. In all honesty for public road driving/commuting at normal speeds it's overkill. It's better to just be aware that it may happen and use caution.

Anti-knockback springs and a stronger hub will prevent this - though those aren't going to options for 95% of people.

[Porsche]

In conditions where my brakes may be wet and the rotors coated with a light rust "glaze," I will exit my driveway and immediately drag my brakes with my left foot, with additional throttle. I'll drag them like this for, maybe, 50 yards or so. Then I'll test them.

This cleans off my brakes, after which they work fine. If I forget to do this, I can sometimes get an unhappy surprise should I need to suddenly brake hard.

You might try this technique and see if it solves your problem, too.

[immortal_suby]

I've noticed this delay in the rain on my BRZ also. Never noticed it on any other car. It's not the ABS.
I get no delay in my svx, but it has slotted rotors. No delay in the wife's outback on stock brakes.

[regal]

Its not the brakes look at the tires These are summer tires, the tread becomes stiff below 32F, do not drive with them in the winter. Completely not safe and engineered that way for good summer performance/economy. Buy some all seasons if you don't get much snow, if you do get snow buy a set of 16" wheels (old wrx alloys are nice) and put a set of 205/60/16 snow tires on it before you spin out and wreck. The 60 A/R raises the car and fills in the wheel gap. That extra inch of height makes a huge difference in heavy snow.

[Black Tire]

I haven't had a problem with mine. In fact, they really seem to grab well in all conditions. Some possible solutions:

• If the pads are very worn, they have longer to travel before hitting the rotor. Time for new pads?

• Change to a good DOT4 brake fluid, flush and bleed the brakes.

• Install a master cylinder brace from Grimmspeed or Perrin.

• Upgrade to stainless steel lines.

• Hammer the brakes really hard for several near-stops in a row from 50-60 mph in dry conditions. Sometimes gently driven performance brake pads develop a slight glazing on them that reduces their effectiveness and heat cycling them will bring them back to life. [Or just attend a track event and this will take care of itself.]

My car has all of the above upgrades/uses, so it may just be that I have forgotten some of the feel of the stock brakes.