daven1986

Slamming on the brakes hard and coming to a stop quickly

OR

Slowly putting on the brakes and coming to a stop over a greater distance?

To me it seems that in the first case you are using the brakes for less time but the friction on the pad is much greater thus wearing the pad more quickly. In the second case you are using the brakes for longer but the friction is much less so the pads get worn more slowly.

So basically they wear the pads the same amount.

Is this correct, or is one way better?

Daven

AEO

good question.
I think it's the same.

Only exception might be when there is prolonged use of brakes, and you want them to cool down.

jimc101

Would add to that the conditions you are in, if dry, pads should last a long time, unless dragging, in the wet, wear can dramatically increase as you are getting more contaminats on the pads; and if off road, on an MTB, the type of surface can alter this, sandy, rocky or mud, can increase or decrease pad wear.

Add on top of that if using disc, if the pads were not bedded in correctly at first, this can increase wear to bedded in pads

fietsbob

Road Grit and Mud.

furballi

Light braking will extend the life of the pads and rims. There will always be some contaminants like dirt on the braking surfaces. Hard braking puts these stuffs to good use.

HillRider

From a theoretical standpoint the amount of momentum and energy to be absorbed is the same either way and only the power level (work per unit time) varies. Hard braking will generate higher rim and pad temperatures as the energy is dissipated as heat over a shorter time so less cooling occurs. In normal use this effect should be minimal.

As AEO mentioned, temperature becomes an issue only in prolonged braking such as mountian decents.

As to abrasion, I expect it's the same either way too. Light sanding for a long time wears away things just as much as heavy sanding for a shorter time.

well biked

I do understand that this is kind of an intriguing question, but I don't think you should take it too seriously. What I mean is that, when you're riding your bike, use the brakes however you need to for what the circumstances call for. For example, if you're bombing down a hill at 45mph and approaching an intersection, don't be thinking about preserving your brake pads, just do what you have to do.

FBinNY 

+1, use the brakes as needed, and not when not needed without worrying about something that you have little choice about.

The only time you have a decision about how to brake is when doing long descents. Here, I follow the what automotive experts suggest which is pulsed braking at intervals rather than continuous braking. It sort of makes sense since the shoe is usually of an insulating material vs the rim or rotor which absorbs heat quickly, so most of the heat energy from braking will go the rim or rotor.

With continuous braking you have lots of time with the shoe in contact with the hot rim/rotor allowing the pad to heat up and soften (brake fade). In pulsed braking the time intervals are shorter keeping the shoe cooler.

operator

Uh what?

Brake holders are usually a metal that conducts heat very well. Heat dissipation off carbon rims for example, relies on using the holders/brake calipers as a heatsink to prevent high temperatures from ****ing the rim up on long descents.

FBinNY 

What I said applies mainly to metal rims or rotors, which rapidly take up the heat generated on the surface. With or without metal holders the brake shoe (pad) material is a poor conductor of heat and so takes up little of the heat generated at the surface.

Anyone who's curious and wants to confirm is invited to conduct this simple experiment. Find a short steep hill, descend until you've achieved a decent amount of speed and apply your brakes to a hard and controlled stop, so as to create a decent amount of heat. Dismount and touch both your brake shoes and rim. You can decide for yourself which is cooler.

Carbon rims are more complex because while carbon fiber itself is a decent heat conductor, the structural matrix is less so. Carbon makes a less than ideal braking surface because heat generated at the surface isn't conducted away effectively in either direction, (to shoe or rotor) causing higher surface temperatures than would happen with a metal rim.

On any well engineered brake system, the rotor is the better heat sink, offering both higher mass as a sink, and more surface area for both heat absorption and dissipation to the surrounding air.

BCRider

The energy to be converted to heat by the brakes is the same for any given speed and mass regardless of the speed of the stopping.

Something to consider is that the rubber/plastic pads used for rim brakes is almost always a poor conductor of heat compared to the aluminium rim or the aluminium pad holder. As such heat generated at the contact face of the pad is going to flow slowly through to the holder. And in fact most of the heat from the contact friction will be carried away by contact with the rim itself. Only later after the heat has had time to pass through the thickness of the rubber will the holder itself finally get warm. So a hard short stop will see the temperatures of the face and first thin layer of the pad soar higher from hard use over a short time where it has less time in contact with the rim to sink the heat away than it would over the course of a long gentle stop.

But I also agree that this is the LAST thing you should be thinking about while riding. The only time it would in any way have any bearing on how to ride is on a long descent. Then the question becomes do you just ride the brakes all the way down or is it better to slow down then let the brakes go and speed up and then brake hard to slow down again. In that case there's another factor at work. If you let yourself build up some speed and sit up tall in the saddle you'll generate more wind resistance at a higher speed. That resistance aids the brakes by shunting away some of the energy to aerodynamic drag braking vs converting the entire height of the hill into heat in your brake pads.

downtube42

I was wondering this yesterday, when the last 60k of my 400k brevet was in the dark on twisty hilly roads. I mostly rode the brakes on blind downhills, but I was curious if that was wearing out the pads faster than pulse braking would. Good to know there's little difference.

Woodwind314

Braking slowly over a longer distance will produce a little less wear for 2 reasons:

1. when the braking process takes longer, more kinetic energy is dissipated by the wind and (to a small extent) the rolling resistance of the bike

2. The heating of the brake pads softens them, resulting in more (easier) abrasion

What really helps reducing brake wear is to just lightly tap the brakes a few times before applying real pressure, as this gets rid of a lot of the grit that has accumulated on the rim or pads. This is especially useful when riding in the wet. The difference is easily heard!

PS: Going downhill 'pulse braking' might be better - if your top speed between brake 'pulses' increases over the speed you would attain with continuous braking. The faster you go, the less you need to brake!

daven1986

Woodwind: your point 2, surely that would be increased by braking over a longer distance. With quick braking you are heating the pads a bit but there isn't much time to wear them while heated.

I have been experimenting with tapping the brake a few times when coming up to lights then coasting to a stop. Works quite well.

Woodwind314

That was what I was trying to say. Sorry if I was unclear.

The real point is not direct pad heating, but rim heating. As long as the rim is still cool, it is the main dissipator of heat also for the pads during braking. The rims are cooled by the wind. So, while braking hard for a relatively short time, a lot of heat is generated, but is whisked away very efficiently by the (still) cool rims, which are subjected to a lot of wind (from going fast) at the same time.

Slow continuous braking will heat the rim, which gets little air cooling due to low speed. So the temperature at the pad-rim junction rises, weakening the pad. More wear results.