Charlie Ky

My Specialized Roll has about 200 miles on it now. Mostly level pavement riding. In general, how many miles should the pads last ?

msalvetti

I was wondering the same tonight, but I quickly figured out the answer - it depends.

So far I have about 1,000 miles on my Shimano hydraulic disk brake pads that came on my Trek. I only ride a MUP, about 18 miles each ride. But it is heavily urban, so those 18 miles probably have 40 or 50 road crossings, many of which are blind and require me to slow down quite a bit (from about 15 mph). I'm 250 lbs so they have to work.

I just measured my pad thickness, and they are about 2mm. According to Shimano, they started out at 2mm, and they need to be replaced when they get to 0.5mm. I'm sure they are worn at least a little (I didn't pull them to measure), so at this pace I think I'm going to get at least 3,000 miles, and I think I brake a lot.

Mark

cxwrench

You can burn through a set of pads in less than an hour or they can last a year or more. Totally depends on conditions. It's like asking 'how long is a piece of string'?

Charlie Ky

Ok thanks, I have calipers so I'll use the .5mm mark as a guideline.

well biked

Yep, just too many vairiables. Let's round it off to 50 miles to 5000 miles. With an emphasis on "round it off." I once did a very nasty mtb endurance race (52 miles), in horribly wet and abrasive conditions, that required replacement of every wear-and-tear part on the bike afterwards. Including the brake pads, which were replaced just before the race. I also have a couple of road bikes that are pretty speical to me, and only get ridden in dry conditions, and I might never have to replace the brake pads again, even after many thousands of miles. Hope this illustrates my point.

Bottom line: replace the pads when they need to be replaced; there's no mileage standard.

HelpSingularity 

If you are like most people and don't usually ride in the rain and you're not regularly riding down long, steep, and twisty mountain sides with 50 lbs on your bike along with your 250 lb carcass then my experience is that half way decent brake pads, like Kool Stops, last a really, really long time.

jccaclimber

Not very long if you drag the brakes them down hills or ride a lot in wet dirty conditions. Seemingly forever in clean, dry, level conditions.
On one of my bikes I go through a set of tires every year or two. I go through a chain every few years. When I lived in flat areas I don’t ever remember having to change my brake pads on that bike.
Now that I live in an area with a lot of steep hills with stop signs at the bottom it looks like I’ll be replacing my pads with every other tire change.
How often you might want to give them a small adjustment is perhaps a more important question, and depends on the specific model of brake caliper.

yannisg

Totally agree.
I went through a new pair of quality rim brake pads in an 8 hour brevet in raining conditions. The grit from the road completely chewed them up.

JohnDThompson 

Brake pads only wear when you're using the brakes, so there's little or no correlation between miles ridden and pad wear. If your riding includes lots of long downhills your pads will wear faster than if you ride moderate speeds on flat roads. Just look at the pads to assess wear. If you're not sure what constitutes a worn pad, have your LBS take a look. They can probably show you examples of worn pads you can compare to new pads and the pads on your bike.

Charlie Ky

Thanks, the shop told me I can bring the bike back in within a year of purchase and they'll do a free tune-up and all. I'm not sure that includes all parts needed but that's no big deal.

I'll go ahead and run by there today and pick up a new set of pads to have ready when the time comes. I haven't ridden on wet pavement yet and the pads aren't squeaking or anything. Plus I've just been using the rear brake ~ 90% of the time. I've only had to apply the front and back brakes hard once when I noticed I was getting ready to roll over some glass.

HillRider

That's a mistake. Your front brake is capable of well over half of your braking effort and should be used in conjunction with your rear brake. Don't be afraid of it and get used to using it.

Iride01 

You shouldn't need to replace brake pads on a bike that's only gone 200 miles. So don't be in a hurry to replace the pads. Just let your bike shop do a inspection and adjustment of the whole bike and go with what they tell you.

If your brakes have been feeling like they aren't stopping you as well, it's more likely that they just need to be adjusted. Be sure to mention that to the shop and any other thing that seems to be not quite right.

Brake pads should last you quite a few years unless you put in serious mileage in harsh conditions. On the level riding terrain you say you are on, you might never need to replace the brakes.

Yan 

Half? More like 100%. Rear brake is completely useless. I use my rear brake less than ten times in a year.

This applies only to pavement riding. Off road you do need rear brakes.

Rick

Rim brake pads last longer.

cyccommute 

Even if you do regularly ride down long, steep, twisty mountains with that much weight, you brakes can still last a really, really long time…even if you do it off-road. I go years without changing pads.

ClydeClydeson

Shimano used to (still do?) sell 'M-Condition' brake pads for cantilever brakes that were (I think) an 'extra soft' compound. They worked great, but if used in muddy conditions, could be worn out in a single ride. Normal pads, in more forgiving conditions, can last several years.

cyccommute 

No, front brakes don’t provide “more like 100%” of braking. There are times where the front brake provides 100% of the stopping power but that is usually at the point of disaster. The rear brake provides up to about 20% when seated in a “normal” position but that decreases as the weight is shifted forward until such time as the rear wheel is lifted. Shifting the center of gravity rearward and down, i.e. pushing back off the saddle and down, greatly increases the deceleration and the influence of the rear brake.

Not using the rear brake throws out about 20% of your deceleration ability in the initial part of the braking curve. Using both…at least in the early stages of braking…greatly increases your braking ability.

cyccommute 

Sorry, no. Disc pads and rim pads have similar longevity. Disc pads are thinner but made of a tougher material but they are also being used on a harder material. Rubber pads are softer and thicker but they can scrub off faster. Neither really has an advantage.

cxwrench

As others have posted the rear brake is not what slows you down. The front brake is much more effective. Look at any car or motorcycle and pay attention to the difference in front and rear brakes. As soon as you start to decelerate weight is transferred to the front wheel(s). The harder you decelerate the greater the weight transfer.

Yan 

There's no such thing as a braking curve. When you are about to be run over by a car, you go from zero to full brake application at the human reaction speed. At this point, if you have applied the correct amount of front brake to come to an emergency stop with the rear wheel barely lifting off the ground, whether the rear brake is simultaneously applied has zero effect on the physics of the bicycle. Furthermore, if you are having to emergency brake during a turn, applying the rear brake will turn a bad situation even worse. When the rear wheel skids you will instantly crash.

If you are talking about a non-emergency situation where one has time to gradually ramp up the brake force, then this whole conversation is irrelevant. You can use whatever brake you want. It doesn't matter.

Charlie Ky

Well my rear brake stops me just fine. My route includes a lot of intersections and I'm usually going ~ 8-9 miles an hour or less as I approach them. The only time I had to stop quickly was when I saw glass I was about to run over so of course I used both brakes.

I spent my first ride on my new bike getting familiar with disc brakes both downhill and on level pavement. And when I do stop I grab the front brake lever in case the rear brake fails.

I have a phone bag mounted on the bike and the first few rides I just put in a random destination on Google maps and enabled the speed limit indicator to get a feel of how fast my average speed was. I seldom hit the 15mph mark. My route is access roads along a parkway and side street in a nice neighborhood with a lot of old houses. I just ride for enjoyment instead of endurance training and still burn some calories while I'm at it.

If I rode a road bike in a group using both brakes would be a given I'm sure. I just figured using the rear brake most of the time would require replacing one set of pads at a time instead of both wheels. Silly perhaps but hey, noobs gonna noob lol.

Rolla

I promise you it does not.

dsbrantjr

I'd suggest you get used to using your front brake preferentially, so that it is a reflex when the time comes where you need to brake really hard in an emergency.

cyccommute 

Of course there is a braking curve. The deceleration is not instantaneous and occurs over time and distance. That’s going to result in a curve.

It takes a finite amount of time for the center of gravity to move forward so the weight shift isn’t instantaneous, either. Until the rear wheel lifts, the rear wheel is contributing to the overall deceleration. Throwing away 20% of your braking power isn’t effective braking. Yes, once the rear wheel lifts, it isn’t contributing any deceleration but it takes time to get to that point.


No. You go from zero brake application to starting to apply the brakes at the human reaction speed. It take further time for the brakes to decelerate the bike. There is a stopping distance that is only loosely related to the amount of time it takes to apply the brakes. It can even be calculated based on the rider/bicycle weight and speed.

In an emergency stop, there is seldom time to do the calculation of “the correct amount of front brake”…there are other things on the rider’s mind. If you don’t use the rear brake, you are also missing an important feedback on whether or not you have lifted the rear wheel. Mountain bikers…who tend to know a whole lot more about brakes, braking, and how to use them…use both brakes and then get off the front brake when the rear tire starts to skid. A skidding wheel has almost no control and a bike in a nose wheelie is essentially a very bad unicycle.

Only if you don’t know what you are doing. Going back to mountain bikers (and any 10 year kid), a sliding wheel in a turn doesn’t result in an “instant crash”. It may result in a crash but it’s not instant nor inevitable. It’s not difficult to use your hips to keep the bike from sliding out from under you. Getting off the brakes also goes a long way to stopping a skid.

Your initial post didn’t say anything about emergency nor non-emergency situations. That said, good braking techniques during regular braking…i.e. using both brakes, knowing what to do when the rear tire skids, understanding braking dynamics, etc…are the same as those need in an emergency.

Yan 

I can get behind most of what you are saying. There's no problem with always applying both brakes, because I agree there are no major downsides so "why not".

But there is no significant curve as you call it. The braking force is the friction force between the rim and the pad. The friction force is the normal force times the coefficient of friction. The coefficient of friction is a constant. The normal force is your finger force. Your maximum finger force is a constant because it is limited by the flip over point of the bike, which is a function of the earth's gravity which is a constant. You can argue it takes some fraction of a second for your finger muscles to achieve full grip strength. But whether you are squeezing one or two levers has no effect on this delay.
Once the braking force is applied, there is no delay until weight is transfered to the front wheel. The force is propagating through the atoms in your frame at nearly the speed of light. There is a slight delay in the weight transfer due to the spring of your musculature and the front tire. These delays are negligible. You're certainly not going to be able to claw out any additional rear brake contribution within these millisecond timeframes.

But I agree the rear brake does give feedback. Furthermore if someone is unsure where the flipping over point is, they will be inclined to gradually increase their finger force to test the waters. In such case there is indeed a curve and there will be an advantage to applying the rear brake. However I think this is an argument for rider training, not rear brake use.

Finally I think there is a danger that someone squeezing both brakes may not squeeze the front brake as hard as they otherwise would, which will increase their stopping distance. End of the day the front brake is what actually stops you. If your one hand is stealing strength from the other hand you're just sabotaging yourself.