voyager1

Campag4life

Uh oh. Should be a duesy.

voyager1

Elvo

It depends. If it's just clean dry road riding your rotors might last 20k+ miles and your pads 10k+ miles. If it's wet, muddy, and slushy you might get 1k miles.

voyager1

Campag4life

No you are totally cool and a fair newbie question. Disc versus rim is a pretty divisive subject on bike forums as camps are divided. But will give you my pretty succinct take.

I just bought a new Di2 race bike with rim brakes. I very deliberately chose rim brakes. I don't like disc brakes and have owned them on different bikes.

I am not adverse to tech, hence Di2 and the latest bike tech but where I draw the line at brakes is...
-If I live in the mountains or pronounced hills with high speed descents, I want disc brakes.

-If I live more normal terrain with rollers, bridges, some climbing but not predominant climbing, I want rim brakes....like where I live now.

So to me, this should be the discriminator. Why not discs for every situation? They cost more, are slightly heavier...not much...but moveover, they require more specific maintenance. Get ready for the onslaught that says disc brakes are easy to maintain. Tell that to those that can't get them to stop howling or rubbing.

Now...as to mechanical versus hydraulic? To me there is NO comparison. In spite of what may seem like more complexity with hydraulic fluid which is true, get hydraulic discs EVERY time. There is no comparison. Modulation and even adjustment is easier with hydraulic. Hydraullic is the only way to fly.

Every serious road cyclist has an opinion on this subject. I love rim brakes. The new dual pivot Shimano rim brakes are simply outstanding. Others only want disc brakes on their new road bikes. Camps are divided. You probably have to own one or two bikes with disc brakes to decide if you prefer them.

Good luck

noodle soup

Unless you are a total penny-pincher, the difference is negligible.

if you are buying SRAM/Avid brakes, you might want to learn how to bleed brakes

it’s not hard to do, just something different.

jpescatore

I'm two years in on my first disc brake bike, so far the only difference in cost was that a set of pads for disc cost about $5 more than a set of rim brake pads. From a reliability point of view, so far identical to rim brakes. From a stopping point of view, superior - and disc brakes enabled me to use wider tires (32mm) on the new road bike.

The bike shop I says shouldn't have to replace brake fluid before 5 years unless something starts to leak before then. Rotors will need to be replaced at some point in the future, too.

Yes, disc brakes will definitely cost me more in the long run but I could also choose my tires by lowest cost of ownership vs. performance in the rain or under load going downhill, too - but I don't anymore. If the only criteria is cost, rim brakes definitely win.

Ald1 

Great post on the subject. I'll add Disc allow less rim wear and more tire width options. I live in the mountains and enjoy one mile plus decents and have HDR sram discs and love them.

Campag4life

Thanks. I try to distill the debate down because both sides are so entrenched in their view. To me, which type of brakes completely depends on where you live and ride.
A further analogy. Lets say you own a hotrodded Toyota Camry that you enjoy driving on the street. If you never track the car, then you likely won't need big Brembo brakes to bring it down to improve lap times.

Same with bikes. I never think about my brakes. Ever. Only in terms of adjustment in terms of lever pull each side. Its because I don't brake much...hardly ever because I live in flatish country. Only few descents I do, I only touch the brakes and rim brakes work fine.

But...if I lived where you do, I would be with you on the best hydraulic disk brakes you can get. I totally get the long descents where you are on the brakes a lot of the way. Most of us don't ride in the mountains like pro's and let our bikes reach 60 mph on descents. We must worry about cars and ride in an open and not closed environment.

Shameless plug for my new bike below. A bit different now with longer stem and different wheelset. But brakes aren't even a consideration. Shimano dual pivot brakes are fantastic. I wanted the lightest and most aero setup which in the context of brakes also happens to be less expensive which is why I chose this bike config...but in the mountains, I would be on disc brakes.

Jakedatc

For hydro brakes considering the housing or fluid doesn't have to be replaced very often it is less there (vs housing and cables) Pads and rotors last a long time as long as you take care of them and don't wack your rotor into a curb or something. bleeding is not too difficult and you can get fluid fairly cheap that will last a long time (make sure you get the correct kind and bleed kit for the brakes you have) watch youtube videos on bleeding your type of brake

MoAlpha

Others may quibble with my numbers, but I have been able to find non-finned. resin, OEM Shimano pads for my RS505s for under 10 bucks. The other consumable is hydro fluid, which is, like, what? Twenty bucks a liter? So, very generously, ~ 42 bucks a year for two sets of pads and a flush. Rim pad inserts are 8 or 10 bucks a pair and figure in a cable or two every now and then, so double or a little more, i.e. 20 bucks a year difference, and this is real worst case for a road bike. Then, of course, one must consider the eventual cost of replacing a rim vs. a disc, which could pay for several years right there. If you're budgeting at that level of detail, good for you.

WhyFi

You're asking about maintenance costs, so let's look at the math.

1L of Shimano mineral oil (unlike SRAM, they don't use brake fluid) is less than 20 bucks. When I installed my brakes, I used ~50mL, so the bottle will get you 20 flushes at $1 per. That was for the gravel/foul weather bike and it was a year and a half ago. With ~6k miles on that fluid, it still doesn't need to be flushed. If you want to buy the little 50mL bottle for convenience, they're ~$10 a pop.

I use the more expensive sets of Shimano pads (resin pads with fins) and they're about ~$18 per wheel. I've replaced one pad set in that time (FWIW, replacing pads takes less than 10 minutes and requires a screwdriver and a tire lever [to push the pistons back in]).

If you want to look at rotor costs, we can, but then we'd be comparing $30-50 rotor to rims/wheelsets and the disc option is going to come out on top, 'specially with carbon wheelsets.

WhyFi

Damn @MoAlpha ninja'd me with all the same points.

MoAlpha

Great minds, my friend.

Bob Ross

Humor me: How do you adjust hydraulic disc brakes?
Or, more specifically, which parameters are adjustable?

Campag4life

I think many here are making a good case that maintainence costs of hydraulic brakes should not be a detriment to choosing hydraulic disc brakes. I agree with that even though I am not a general proponent of disc brakes for most riders. So what matters then? Weight a bit different, aerodynamics...both btw aren't much...but maintenance aka time and not cost so much is a consideration. Most believe...my opinion is...disc brakes are more fiddly than rim brakes. Some may disagree but my opinion including owning hydraulic disc brakes on motorcycles.

But to get back to my personal position? None of it should be overriding. The overriding determinant isn't slightly more maintenance versus not, slightly higher cost versus not, very slight weight penalty or aero performance versus not...none of this is enough to move the needle. What matters? Braking power should be commensurate with elevation changes one rides. Elevation difference equals more potential energy which can be handled better with disc brakes. Hydraulic disc brakes are more powerful. If you need this power, get them. Don't change elevation much like in my case? Save the hassle and stick with rim brakes. To me disc brakes are worth it when elevation changes are extreme but not when riding more ordinary terrain.

I tend to agree with this reviewer...but to me the conversation is more nuanced. More powerful brakes makes sense in more extreme riding conditions.

base2 

All things being equal, disc performance is equal to to negligably better than rim for most dry situations. In the wet, disc is better, hands down. One caveat is what mix of components you have. I've had a real garbage disc/caliper combination once and it put me on the wrong path for a long time. Eventually I had one too many close calls and got a case of upgradeitis. Right now I have TRP Spyre SLC's or Avid BB7's and 180mm rotors on all my disc equipped bikes. I weigh 200, & ride near steep hills, in traffic and this combination is more than adequate my my needs.

In terms of cost: Disc brake pads are cheap. Rotors are expensive. Rim brake pads are nearly cheap, rims & wheel build are expensive. My gut feeling says disc if cheaper if you extend the ownership timeline long enough. I have several worn rim brake rims hanging in the garage. A few winters is all they ever managed.

raria

Well said and I'll add that for dry conditions mechanical disc brakes are overkill. Good cantilever V caliper brakes are perfectly fine in those conditions if you have quality pads

Campag4life

Will give you a tip based upon personal experience. If you have a disc bike and want to treat yourself, toss the BB7's and put some good quality hydro disc brakes on your bike. Night and day compared to BB7's which I too have owned in the early days. If running disc...my personal opinion is, hydro is the only way to fly. BB7's are way more finicky for set up and don't have nearly the power hydros have.

base2 

I am inclined to agree with you. However, the BB7/180mm bike has 26 inch wheels. Combined with the OEM cantilever brake levers it is almost too much. My kid & I switched bikes on a ride & he endo'ed the first time he hit the brakes. They do work as much as I feel comfortable. FWIW They are on a 1997 Trek 6500zx with Rockshox Recon forks.

I have a serious mind to go to 160mm rotors, but probably won't bother unless I actually start getting serious off-road miles.

Psimet2001 

I see lots of good people have chimed in on here with lots of good info. I wanted to respond strictly from the position of a mechanic, shop owner, and team mechanic and race mechanic.

If you have rim brakes and come to me and have me redo the whole system (per caliper):
Cable inner: $5
Cable Housing and ferrules: $5
Pads (alloy Shimano): $10
Brake adjustment: $5-$10.

I would consider that to be annual maintenance on a cable rim brake system.

Hydraulic disc Per wheel:
Pads: $17-$30
Brake Bleed: $30-$35

Possible new rotor? $40-$80
Caliper issues (SRAM stuck piston, sticky master cylinder, etc): +$40


From my position are disc brakes "better" for road. No. not yet.
Do I like them? Yes.
Are they safer? kind of. Yes on nice systems that are well maintained for enthusiasts or racers... No on big box store bikes that are never assembled correctly and used by the common person once or twice a year. The odds of them working correctly are greatly lower than similar level cable and rim brake systems.

Its the same with tubeless technology. Fine for enthusiasts but definitely never going to work for the masses.

Psimet2001 

I loved BB7's for years and still have them on my son's cross bike. Like Shorty Ultimates are for cantilevers - BB7 are for mechanical discs. That being said they all suck compared to hydraulic.

Campag4life

I thought those interested in this discussion would appreciate comments from both a 20 yr. ex pro and Warren from Bikeradar.
What I believe to be particularly enlightening...is perspective from a guy in the trenches who uses the tech in a workman like manner...and btw the pro loves Shimano Di2...versus a self professed bike 'geek' Warren who really drills down on the minutia of tech. They come from different worlds of course and two guys who know a lot about bikes end up with divergent views. I am certain Warren is a champion of disc brakes.

This is a broader discussion about what matters in bike tech but begins conversation relative to brakes. Some compelling comments.
The pro said something quite interesting. He believes the choice comes down to 'skidding the tire'. Of course proponents of discs will quickly rebut this and say that the superior modulation of disc brakes prevents skidding the tire more than rim brakes, but perhaps not in the eyes of a skilled rider who can modulate weaker rim brakes just fine.
Bike of the year was discussed which is the incredible value of TCR Advanced 2 which happened to be a rim brake bike. as well.

Enjoy the conversation. PS: if you want a laugh...read the comments under the video throwing the ex pro under the bus.
Worlds divided. Part of what separate pros from an 18 handicapper with an opinion...lol. A last note not often discussed. The reviewer in the first video touched upon it. He like myself never felt existing rim brake technology to be deficit. That was never his problem or mine. Rather, the bigger problem isn't slowing the bike down, but rather how to make the bike go faster. People have different priorities. No doubt a percentage that prefer disc brakes are more focused on slowing the bike than making it faster. I want to make the bike go faster and not slower like the reviewer. If looking for a further corollary, consider e-bikes. Some believe a 250w motor is all you need. Anything more would make the bike too fast and unsafe 'for them'. I would never buy an e-bike with a 250w motor. Bare minimum for me is 500w. I want a fast e-bike that will hit 28mph and sustain it...when the road opens up of course. Different schools.

Seattle Forrest

I've needed to have my brakes bled. I'm heavy but road standards, was doing a fast descent from a mountain pass, and got passed closely by a line of cars. Breezy day and I wanted to be slow and in control when they went by.

It costs about $40 per line, maybe less in other markets. The brakes still work when they need to be bled, but you have very little control over how much braking force, and the levers just feel bad.