Question: Are disc brakes worth it for road cycling or are they just extra weight? And if disc brakes are worth it, are hydraulic disc brakes better than mechanical ones?
RBR’S STAN PURDUM REPLIES: I never used disc brakes until I purchased my most recent bike about three years ago, which came with hydraulic discs. But in my 40 years of cycling before that, all on bikes with rim brakes (with one exception — I had a tandem that had a drum brake on the rear wheel, though the front wheel still had a rim brake), I never had a problem that made me wish I had some other means of stopping the bike. And even now that I’ve had experience with the hydraulic discs, I still wouldn’t be reluctant to ride with only rim brakes.
But having said all of that, my answer to your first question is yes, disc brakes are worth it for road cycling. I’ve had no opportunity to ride with mechanical disc brakes, but I can say that the hydraulic version provides an extra measure of smooth stopping power that I didn’t realize I was missing with rim brakes.
I first became aware of that extra measure when rolling down a very long steep hill to where it intersected with a crossroad, on which I wanted to turn left. The road I was on descended even more sharply right before the turn, and since roadside vegetation kept me from seeing whether there was traffic on the crossroad until I was right at the intersection, I had to come to a full stop with the bike still aimed nose down. I was able to do this without applying great force to the brake levers or locking the wheels; the bike just quietly stopped without skidding. And then, seeing at a glance that it was safe to make the turn, I was able to proceed without dismounting.
I believe I’d have managed all of that on a rim-brake equipped bike as well, as I have done on other occasions, but with the discs, I was aware of better modulation and less hand fatigue on the whole descent. And while I’ve said I have no reluctance to ride with rim brakes, if I were buying a new bike today, I’d get one with hydraulic discs — especially since I live and ride in a region with lots of steep hills.
If your question is preliminary to purchasing a new bike — as opposed to upgrading the brake system on your existing ride — your query may be academic. Although disc brakes were first introduced for mountain bikes, they have now become common on road bikes. In fact, it’s increasingly rare to find new road steeds with rim brakes, except from a few specialty manufacturers, such as Rivendell.
While I have no personal experience with mechanical disc brakes, I understand that they are less expensive, easier to maintain, and simpler to fix at the side of the road with basic tools. But I’m told that their braking performance and comfort of use is less than that of hydraulic systems.
Readers, can you weigh in regarding mechanical discs? Other comments are welcome as well, of course.
Stan Purdum has ridden several long-distance bike trips, including an across-America ride recounted in his book Roll Around Heaven All Day, and a trek on U.S. 62, from Niagara Falls, New York, to El Paso, Texas, the subject of his book Playing in Traffic. Stan, a freelance writer and editor, lives in Ohio. See more at www.StanPurdum.com.
Perhaps another reason for disk brakes lies not in the brakes themselves, but what they allow – such as unrestricted, unencumbered carbon rims (that don’t have to be designed to accommodate caliper brakes), and better frame clearance allowing wider tires and wheels.
This is a terrific point!
I second that point and the braking predictably in all conditions.
I recently bought a rim bike frame before they all went to disc brakes. Call me old school. I have hydraulic disc brakes on my mountain bike and they make sense there because of rims getting muddy and wet, but I don’t need them on my road bike. I run carbon rims and can easily skid if I apply the brakes hard, so now shortage of stopping power even with carbon rims.
I agree completely. I have hydraulic disc brakes on my MTBs, fat bike, and gravel bikes and consider them mandatory, given the nature of the riding and conditions I often encounter. My road bikes all have rim brakes and I don’t feel the need for anything else. I avoid riding the roads in wet weather, and although it’s hilly here in NH, I’ve never encountered a hill on a paved road required more braking power than rim brakes provide. If I lived out west where there are miles-long mountain passes where overheating one’s brake could be a concern, I might have a different view.
For the road riding I do, I simply don’t need disc brakes and I’d rather have lighter, easier to maintain road bikes.
My main complaint about rim brakes is that the braking surface — your wheels — is a wear item, and wheels are typically now in the thousand-dollar ballpark to replace. I’m not thrilled with having a thousand-dollar wear item.
That’s a significant point. Thanks!
Totally agree with you Steve. I have around 30k kms. on my HED wheels and they are close to being garbage due to brake wear. $$$$
Gee, I’ve been riding the same pair of aluminum rim wheels with rim brakes for the past 15 years, on my only road bike (S-Works Roubaix), probably averaging a bit over 5K year in the past, and somewhat less this past decade (I’m 76, now live in Maine, and use my rim brake Merlin mountain bike in winter). Am I due for new wheels – they look fine to me? Why would I want $$$ carbon wheels? So I can have a more “aero” wheel shape and save a minute on my daily loops? If I were to order a custom fabricated new bike – carbon or Ti with cantilevers so I could run tires wider than 28mm – probably 32-34mm.. I would not want carbon rims, with disc or rim brakes – preferring a rim that won’t shatter in the event of an unseen road hazard. So much industry pressure to make bicycles more and more expensive, without adding to the joy of riding. Mission creep without real justification.
In over 55 years of riding road bikes with alloy rims and caliper brakes, I’ve never had a rim that I had to replace due to brake wear. Not one.
Back before disc brakes became available, I recall having to replace ONE rim on a mountain bike because it wore thin and cracked. That rim saw a lot of riding in muddy/sandy/dusty conditions.
As for replacement cost, I build my own wheels, so it’s whatever the price of the replacement rim is, which is generally around $50. Even if you have a shop do the work, it’s typically under $150.
Are you actually going to replace an entire wheel just because the rim is worn? That’s crazy!
My quarrel ( retro grouch) is a decent bike can last as long as one is able to ride (80 y/o here). So why buy a new bike when the one one rides is serviceable? Rampant consumerism? Jus’ sayin’
I hear ya! I have several sets of perfectly good road wheels – and replacement rims are still available – so unless I trash a frame, I’m good for a long time. Even then, I’d look for a rim-brake frame, used if necessary.
I rode a Surly with rim brakes cross country about 10 years ago. There were a few hills in Kentucky that heated my rims so hot it burnt my fingers to touch them. I had to stop numerous times to let them cool down. In rain and hills I noticed a decrease in braking strength also. From what I’ve read disc brakes behave better in these circumstances.
They do, and if one rides in such conditions, disc brakes absolutely make sense. Around here, I only encounter similar issues on dirt/gravel roads, and I have disc-equipped bikes for them. For loaded touring, discs seem like the best way to go.
If one lives in an area with mostly flat riding and moderate hills, there is no need for disc brakes (in my view). Yes, I am old school. However, disc brakes do have merit on mountain bikes and road bikes if riding in hilly country with long, steep descents or when riding often on wet roads. In my experience with disc brakes, I prefer mechanical disc brakes for the reasons stated….and do not find hydraulic discs to provide an advantage worth the disadvantages.
Mechanical disk brakes are definitely less effective. I have them on a bike that has S&S couplers, so hydraulic was not an option. I got them when training for the Death Ride in California. I am not a very bold descender – was even less so then (10 years ago) so was quite disappointed. Now – it’s still a favorite bike – they feel fine, but not much different than rim brakes. I do have hydraulic on my e-bike, so I have experience with the difference.
Thanks for the comparison. It matches what I’ve read elsewhere about mechanical disc brakes.
I have a pair of Paul Klamper mechanical disc brakes on my touring bike, hydraulic brakes on my other two bikes, and find the Klampers to be almost indistinguishable from the hydros. They are not cheap, but very well built, and completely serviceable. The stopping power is amazing compared to other mechanicals I have ridden. These brakes are easy to setup and will pretty much last a lifetime.
There are couplers available for hydraulic disc brakes, but I don’t recall the name of the manufacturer.
Weather plays into decision. In rain or moisture disc are much more effective and efficient.
We went from a Rim brake (V Brakes) Tandem to Disk brakes on our new at the time tandem.They are mechanical but are a total game changer especially in the wet. We did a rough rainy descent in the Mediteranian Alps with friends on rim brake tandem. The difference was amazing as we got down safely and had to wait for the other team at the bottom. I still have a mix of rims and disk brake bikes. I ride them all and like them all….but in the rain I prefer disks.
Although there are some negatives with disc brakes, I am quite willing to live with those now. In my current locale, there is one ride that I like but has some hills that rim brakes are marginal for – at least for me. I have scared myself severely with rim brakes as I tried to slow for the hairpin curve at the bottom of one hill in particular (I am fairly large as well, so stopping me on a bike is a bit tougher). Disc brakes solved this issue.
Back when I still working for a living, I had some marginal carpal tunnel issues on one hand and that made shifting a braking both a bit difficult on that side.. When I purchased a gravel bike with disc brakes, I was shocked at how easy the affected hand could handle braking without issue.
A third advantage for disc brakes isn’t really related to the brakes at all, but most newer bikes allow wider tires. 25’s were the widest I could ever do in the past (exception; Bianchi Trofeo). The ability to run wider tires is quite nice for someone of my size, and even my very small wife has commented on the improved ride she is now experiencing with wider tires.
For most non-hilly road riding, even with carbon wheels, rim brakes have been fine. But when I’ve been riding the same bike in really hilly areas (5-15% hills that are long), I have found that I seriously don’t have enough stopping power, needing to squeeze as hard as I physically can and it was not enough and my hands fatigued very quickly. Hydraulic disc brakes makes the same exercise a fingertip operation. Of course for MTB, CX and heavy loaded bikepacking, it’s a no brainer. I’ve never used mechanical disc brakes, but I have 10,000 miles on my bikepacking/CX racing bike and have had zero reliability problems with Shimano GRX hydraulic brakes.
I always said that I didn’t need disc brakes on my road bike. I live/ride in mostly flat South Jersey and don’t ride in the rain. Then I bought a new bike with discs two years ago. I’ll never go back. The ease with which you can brake and the modulation/control are just far superior. When I ride my other bikes with rim brakes, it’s noticeably more effort to brake. It’s like most other innovations…we don’t always need them, but they make what we do easier and more enjoyable.
Sure, disc brakes are an improvement over most rim brakes. Having hydraulic, mechanical and mechanical/hydraulic hybrids I would skip the mechanical. The hydraulic calipers are far superior. Mechanical calipers often produce uneven braking force and uneven wear requiring much more frequent adjustment (think Avid BB5s). For my road bike with mechanical discs they are fine and easy to service. If I had stepped up to the model with hydraulic disc brakes I would have also gotten a better wheel set for a small price hit. I’ll leave the cantilever brakes out of the discussion.
I have a 2001 Litespeed with rim brakes( which I use for road riding thousands of miles around Phoenix) , a 2013 Seven touring bike with mechanical disc brakes (with which I do unsupported, loaded touring for weeks at a time) and a 2018 Pivot mountain bike with hydraulic disc brakes(with which I ride the fantastic mountain biking trails surrounding Phoenix).
A friend of mine was considering a new bike and asked me if he NEEDED to put disc brakes on his new bike. My response was to ask him several questions: 1. do you ride in the rain much?, 2. do you ride hilly terrain? and 3. will you be doing any loaded touring in remote areas with your new bike? His response to all three questions was NO. With his response my recommendation was that disc brakes are not absolutely necessary for the type of riding he does. That is not to say that he wouldn’t benefit from disc brakes. Having ridden with both mechanical and hydraulic disc brakes there are several characteristics to keep in mine when considering mechanical or hydraulic disc brakes.
Rim brakes are adequate for my urban road riding in a flat area that gets little rainfall.
Mechanical disc brakes are my choice for my loaded touring bike because: 1. I don’t have to worry about a brake fluid line breaking in a remote, hilly area, losing the hydraulic fluid and thus depriving me of my brakes, 2. cannot overheat my rim on a steep downhill and cause the tire to blowout (as I have heard happening to other touring cyclists using rim brakes on their loaded touring bike while riding cross country), 3. provide superior braking and smoother braking effort compared to rim brakes. .
Hydraulic disc brakes are great on my mountain bike because they do offer more powerful and smoother braking than either rim or mechanical disc brakes and mountain biking involves steep downhills on rocky surfaces. And since I am not riding in a remote area and can easily limp back to the trailhead I could live with the hydraulic line being cut, losing the hydraulic fluid and eliminating my brakes.
In conclusion, which type of brake you need on your particular bike is something only you can determine based upon how and where you are going to be riding. Of course as bicycle manufacturers move to eliminate rim brakes in the near future, it is likely you won’t be able to find a new bike with rim brakes and your only choices will be a version of disc brakes.
Thanks for the detailed and well illustrated info.
There’s really no realistic discussion comparing hydraulic disc brakes with rim brakes or even mechanical disc. They are far better modulating, and control is far superior and much safer. I’d say most people do not “NEED” hydraulic brakes as is true with most things we have. We could get along fine with a Yugo car. It’ll get to where you’re going but is sure is nice and a lot safer to ride in more expensive cars.
I honestly don’t think you comprehended my response. I’d like to see you riding your loaded touring bike with hydraulic disc brakes in the middle of some hilly, remote area in the US or Europe when your brake line gets cut and you lose the brake fluid and you have no brakes coming down a mountain pass. Maybe then you would understand. Driving your luxury car across the Sahara Desert wouldn’t get you very far. A camel would probably work better. Some applications outshine others in certain situations. Just saying.
Have you actually had a hydraulic brake line on a road bike get cut or fail? While I’ve heard of it happening on MTBs due to snagging something, I’ve never heard of that happening on a road bike of any type.
Have you ever done any loaded unsupported touring that puts you in a remote area? Sounds like your cycling never takes you a few miles from home. I guess it is hard for you to imagine a situation as I describe. What would you do in that situation (think no cell service to call Mom).
There’s one benefit for disc brakes that I haven’t seen mentioned. For riders with small hands, rim brakes can be problematic, as adjusting the levers close enough to the bars for easy reach can cause them to bottom out on the handlebar under hard braking. Consequently, they may be stuck with a compromise between easily being able to reach the levers and actually being able to stop. With discs, the lever throw required for braking is usually must less, which eliminates the issue with handlebar clearance.
I recently bought a used Tarmac SL8 with hydraulic disk brakes. The biggest downside is the need for a tool and more time to remove a wheel compared with the speed and simplicity of quick releases. The braking is amazingly smooth and effortless.
Other than that, I have a 2014 mountain bike with hydraulic disk brakes that I have not ridden for more than a year. I recently tried pulling the brake levers, because I couldn’t remember if they were hydraulic or cable operated. The rear brake still worked fine, but just sitting in the rack, rear wheel down, the front brake lever had no effect on the front caliper. It worked fine when I parked it, and there is no sign of any broken hydraulic line or spilled fluid. So apparently, it doesn’t take a loss of fluid for hydraulic brakes to become inoperable.
I have performed my first hydraulic brake bleed on the Tarmac, because I upgraded the levers and calipers, so needed to do the procedure. It went very smoothly and successfully. Probably that’s what is now required on the mountain bike. The key is to have the appropriate fluid (mineral for my MTB, and DOT 5.1 for the Tarmac). I’ll need to get a second bleed kit, because it is a no-no to contaminate one fluid with the other. But with the bleed kit, consisting of two syringes, one for the lever and one for the caliper, moving the fluid back and forth until no more bubbles appear at the lever end, the only downside I could see is the expense of buying the bleed kit, of which I will now need two.
It is really nice to know that the maintenance is so easy that I was able to get it right the first time and second times (both brakes done) with no mess. I’ve actually had more of a hassle with cable brake maintenance on occasion.
I also have a 1983 Gängl with Superbe calipers from the 70’s. I use Zipp brake pads designed for carbon rims on Zipp Firecrest 303 rims. I’ve ridden those almost exclusively since buying them used in about 2012. I’ve gone through two sets of pads on the front in that time. The rear pads have yet to wear out. There is no noticeable wear on either set of rims at the braking surface. Caveats: I live in the Phoenix area, so I deal with very little rain. We do have long descents in numerous places I’ve ridden in Arizona, but other than South Mountain, one has to travel from here to find them. I was recovering from chemo, radiation, and surgery for cancer for about five of those years, and the most mileage I’ve put on in one year since buying the Zipps is 7000. I understand that rims can be made lighter if they do not have to provide a braking surface, and that is weight at the part of the bike where weight matters most other than the tires, themselves.
I have a three-speed with wider tires than I would use on a road bike (the Tarmac has 29mm that measure 30mm inflated, so I’ve overcome years of believing wrongly that skinny tires are faster). The three-speed came with just a coaster brake, so I drilled the fork crown and installed a side-pull caliper brake. It clears that probably 40mm tire just fine without even needing a brake quick-release, so I am skeptical about the argument that rim brakes aren’t suitable for wider tires. Those optimized for narrow rims and tires and small clearances may not be suitable for tires and rims like those on the Tarmac, but others exist that would work fine, especially with a brake quick-release.
I will continue using the rim-brake bikes mentioned above without any concern for my ability to stop using them. I will continue to enjoy the advantages and not be much concerned with the disadvantages of disc brakes on my bikes that have them. Our tandem has a Dura-Ace caliper brake on the front and a cantilever brake on the rear. I wish it had discs, instead. Our loaded touring bikes have cantilevers front and rear. I wish they had discs, also. The extra stopping power of discs and the ability to do so without overheating rims makes discs the choice for heavy braking needs such as on a tandem or loaded touring bike, especially if long descents will be encountered..
Thanks for all the detail. Very helpful.