Jim’s Tech Talk
By Jim Langley
Last week I introduced my friend Andy, a recent retiree looking for shopping advice. He asked whether on his new – and probably final dream road bike, he should get rim or disc brakes. Catch up here if you missed the story.
I gave Andy my advice and asked you to chime in with your recommendations. This resulted in so many great points about disc and rim brakes, that I’m devoting this week’s issue to your awesome feedback. I edited some a little for brevity and only shared a few thoughts where I felt they would add value. But mostly, this is all you.
“My problem is not stopping, it’s going”
I’m starting with Ron Sowers’ comment because I got a kick out if it and he’s not the first to share this roadie sentiment with me. He says,
“Marketers for the component companies sole job is to convince us that our life will be better if we buy their “new and improved” components. What we actually need is “new and improved” health so that we can ride faster and farther. As to disc brakes- the K.I.S.S. principle certainly applies here. Do we really *want* to carry extra weight on long rides or up hills? My problem is not stopping, it’s going. And do we really *need* a more complicated bike? I don’t think so.”
No More Arm & Hand Fatigue with Discs
Multiple riders pointed out another advantage of discs.
Stephen P Fitzmaurice explains,
“I sometimes ride in mountainous areas. The additional stopping power of disc brakes on long descents is very welcome. My experience is that there’s far less exertion to achieve the same result meaning the muscles in your forearms won’t be worn out when you reach the bottom of the descent. Of course, some of us don’t bother with brakes on descents but I’m older and a little more cautious.”
Robert T Brandenburg agrees,
“I second the comment about fatigue. I am in my mid 70’s. Our group takes a week for a bike camp in the mountains of North Georgia. Without disc brakes, I often felt fatigue in my hands and forearms. Now I can lock up both wheels with two fingers on the disc brakes.”
Tom Pennello adds,
“I’m quite in agreement. Long mountain descents can be a real pain with rim brakes — your hands are tired from pulling hard on rim brakes with mediocre stopping power. There are hills here in Santa Cruz (where Jim lives) that I avoided descending just for that reason. Not any more! With disc brakes, it’s single-fingered braking all the way down! I’m never going back.”
Rim Brake Parts Availability Concerns & Injuries from Rotors
Mike points out,
“You’re holding on to rim brakes and the industry won’t let you for long. I ride 5,000 miles a season and love love my Trek Madone with rim brakes on carbon wheels. However when I ride a road bike with disc brakes I can see the train coming. We will have parts problems etc. in five years and rim brakes will be in the minority. We need to get on the disc train and help to improve them. Just my thoughts. Ride on my friends,”
“There are thousands of bikes with rim brakes that if parts become harder and harder to obtain will be rendered useless. Right now a typical 10 year old bike, for example, could be quite viable and usable 10 years from now. Might not be able to say the same for a rim brake bike bought today. There will likely be a viable cottage industry for rim brake parts developed.
Most people I know that have multiple bikes also have multiple wheel sets. And on occasion swap wheels from bike to bike for various reasons. For those people discs and rim brakes adds layers of complexity, cost, inventory, tools, storage, etc. For some these won’t matter.
Also, adjusting a rub out of disc brakes can be frustrating (a real PITA). A novice with minimal skill can be quickly shown what to do with rim brakes, no so much with discs (and forget bleeding hydraulics).
I’m not a Luddite and, in fact, often an early adopter. If cost was no object or I was starting out I’d probably be on disc brakes. Barring a lottery win, I’ll be sticking to bikes with rim brakes.
This situation is somewhat analogous to cars with automatic and manual transmissions. You can find a new car with a manual transmission but choices are quite limited.”
“I am not really concerned about finding parts for rim brakes. I can still find parts for 50 year old vintage bikes when I need them.
One other thing to consider…disc brakes are more likely to cause a severe injury if one goes down. Pros (and non-pros) have been seriously cut by the rotors).”
I haven’t seen any good proof that disc brake rotors cause lots of injuries in crashes, Walt. I know they were blamed a couple of years ago in one pro race, but afterward it seems like most experts agreed the rotor did not cause the injuries. Disc brakes have been wildly popular in mountain bike racing for many years now and you don’t hear of many injuries. But, your other point is spot-on. Parts availability for bicycles – even old, obsolete parts is now much less a problem with resources like eBay.com. And it’s common for companies to step-up and make replacement parts for obsolete products like Chuck said.
Thoughts on Through Axles (aka “thru” axles)
Oro Valley Dragonman writes,
“If you get disc brakes, go for thru axles as well. That is the one thing that can spoil the disc brake performance/experience: the wheel not exactly centered. With rim brakes, this can be compensated for, slightly, but with discs, the margin of error is greatly reduced. Thru axles ensure the wheel is always properly positioned.
My one other point is, that there is a new wrinkle in the rim brake: direct mount brakes, that attach to the frame on either side of the wheel, as opposed to a central bolt. Direct mount brakes provide almost as much stopping power as a disc brake. Almost. Except in the wet conditions mentioned.
While direct-mounts are a great alternative to discs, once you ride discs, especially hydraulic disc brakes, you will probably never want to ride anything else again. The lack of maintenance, other than replacing worn pads, is a great owner’s point.”
Richard Henley concurs,
“One overlooked point, is the advantage of the thru-axle hubs found on disc brakes, which is measurably more “solid” than even the best quick-release based wheel connection, at least in my experience. This is a feature I appreciate, and frankly I’m happily willing to carry a 5mm Allen wrench, to obtain that improved performance.
In the past, I have had the disconcerting experience of my front wheel “plowing” due, in part, to the flexibility of the quick-release mounting system. With the thru-axle the wheel-to-frame connection is significantly more solid – and that extra stability feels good, especially at the edge of the performance window (which I try to avoid). Disclaimer: my current bicycle is equipped with Campagnolo Super Record 12 hydraulic brakes and ENVE 3.4 wheels, with DT Swiss 240 hubs. All my best to everyone.”
One small point, Dragonman, even though they were a little rare, direct mount brakes have been around for a long time. They were on my 70’s Peugeot, for example. You’re right about their added braking power.
And, Richard, there shouldn’t be any “flexibility of the quick-release” on road bikes. If there is, it’s almost always that something’s wrong. It might be a broken axle in the hub, a poor quality quick-release or even a cracked frame/fork dropout. These issues can cause crashes so they should be inspected and repaired as needed.
Seized Disc Brakes
Leon Webster raises a couple of interesting disc issues,
“I used to have a Tern folding bike that had hydraulic disc brakes, and I didn’t like them. If the bike sat for a couple of months, the brakes would seize up, and there was, as far as I could see, no discernible benefit to them. I later swapped them out for cable actuated discs, and still didn’t feel like they were any better than rim brakes.
I tour quite often, and think about what would happen if I needed to repair my bike in East Nowhere using parts I could get only at the local Walmart, or the local bike shop, or at the local welding shop (had a rack repaired that way once), or scrounging in a local junk pile. I much prefer the simplicity of rim brakes. Of course, I am also quite happy with my triple crankset and 12-32 8-speed cassette. So I guess I have become a retro grouch in my old age.
Leon, you might be interested to learn that on hydraulic brakes that use DOT brake fluid, it’s possible for expansion to occur inside the hoses over time seizing up the brakes exactly as you described on your Tern. The solution is to very slightly bleed off some of the fluid to restore proper braking.
Discs and Organized Tours/Rides
Greg Conderacci shares,
“I bought a 2018 Cannondale Synapse last year… my first experience with disc brakes after a half century of riding rim brakes. Like Jim, I have mixed feelings. I like the extra comfort of wider tires and the increased confidence of superior braking. I contemplated riding PacTour’s Ridge of the Rocky’s Tour. It seemed like I had the perfect bike for it.
And then, I read this comment on their website: “More road bikes are using disc brakes. They work great except when the rotors get bent in shipping and the brake pads rub or the brakes leak fluid. If you are using disc brakes you should know how to align the rotors and change the brake pads. If you have hydraulic brakes you should know how to maintain the fluid levels. Our spare team wheels do not have disc brakes or through axles.”
There was a lot of wisdom there. With rim brakes, pretty much any wheel will work on any bike. Not even close with discs. And what if you leave your through axle by the side of the road when you load your bike into the car? (I bought an extra just in case…)”
Thanks, Greg. I know that PacTour also discourages the use of low spoke-count wheels because they often fail and may require special spokes and tools to repair. Your tip to purchase and carry a spare through axle is much appreciated.
Disc Wheels Swappability
“Like Andy, I am a recent retiree. I bought an “endurance bike” this last year. The only option was disc brakes so that is what I have. However, I agree with Jim on the decision. Yes, the stopping power of hydraulic is welcome on the occasional big descent. But, IMO, the added complexity of a disc brake bike is not worth it for most riders.
One advantage of disc brake bikes I did not see mentioned is that these bikes can readily accommodate different rim widths without the need to adjust the brakes each time the wheels are swapped out. I have two sets of wheels for my new bike each with tires for different purposes (road/gravel). The second wheel set I bought did not have the same rim width as the wheels that came with the bike but that’s not a problem, I can easily swap wheels.”
Andy Could Get a Bike that Takes Both!
Tom in MN shares a great tip,
“I just saw that Wilier makes their NDR series of frames that allow both rim and disc brakes. I did the same with a semi-custom Carver Ti frame last year so I could keep using my existing wheels, but upgrade to discs in the future if I wanted (with a fork swap). Many frames with dropout inserts like Paragon sliding ones will also allow for this. So you don’t have to decide now.
I like the TRP Hy/Rd calipers with the simplicity of cable actuation but with automatic adjusting of hydraulics. Also means not replacing your levers when switching to discs.”
Wow, an excellent have-your-cake-and-eat-it-too-solution, Tom. Thanks! I especially like knowing that some manufacturers realize that discs for roadies is not a slam-dunk. It would be nice if the whole industry adopted this approach. Here’s a photo of a Wilier NDR. Look close and you can see the provision for direct-mount rim brakes. Nice!
Universal Compatibility of Rim Brake Wheels is an Advantage
“I have a mountain bike with disc brakes and would not want anything else since I often ride in wet muddy conditions. That being said, my wife and I have several different road bikes we have purchased over the years and love every one of them. One of the things I really like is if one of us has a front wheel problem, I can pull a wheel from any other road bike and slip it on. On the rear I may have to change the cassette but the wheel will fit. I have literally had to do that on the night before a century ride last year when checking out the bikes we were going to use I found a crack around a spoke hole.
There are millions of road bikes with rim brakes still on the road so even if you can’t buy a new bike with rim brakes in the future, parts will be available for the existing market for a very long time.”
That’s an important point, Dave. With disc brake bikes, wheel compatibility is more challenging due to the bikes often using proprietary frame and through-axle designs. For couples buying new disc-equipped bikes, it could be a good idea to make sure the bikes have wheels that are fully compatible between bikes.
Opinion: Discs are Better for Avoiding Crashes
I have a rim brake road bike and a relatively new disc brake road bike. I mostly ride flat lands in SE Texas. But I also normally ride in fast club rides. I like the confidence I have in disc braking when there is a sudden need to stop in the group. Two years ago, a rider in front of me on an open road slowed suddenly without warning. I closed on him too fast and could not brake quickly enough with my rim brake, carbon-wheel bike to avoid contact with his skewer. I did an end over end and landed on my shoulder on the pavement. Fortunately, I walked away without any damage except for a slightly sprained wrist from holding onto the handlebar the whole time. Truthfully, the results may have been the same with disc brakes. But I think there is a good chance I could have slowed enough quicker to keep from flipping over. All things considered, I am an advocate for disc brakes.”
And, William Kennedy adds
“Disc Brakes! I do a lot of charity bike rides and so, if it’s rainy, I have to ride and the increased stopping power is appreciated. Also on these rides, the experience level of riders varies greatly. The ability to make a sudden stop with discs is a plus.”
Disc Problems and Issues
“I only have discs on my MTB bike. With all the aggravation they cause me, I don’t want anything to do with them! Every ride I do, I always have to keep adjusting them, as they keep on rubbing and making noise. (On those rare occasions when I get them to be quiet, I squeeze the brake lever and the wheel keeps spinning!!!) So, until someone comes out with a hassle-free version (for us non-techies) I will stick with rim brakes on my road bike.”
And, Bruce Miller weighs in,
Last year I purchased a new road bike and chose hydraulic disc brakes (the LBS owner’s recommendation).
Pros: stops sooner when wet; better braking on downhills
Cons: more expensive to ship the bike and maintain the hydraulic fluid; slower to change flats
Would not go with disc brakes if I were to choose again.”
Bob Wells adds,
“I found your reply to your friend spot on, Jim; I couldn’t have said it any better. Road disc is being forced on the consumer in yet another planned obsolescence ploy by the industry. To me, it’s an answer to a question I’m not asking. Mountain, cross, gravel? OK, sure, those bikes are heavy anyway. The only performance increase that manufacturers can make a case for is slightly better wet conditions braking. Possibly increased wheel stiffness with the through axles, but how does neutral support feel about wheel changes in a crit with those things?
You aren’t solving problems with discs, you’re just making a new set of problems that’ll need new solutions. Again, if I can lock up my wheels with my rim brakes, stopping power is not my issue. I find the new Cervelo S5 an extremely appealing bike, except for the disc-only braking. Cervelo will not be selling one to me. Kudos to Trek for continuing to offer a choice to their consumers (for now).”
Discs Excel for Descending, Wet Weather and Big Riders
JP comments on his new disc-equipped Cervelo,
“I just added another road bike last week and it was a Cervelo R3 with disc brakes. The main reason I even purchased the bike was for the disc brakes for riding in mountainous areas. We have a number of steep technical descents where you really can’t use carbon wheels due to the heat build up. Even aluminum brakes surfaces have been known to get pretty warm.
If you’ve ever been caught in a rain storm while descending these types of roads you’d be really happy to have disc brakes. I have other bikes with Dura Ace, SRAM Red and Campy Super Record brakes. They are pretty good with stopping in wet weather but I’d much rather have the additional stopping ability with disc brakes. Plus the forks on this bike can easily handle much wider tires. The new bike rides, really really well.
The Cervelo has the quick twist thru axles and they can actually be removed faster than traditional skewers so no issue there. You just make a quarter turn and pull them out. Very fast and simple.
I learned how to do maintenance on hydraulic brakes while building up a gravel bike. It’s just as simple to maintain as mechanical braking if you have the experience. I found them easier to true than my mechanical brakes… plus there isn’t any brake squeal that I occasionally get with my carbon wheels when the brake pads aren’t toed in very well.
Maybe the real issue is discs are just different than traditional systems and a lot of folks just don’t care for different when they are happy with what they have? I was actually wanting something different. I agree that I probably would not opt for disc brakes if I didn’t ride in hilly areas.
My only complaint and downside I have with the disc brakes is the whole system adds some weight to the bike. I suspect that in a few years that will be offset with additional engineering, and even some new materials. We’ll see!”
“I used to ride Campy rim brakes until I was finally able to buy a custom road/cross bike. I was lucky enough to be buying the bike three years ago when SRAM finally got their red hydro disc brakes worked out. I will never go back to rim brakes. I ride nothing but the foothills/mountains just west of Denver and Boulder, and rarely ever ride flat routes. The disc brakes require less force to slow down and enable modulating that can’t be done with rim brakes while descending these many steep roads (at least in my opinion).
Also, I’m not the typical roadie, and weigh more than most skinny roadies do. Disc brakes are a godsend for us heavier riders. My hands used to cramp up from long descents at high speed which for some isn’t probably an issue, but since I am usually faster than others, (As “gravity” loves me) I need all the help I can get in order to slow down before turns/corners. Now I wait for Campy to drop the price of their disc brakes. So, one day I can return to the shifters I love, but will live without in order to have the added braking power of the SRAM disc brakes. To each their own, and I’ll take disc brakes until they come up with something better.”
In closing, a couple of readers mentioned in their comments that their rim or disc brakes don’t work well – suggesting that that type of brake is flawed. When I hear that someone’s brakes don’t work well, I worry about their safety. So, for anyone in this situation, I urge you to have a professional help you with your brakes.
Whether they’re rim or disc brakes, they have to be installed and adjusted correctly in order to function properly. If your brakes aren’t working well, it’s highly likely that a pro can fix them. So for safety’s sake, please don’t assume you have to live with bad braking. Get expert help.
That’s a wrap. Many thanks from the RBR team here for all the awesome feedback, and from Andy who is still kicking clinchers but will soon pull the trigger and buy his new road machine.
Ride total: 9,157
I’m making the call here…discs will become really popular on mid and high end bikes then in a few years we’ll see carbon rim tech improve and companies will come out with new bikes that ***use the rim as the disk rotor!!***. Then we’ll all have to buy new bikes to take advantage of this lighter, simpler solution. People will wonder why brakes weren’t always this way 😉
Raleigh Fehr says
After skimming through all the comments, there’s one issue I didn’t see raised. We were on a group ride on a particularly steep and long descent. One of the riders wound up blowing a tire on his carbon wheel and rim brake setup. From what we could tell, it appeared to be attributed to a heat buildup by riding his rim brakes down the descent. On inspection, all of our rims were extremely hot following the incident. I believe this is something that wouldn’t have happened with disc brakes.
Jim Langley says
You are 100% right, Raleigh. It’s true that blowing a tire from heat build-up in the rim from excessive braking with rim brakes is a non issue with disc brakes. Thanks for making that point. Riders with rim brakes need to realize that on long downhills, it’s unwise to “ride” the brakes. They need to “pump” the brake in order to allow the rims to cool in-between braking.
Chris Boucher says
I’ve retro-fitted cable activated Avid BB7 after the Shimano BR-M6000 original calipers failed twice. The clam design’s central seal is broken by the action of the pads gradually forcing caliper apart. Once the fluid hits the pads and rotor the brakes fail – totally. The only solution is replace the caliper and pads.
I read several comments about disc brakes’ superior stopping power, but only one comment about their superior modulation abilities. In my experience, modulation is the key advantage of discs over rim brakes. Sure, any brake can probably lock up your tires, but this isn’t the best measure of braking quality, because it’s actually dangerous to lose control like that. With discs, I can precisely control and vary the power applied to the brakes and there is a much wider range of usable lever play with discs. I’ve actually only locked up my wheels once, in a “panic grab”, with discs, whereas it’s happened to me many times on rim brakes. As others did mention, the amount of force needed to brake effectively using discs is far less than with rim brakes, As to adjustment and maintenance, I have 10k+ miles on my Domane 6.9 since 2016, I’m still using the same pads, and the lines have never needed bleeding. Only time I get noise is when riding in the rain.
Have had discs and rims on my MTB for years- sometimes swapping on the same bike over time. More recently riding road discs. Well set-up, I really don’t see much difference in dry conditions but discs are much better on MTB’s in the slop. Difference on road bikes is much less since the small tires quickly become the limiting factor in stopping distances (locked wheel skidding).
IMHO- Differences in setup are greater than disc-vs-rim. I ride at 175# and can lock up my HED rim brake wheels with Ultegra calipers & KoolStop salmon pads in the rain. Of course, discs will do the same. OTOH- Trying to stop with worn rims and old, glazed pads can be downright scary. But then I’ve had discs fail me riding old glazed pads…or after I got sloppy and let oil or lube drip onto my pads/calipers.
Point is- For safety’s sake whatever brakes you choose should be set up right and well-maintained.
Agree 100%. And I also ride discs on my MTBs.
Road discs are a viable option, but the overhype of road disc brakes is nuts.
Mr. Versatile says
I started post high school riding in 1963 (I think). From the late 60s through the early 80s I was a cat 2 roadie. I’m 76 now & in all those years I have never felt the need for any kind of brakes other than those I’ve used. If you scroll way up to the 1st post on this thread-I agree completely with whomever wrote this.. I had a bike with disc brakes & they are indeed very good, but I don’t need them. I sold that bike. I’ve ridden some pretty long climbs with long, curvy decents including Mt. Lemmon in Arizona, mountains in Ca, Utah, through the Rockies, & the Blue Ridge Mts. I had no problems stopping nor have I had any fatigue in my hands & arms. Lest you think I’m a rider that weighs 140#, I’m 6’2″ & shamefully, a bit over 200″#. I make purchases based on needs rather than wants. I neither want nor need the aggravation of tinkering with discs, nor do I need their admittedly superior stopping power. When things get a little stale, bike mfgs invent new things to intice more purchasing. What’s next? Handlebar streamers? Maybe high flange hubs will make a comeback. Centerpull brakes, foam rubber seat covers, plastic or unpadded cloth bar tape might have a chance, too. Disc brakes are not a fad. I’m just saying…I don’t need them.
I agree 100% with your all comments, especially manufacturer motives. I’m almost 60, been cycling since my teen years. I similarly have gone up and down many mountains, but around southern France and Northern Italy and have done perfectly well with my Campy Chorus 10 speed carbon bike (or 6, 7 and 8 speed steel bikes before that) – and was consistently among the top 3 finishers in large groups flying down the slopes every time.
In hindsight – I was foolish perhaps to go that fast on those straight and technical downhills.
Like you, I don’t see a need, for me, for disc brakes. However, I can understand that certain cyclists may have carpal tunne issues or weak grips or simply don’t know how to brake during long descents, and would benefit from disc brakes.
Good points, on Disc Brakes issues, and even as of late , you see many pro road racers dismissive of a hydraulic disc bike.(think of the GC riders, climbers, hilly terrain aces still on rim brakes) I can see how they stop faster, but so many PIA issues for most consumers, and for active amateur racers, I do not like the idea of less than pro racers with disc stopping power in their hands, what kind of new crashes will we have due to some with rim brakes vs others racing with discs? Rapid deceleration crashes? Close knit racing packs have you racing all out and no, with threat of crashing a leg into some guys rear wheel rotor? This is for sure a new spike in bike technology to generate new bike sales, but at what cost? Look at how sophisticated road bikes have been running even for pros, racing with calipers , with advanced compound brake pads, AND at minimal weights, So lets keep the disc brakes on Mountain/downhill bikes.
Rando Richard says
I have several carbon fiber road bikes, all with rim brakes. Some are more than five years old and still running strong! But the thing I dislike about most of them is that the tolerances of “older” bike frames were designed around the narrow-minded idea that a 23mm-wide tire was the only good size. These days I am trying to run 28mm rubber, and on some of my frames, I cannot do this. The worst offender has the rear brake bridge too close to the tire (yet there is plenty of room near the fork). The rear Ultegra brake has plenty of adjustment, but the engineers were trying to make this Trek endurance bike look too “racey,” by not leaving extra room (when they could have…very easily). For that reason alone, my next frame will have disc brakes, so I don’t have to deal with stupid-tight tolerances that the designers built into a frame so it would just “look cool.”
Arnie Mejia says
I’m surprised no one mentioned skidding. Yes, disc brakes stop faster, but only under controlled conditions. Now, it seems to me the braking power of disc brakes is most often needed under last-minute, uncontrolled conditions. I will be switching to disc brakes, but only because of hand and arm issues—not because I expect them to better when I need to stop on dime, so to speak.
Eddy Merckx says
I have both a disc and rim brake bike and I can tell you that I am disappointed that I spent the money on a disc brake bike. First, I am riding around with 1-1.5 lbs more than I should be with disc brakes, which didn’t seem like a big deal when I bought the bike, but in retrospect I would much rather prefer the reduced weight. I will admit that the discs do work great in wet weather, but they are also very loud when the discs are wet… pretty lame and annoying. Brake rub seems to be inevitable, and I have yet to go out on a ride and not hear the ‘ting, ting, ting’ sound of the rotors rubbing against the pads (typically after hard braking pressure is applied and then the rubbing sets in for 10-15 seconds to follow, then it goes away). I am not convinced the braking power is really that much better. I seem to brake just as fast and have just as much control on carbon wheels with rim brakes. Also, disc brakes on a road bike just look kind of stupid to me… they just look heavy and bulky. Rim brakes look cleaner and classic to me. It might just be in my head, but my rim brake bike just feels snappier and quicker than the disc brake bike. I haven’t had a single issue with my rim brakes… can’t say that for the discs. Also, discs are more expensive and more maintenance time. Lastly… KISS. Bottom line… if you want to ride off-road or in the rain a lot, get discs, otherwise rim brakes are the clear winner in my opinion. If you get a disc brake bike you will likely be bummed on your very first ride because I can almost guarantee the brakes will rub.