rubiksoval

And dragging your brakes? For a decade?

Okay, so not a legitimate reason.

rubiksoval

Chinese frames for the win!

AND I can get my BSA bottom bracket.

And "cheap" enough to get a new frame every year if I really wanted (I mean, if my wife let me).

Marcus_Ti

Quoth the Small Ball of Petunias: "Oh. No. Not again."

Dean V

I think rim brakes leave a bit to be desired for riding/racing in groups when it is very wet (carbon rims).
Otherwise I am ok with them and they are what I ride on most of the time.

noodle soup

! year ago I would have agreed with you completely.

My DA 9000 equipped bike was stolen, and I replaced it with bike equipped with 9000 series Di2 and hydraulic discs.

Di2 is awesome, but the hydraulic brakes are mind blowing.

I never wanted disc brakes on a road bike, but now I don't want a bike without them.

HTupolev

I'm not speaking hypothetically about this stuff. Rim wear is just a reality for people who ride outdoors year-round here. A few thousand hilly miles in the mucky wet can be all it takes to burn through a rim, especially if a lot of it is night riding where the lack of visibility demands more braking. For people who ride a single set of wheels year-round, a rim replacement cycle of every year or two is not that rare; there's zero wear in the summer, but extremely rapid wear when it's mucky.

About a year ago, before a group ride, there was a sound like a gunshot. On a wheel that had just been topped off, the thin brake track allowed the hook to separate from the rest of rim in one spot. The rider of that bike is an experienced roadie, and did not "drag his brakes for a decade", he just hadn't been very diligent about checking brake track wear. Similarly exploded rims aren't a rare sight for bike shops in the region.

rubiksoval

Right. You're speaking anecdotally about an issue that will never affect 99.99% of people.

It's like breaking a frame because you put out too much power on the trainer. Or some miniscule factor like that. Sure, it might happen, like anything, but it's so insignificant that it's simply not relevant.

Caliwild

I was slowly being convinced that discs are the future until I tried the Cane Creek EE rim brakes with aluminum wheels... truly amazing braking (in dry conditions).

If I did a lot of high speed descending or lived in Seattle, I'd go disc...

Sy Reene

This seems like the main thrust of the killing off of rim brakes, ie. wider tires.. but to this point, would the engineering redesign of rim brakes be that revolutionary to increase the clearance of tires using the brake release? With everything else mechanically just about perfected, getting calipers to open a bit more for wheel removal seems like someone could figure it out.

Sy Reene

Sorry, but cruising around the LBS parking lot, I can't imagine I'd be that much more impressed with a disc brake's stopping power or feel. ymmv

Kapusta

Speaking for myself.....

If i were still running 23-25mm tires, and running short reach dual pivot calipers, i would probably not really care if I had disc.

However, having tasted the sweet wide-tire nectar on a road bike, I now run tires at least 32mm, preferably bigger. At that point, the rim brake choices are long reach dual pivot calipers (which under the best of circumstances might clear a 35mm tire), cantis, or mini-Vs. I'll take disc over any of those.,,, even mechanical disc.

I just like the way they brake more than rim brakes. Simple as that.

Having spent decades with rim brakes on road bikes and now the past 2 years with mechanical discs on my Fog Cutter, I don't think the difference is huge, but I prefer discs, and I can't see any reason why I would go back to rim brakes. I mean, if there was some bike I lusted over, I would not rule it out for having rim brakes, but I would prefer disc.

spdntrxi

Unnecessary ...maybe. But for me they alleviate a lot of hand numbness I used to suffer and for that alone it was worth it too me. I've gone disc all in (except for eroica bike).. so Road, Gravel and even TT) it was expensive because I sold off most of my wheel sets and had to purchase new ones.. and of course new bikes.

Overall I think they are great.. 1 finger braking is nice, sure I have the disc noise on occasion but it goes away pretty fast. I have many wheel sets already and most don't require me to adjust the calipers. Slap them on and go, even when I have to adjust it's no biggie. I'm glad I did it late last year, the timing was right.

HTupolev

This has been a solved problem since the dawn of time. If there's a big difference between the rim width and tire width, you can just use a brake where the quick-release mechanism fully releases the cable from the brake arms. This was standard practice on wide-tired bikes through most of the 20th century, with centerpull cantilevers and dual-pivot calipers having detachable straddles, and then later v-brakes where you can detach the connecting wire at the noodle.
A similar scheme could probably be implemented on a sidepull caliper, or the QR cam could be made a little bit bigger. Or, you could just spec a road bike with something other than a sidepull caliper, because there's no particular reason that road bikes are restricted to them in the first place.

Wide rims also go a long way toward ameliorating the issue. If the brake pads are set wide because the brake track is wide, they don't need to open by as much to clear a tire of a given width. For example, if you're running a tire that measures 25mm on a modern aero rim with a 25-26mm outer width, you obviously don't need to open your brakes at all to remove the wheel.

Breaking a frame under power is something that's hardly worth thinking about because it's not something that you can really predict or plan for. That's very different from rim brake track wear, which is highly predictable and quite noticeable if you regularly ride in mucky conditions. It's possible to know that you're going to burn through brake tracks rapidly, and that can be a factor when choosing whether to buy a set of really nice wheels.

My point isn't that brake track wear is an important consideration on all bikes. It's simply that brake track wear is one reason that some people choose to go disc on some bikes.
I don't think it's as obscure of a concern as you think, considering that multiple people brought it up.

Dean V

It is figured out.
I have an Emonda ALR5 with the new Shimano 105 group. The callipers clear a 30mm (measured) tyre just fine.

Sy Reene

Awesome.. so this became possible with the 7000 series? Ultegra 8000 groups as well I assume?

HTupolev

The important question is how much wider the tire is than the brake tracks. When you pop the QR on a sidepull caliper, it opens by a certain amount, not to a particular width. So a 30mm tire on a rim with an outer width of 20mm is a much bigger issue than a 30mm tire on a rim with an outer width of 27mm.

With gravel cycling and whatnot this becomes a bigger problem, since people don't use 36mm-wide rims for mounting 40mm tires.

79pmooney

But if you ride any real miles in the spring, fall or winter in the Pacific Northwest with rim brakes, rim wear is very real. (HTupolev's next sentence was " Rim wear is just a reality for people who ride outdoors year-round here." Next paragraph he describes an incident he was present for. (I've had a thinned rim blow in my garage. I was in the kitchen when I hear the rifle shot. Does that make my experience "anecdotal"? And I've heard the same stories from bike mechanics here. I've retired a bunch of rims that had near nothing left. (I suspect the culprit is the hundreds of square miles of lava in the Northwest. And former lava that is now stones, gravel, sand and dust.

I can get 2 winters out of rims only because I split my winter riding between several bikes.

Ben

79pmooney

I see several posts talking about calipers not releasing enough to clear the tires. A simple solution is to have more than one release. All my calipers have either a release lever or easy to pop bridle. I believe all my brake levers have releases. I have seen in-line releases. Never needed one and haven't noted where I saw them. They are similar to the in-line adjusts I have on several bikes.

Ben

TimothyH

Get on a well maintained mountain bike with 203 mm rotors and you will change your mind the moment you even think about squeezing the levers.

Stopping is frighteningly good. I mean it stops so well it will actually scare you the first time.

After two or three squeezes you will be laughing like an eight year old and getting up as much speed as you can just so you can stop.

I generally don't like to over-dramatize things but the experience for me was mind blowing.
-Tim-

sultanofsuede

Quote:
Originally Posted by daoswald
To eliminate wheel rim side wear-through on expensive rims.
That's really not a legitimate reason.
__________________
Cat 1


this was my understanding as well. if you have a expensive carbon rim that is built for rim breaks, then the break pad surface will not actually rub up against the carbon (it would be on a small alloy section of the rim, no?)

gregf83 

+1. I was wearing out rims in about 18-24 months commuting through the winter. The crud from the road forms a grinding paste on the wheels and it doesn't take long to wear through a rim. I don't see any advantage to discs on my summer bike but for the 4-6 months of wet roads I ride on switching to discs is a no brainier. Consistent braking down hills in the wet and not having to rebulid wheels every couple of years is worth it to me. Zero downsides for the winter.
I'm not sure what it's like to travel with hydraulic disc brakes so I'm going to stick with rim brakes and pickup cheep wheels from all those who convert to discs.

HTupolev

Most carbon rims use carbon brake tracks. That's why there are special brake pads for use with carbon rims.

But it doesn't really matter either way. If you're riding in conditions that eat rims, both carbon and aluminum brake tracks will experience wear.

Bikesplendor

The grinding or scraping-grit sound when pads meet rims after riding in certain sorts of conditions is something that truly bugs me. Like taking sandpaper to my rims, and pressing down hard... I can't stand it. So I end up stopping to clean things up, not only the rims but the pads and the grit embedded there as well. This is tedious and annoying.

In some conditions and situations there is a real safety advantage to being able to slow or stop more quickly, and discs can make a real difference.

My worst accident (hitting deer) would have been avoidable with discs. My second worst accident (being hit by an SUV) would probably have been avoidable as well.

Just being able to reduce speed quickly, especially while riding down hills in wet conditions, but also in other situations, can also be meaningful. Another bad accident (losing control on an unexpectedly roughening downhill) would have been avoidable.

​​​​

SHBR

I dread the day I have to buy a new bike.

Although, I'll probably also say, I should have done this years ago.

Maelochs

I see people downplaying rim wear ... but those people seem to prefer to deny everyone who disagrees than to admit that people in different regions face different conditions.

I have seen a lot of people in the PNW talk about eating up rims in a couple years ... and not all of them were discussing disc brakes (I first heard about it in discussions about wheels.... sort of makes sense.) I have never worn out a brake track ... Even when riding 5-7 days a week, year round, which included the rainy seasons. But ... the rainy seasons were short, while I guess the PNW doesn't have a "rainy season," just rain.

I know when I laid out a fair amount of dollars for a set of lightweight CF wheels I got disc wheels because I don't Ever want to grind through the brake tracks. Those suckers were too expensive to justify if they don't last.

But ... I do agree that in most cases (except maybe serious cyclocross/gravel riding) the brakes can open enough to get a tire by .... sometimes people used to deflate (or not fully inflate) a tire before mounting the wheel to the bike, to avoid the issue.

I know also that all of my bikes have a simple barrel adjuster, and setting brakes is a whole lot easier than trying to index a derailleur on the fly. I pinch the shoes to the rim, tighten down the barrel adjuster with my other hand, then back it off until the wheel spins freely. So for me, rim versus tire width is a non-factor (at least in brake choice.)

I have discs on my work/rain/light touring/gravel bike because in my experience discs are better in bad conditions. I know from experience that discs can offer a Lot more stopping power (and therefore modulation), but i never felt I needed that enough to get rid of my current crop of bikes. But "better stopping power and modulation" would definitely be major factors IMO.