I'm surprised the discussion around road disc brakes has taken this long to raise my ire high enough to overcome my apathy and lethargy, but it finally has. As reported on VeloNews, Bike Rumor, and elsewhere, Zipp has introduced a disc version of their 303, both in full carbon clincher and tubular versions. As of now, it is not a disc-specific version of the rim, leading to much speculation about future generations of the wheel. In addition to this the Ultra New SRAM Red is going to 11, and will feature hydro disc brakes.
I don't know why, but I cannot help reading the comments sections on these blogs. Never has it done anything other than make me angry at the ignorance of those readers who have enough energy and misguided passion to spew their filth, comfortable in the anonymity offered by the interwebs (at least on Bike Rumor; VeloNews comments are tied to a Facebook profile, which is better than nothing, but close enough to anonymous). I spent a solid half hour reading through the comments of readers as they vomited about the inferiority of road discs, how they are a solution to a problem that doesn't exist, and how unfair it is that SRAM has the audacity to introduce new products when they just introduced new products LAST YEAR. I'll address these in turn:
1. The Inferiority of Disc Brakes on a Road Bike
The argument usually goes like this, "I once read this blog post about a guy who crashed really hard because he was riding a road bike with disc brakes and they failed." Most often, this argument is backed by an argument about issues of heat dissipation.
The issue of heat dissipation is a valid one, and one I don't believe has been totally addressed by the road disc technology we've seen thus far (I do not include the Ultra New Red hydros in this, because I haven't read any reviews of them yet), but heat dissipation was long ago addressed by mountain disc technology. I cannot recall the last time I read a negative review of a mtb brake due to heat fade, although that was a frequent issue with first and second generations of mtn hydro brakes. If road brakes are not there yet with respect to heat management, they will get there.
How? My predictions: consumers or brands or both will recognize that a 140mm rotor on the front is not adequate. It may provide plenty of stopping power, but the shorter circumference (read smaller surface area, which is directly related to heat dissipation) and decreased mass are an insufficient heat sink. 160mm is will be the standard, at least in the front where it matters more.
Shimano has spent considerable resources developing heat dissipation technology. By almost all accounts, their mtb disc brakes are excellent. Other brands will follow suit, developing things like finned rotors, mixed-metal rotors, and radiators on calipers. All this technology exists and has been proven on mtb discs. It's only a matter of time before material and manufacturing technology advance enough to make weights acceptable for road bikes.
2. The Disc Brake Solves a Problem That Doesn't Exist
Argument: "I can already lock up the tires on my road bike with the caliper brakes. Why would I need discs?"
Superficially, the argument is sound - road calipers are already strong enough to lock up the tires - for the science geeks out there, there are two types of friction: static and sliding. Static friction means the parts are stationary relative to each other. Sliding friction means they're...well... sliding. Simplistic explanation, but adequate for this discussion. The force of static friction is always greater than the force of sliding friction, i.e. if you're locking up your tires, you are not slowing as quickly as possibly, no matter what.
The problem with this argument is it assumes an ideal environment, in which things like moisture and temperature are not considered, and in which the only variable being considered the the power of the brake. It's just an inadequate way of evaluating the performance of a brake.
Consider modulation. This is the ability to apply the brakes such that you do NOT lock up the wheels. Thought of another way, it is the ability to finely adjust the amount of stopping power. Better modulation means finer control over that power; worse modulation means poorer control over it. In the olden days, when brakes had poor modulation, it was said they were either on or off. Modulation is arguably a more important performance variable than power. As many point out. nearly all braking systems on all bikes are now powerful enough to lock up the tires. Other performance variables to improve are durability (never a high priority because if something lasts forever, you only sell it once), and modulation. So, modulation gets better, and we're all safer and happier.
This argument also disregards the other components affected by moving the brake from the rim to the hub. Most importantly, if a rim doesn't need a brake track, it can either be made lighter, or stronger at the same weight. Either is better, as you're moving mass from the outside of the wheel, where it's harder to get it moving, to the center of the wheel, where it's easier.
I know what you're going to say here. "They still can't make a disc wheelset and hydro disc brake set that together are lighter than current road wheels and brake systems." True, but they will. If there is an Axiom of The Bike Industry, it is that parts will always get lighter.
3. How Dare SRAM Introduce New Products When They Just Did So Last Year
What? Are you fucking kidding me? I was blown away by these whiners out there. "I'm so pissed because I just bough New Red, and now there Ultra New Red, and my Old Red sucks." No, it doesn't. Your 2013 Red is exactly as good as it was when you bought, minus the usual wear and tear. It is your perception of it that changed. New products come out annually, and it's been that way forever in the bike industry. Maybe that another Axiom of The Bike Industry: brands will always come out with something newer and better.
What's even more interesting to me is that the arguments and complaints themselves haven't changed at all. Every time a gear is added, people bitch because their old stuff won't work with new stuff. Every time a new tool is required, mechanics bitch because they need to buy a new tool. Every time a new technology is introduced, people are adamant that it CANNOT be as good as the old, tried and true technology. Read "The Dancing Chain" by Frank Berto. People bitched when they were figuring out how to offer two gears on a fixed gear bike!
Look, I'm not an early adopter. My mtb had to be stolen before I considered moving to a 10 speed setup, and the same is true of my road bike and 11 speeds. I'm not a racer, and on those occasions when I decide racing would be a good, if misguided, idea, I'm not nearly fast enough to push the performance envelope of my equipment. For a guy like me, and for 98% of the bike industry, this is true, no matter what we or the market departments tell us. It just. Doesn't. Matter.
But, as I have said in previous posts, things are better now. Even when we disregard mushy variable around performance, we can agree that it is safer to not have to move your hands to shift your gears or apply your brakes. Conceding diminishing returns, it is easier to pedal a lighter bike. Metals and manufacturing are improved, so pieces like spokes and rims are stronger. They're better. Taken care of properly, there is not reason a bike of reasonable quality, with the appropriate maintenance, cannot last forever. Yes, by the time you die, the only pieces of original equipment might be the frame and handlebars, but hey, it's the same soul, isn't it?
Just ride your fucking bike, OK? Just ride it, and love it.