Friday, April 11, 2014

If Ads Were Honest

If advertising were honest, most cyclists would realize that they already have disc brakes. Rim brakes functionally are disc brakes, and most road bikes have had them for generations. The disc brakes that are based on motorcycle and automotive designs, with their little 140 - 160 mm rotors, are in many ways inferior to the brakes bicycles have been using for decades. In wet, muddy conditions, like those encountered by mountain bikers -- the "new" designs offer some benefits. But for road cyclists, there are at least as many drawbacks as there are benefits to the new designs. The small-diameter discs heat up much more quickly than the 622 mm discs we call "rims." That heat will warp the little rotors, which are only a couple millimeters thick, in no time. Cable-operated versions have inferior modulation, while hydraulic systems are supposed to be better in that regard. Then again, overheating with a hydraulic system can boil some kinds of brake fluid, leading to no brakes at all. The only thing wrong with good-quality rim brakes is that they are simple and they work. So how could we market that?

Likewise, an honest ad about the "new" disc brakes might look like this:

If advertising were honest, people would know that carbon fiber forks with massive, tapered steerers and corresponding head tubes are the result of past failures and trial-and-error. Carbon is great on paper -- it even blows away steel in lab tests. But carbon frames and forks are a "work in progress" being tested on people who are paying a premium for the privilege of being used as crash test dummies. How could we advertise that?

Don't expect to see any of these ads in cycling magazine anytime soon.


  1. Hi Brooks, you have a great blog and I am sure I will end up reading all your posts. So well researched and written!
    Most of your observations are well founded. I worked in bike shops in the 70s and 80s and have been watching how so much is changing now. I sigh every time I have to accept another cog on my cassette. I'm up to 8 and hoping that number will remain available for another decade or 2.

    Just like the cassette hub with the outboard bearings (vs freewheel hubs prone to bent axels) I think the emergence of disc brakes is a good thing. I have found braking to be much improved, especially in wet weather. Is brake overheating or rotor warping a real problem with them? It has never happened to me in several years of using them. There are different sized rotors to handle the task required.
    A worn disc may overheat but is easy to replace. A worn rim may cause the rim brake track to collapse, with crashing a possibility when the tire explodes off the side. Living in rainy portland OR, before I went to disc brakes I would replace 2 rims a year. The disc is not tasked with the crucial job of supporting an inflated tire like a rim is. And rim replacement is of course a much bigger deal.

    There is the issue about beefing up a fork to deal with the braking force- not so good for a light road bike. But having a rear disc brake on that same bike would improve it when reliable stopping power is the goal.

    1. Thanks, Drew -- always good to get a different perspective.