I generally have a few reservations about technical articles written by Leonard Zinn (USA - Velo magazine).....but see a lot of things in this article that seem to match my feelings on the issue - what are your thoughts???

http://velonews.competitor.com/2012/08/ ... kes_235280

Zinn is correct in relating the shortcomings of cable/hyd road discs.

The reality is that the aero drag is SFA comopared to what the human body is. As is the weight, especially when you look at the % overall. The release from SRAM will be interesting, as it will be the 1st from a big/serious player.

Having ridden road discs for over 12,000km now on a road bike (drop bar, not a flat bar commuter), I have never had an issue with too much braking, too little braking, lockups (even in the wet) etc.

I have run BB7's on 160F and 180F rotors, and am currently running a TRP Parabox 180F & 160R with Shimano IceTec rotors.

Yes, there is a weight penalty.
Yes, there is an aero diadvantage (but really ...)
Yes, there is OUTSTANDING modulation and braking in the wet. Actually all the time.
No, I have not had an issue with overheating brakes. Even on repeated heavy braking for switchbacks on a 7%+ downhill run (repeated braking from 70km/hr to 20km/hr)

Yes, it is not for everyone.

BUT there are too many people postulating and whining without having tried a ROAD bike with discs.

The appearance of disc brakes on road bikes has nothing to do with 'performance'. Disc brakes sell bikes.

NM

Disagree mostly.-- of course with disk brakes come new frames.

The riding I do on the mountain would be very hard to accomplish without the power and modulation that comes from disk brakes. All the mountain riders I know are excited about road disks. Seems also disks solve a lot of problems associated with carbon rims, and would allow on high performance profiles for the aero disadvantage to be overcome by not needing to design in a brake track.

The primary disadvantage seems to be the weight penalty: it will be hefty. And more so at competitive levels, nobody wants to be sliced up by a rotor. I imagine in 10 years the majority of riders will be on disks, with some weight conscious ones on rim, similar to mountain bikes.

Unless discs make it into the pro road ranks they will be seen as kinda dorky. Like riding with a rear-view mirror, spoke protector disc or spd shoes.

For that to happen they will need to show a real net advantage over traditional rim brakes.
I haven't seen anything that suggests that even a redesign of current technology would provide such an advantage.
Rather, they appear to generate more problems than they solve.

I'm interested to see if disc brakes will work to reduce "rotating" mass and provide significant acceleration benefits in wheels to come...

I can't recall but what were the teething problems MTB's had to face when discs started on the scene & how long did it take to iron out the initial issues?

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"It never gets easier, you just go faster..." - Greg Lemond

"Because technology alone is a poor substitute for experience." - Richard Sachs

Overheating and brake fade, sticky pistons (mostly on old Hayes stuff), weight, modulation... mountain discs were really not very good for quite a few years, at least not relative to what we have now. I remember boiling brake fluid and glazing pads far more frequently. The latest batch is incredibly good, though. The new Shimano brakes, XT and XTR, are damn near perfect in terms of power, modulation and heat dissipation. Incredible bits of tech.

I hate braking on carbon rims, but also like riding carbon rims... plus I come from a dirt background and the gap in brake performance between my XC rig and my road bike is enormous. So I'm excited to see what the big companies can come up with. There are certainly some interesting things that will be made public at Eurobike.

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This hasn't been talked about much, perhaps the only hinting at it I've seen from the industry came from Damon Rinard, but I have very serious doubts that moving the brake track from the rim is going to do anything substantial for aerodynamics. We've reached a bit of a plateau in terms of rim design, where the current crop of fastest wheels (all exceptionally close) don't have parallel brake tracks, Mavic has their little filler covers, Bontrager has tires with little wings to smooth out the profile, etc. I think we're beginning to see a flattening of aerodynamic gains, everything is starting to look very similar in the grand scheme of things.

From Damon when people were asking about the P5 testing: "We just got back from a tunnel trip and it's not looking pretty for disc brakes... I can't reveal the numbers yet but I'll just say that adding a front disc brake and caliper to any "superbike" would add enough drag to make it slower than some road bikes... "

If true, that's an enormous amount of drag from just a front caliper. I'm watching the development, but I'm skeptical at this point.

Personally I see road disks as the HDTV of the bike industry. When HDTV came out people came in to buy an HDTV and walked out with new speakers and a blu-ray player, new cables, wall mounts, etc. this lead to big money for the TV industry. Right now I feel that with high end aluminium and Carbon Fibre trickle down, there is not much more that road bike manufacturers can realistically throw at the market. The recent introduction of the Aero and Plush categories of bikes showed the need for more models to make mainstream bikes more marketable.

As weights drop on plush and aero bikes the differences again become negligible. The bike industry needs a new paradigm to drive sales. Whether or not discs improve bikes is secondary to the fact that they demand all new frames, forks, wheels, and gruppo components. They will be heavier and less aero at first giving the bike industry another decade or so to fine tune the products, eliminating weight and improving aerodynamics year over year. In another five years or so you will start to hear and see rumblings about road suspension, which will be the driver of sales the following decade. The UCI weight limit is the friend of the bike industry it gives them room to change to bikes without fighting over grams.

Zinn wrote "I believe you can find brake-cable housing that combines coaxial strands to prevent compression of its length with spiral winding to prevent bursting."

Who makes that?

he's complaining about aero dynamics and weight? Zinn.... Son I am disappoint.

I've run discs (hydro) on my commuter for over a year now and there's no way I'd go back to rim brakes. It's not even close.

Once the (decent) road frames and wheels start coming to market which are disc-ready I'll be making the switch there too.

People can grumble all they want. I've tried it and I've made up my mind.

why doesn't the cycling industry reach out to the motorcycle industry for their expertise on this matter? motorcycles have been using discs since the late 60's. if anyone can solve these potential "problems", it would be a company like Brembo.