i’d have to try out this combination, but i’m still haunted by one of the first times i went for a ride on my commuter bike (alloy wheels and brake track and 105 caliper brakes), it started raining, and as i approached an intersection and i went to brake, it felt like i had no brakes at all. I ended up riding off the path and onto the grass to avoid going into the street!
haha yeah fair, there are definitely people who would wrap themselves in bubble wrap every time they left the house out of fear of an accident, but that’s not really where i’m coming from here. in my experience having discs on my road bike has been great and saved me from accidents in varying conditions in the chicago area. there’s so many people and so much going on that the ability to quickly come to a stop regardless of the weather is invaluable.
that’s just my experience though, i know rim brakes work well for others and they’ve worked well enough for decades! for me, discs fit my needs and my application better
Regarding rim and disc brake ability to stop: both will, if not careful, flip you upside down. Years ago, on rim brakes, a car made an impossible left turn in front of me. All I remember was seeing a giant silver hood and windshield. I grabbed everything and flipped over hitting the back passenger quarter panel with my back/shoulder area. The driver stopped then drove away…long story. Point is, stopping power of rim or disc is not an issue.
Regarding weight v. aero and how they play in races: I hate the debate. I think it’s way way over thought and over done. More important and decisive is position. The more technical the more important it is. The ability to get in position is the battle, the race, the place where energy management is critical. Obviously, if you are in a good position and still get crushed then there’s more to work on but, I digress.
All that opinion said, I prefer aero over lightweight and disc over rim.
Agreed 
Very common occurence…you actually feel like you are accelerating almost. Definitely causes a pucker factor.
It helps to apply your brakes a bit early when riding in the rain to shed any water from the rims and pads…then when you need to apply pressure in earnest, it grips.
And the stock pads on 105 brakes are, at best, marginally OK, so that didn’t help either!!
It’s getting a bit off topic here, of Froome not liking his discs, maybe this should be a different thread?
I was just using the numbers in the Flanders example you gave to show pros don’t make the same equipment choices as you. I’m saying, I can see why they might make that choice. MVDP and WVA wouldn’t ride at 100% of their ability once in the break. At that point they would be riding hard enough to have their gap but it’s not a limiting factor. They are playing tactics and their race craft comes into it. What WVA wouldn’t want to do is use the disc brake Bianchi which risks costing him something tiny, like a second on a decisive climb in case he just misses the move (or another rider behind manages to follow his move).
I’m fully on board with aero and as a breakaway rider it’s something I use regularly. But that doesn’t always mean it’s the best option on every course, even for me. Regarding the original point of this thread, there wasn’t even an aero benefit to going disc brake anyway so it seems a moot point.
I don’t want to delve deeper into this, since this isn’t the topic here, as you pointed out correctly.
I still believe that deeper wheels and aero frames are the best choice in >95% of races/ stages etc.
The margins in aerodynamics are just that much larger than in weight savings.
Just to point out how we got to this topic:
The original point was just because Froome is a massively successful cyclist doesn’t mean his opinion on bike tech is necessarily right and my argument was most pros unbeknownst use slower set ups all the time, just because they are used to them (them being shallow wheels, climbing frames, round handlebars etc.)
That’s where disc brakes win hands down, in the wet there stopping power is excellent.
Well stated.
I can’t comment on mountain bikes as we don’t see a lot in our shop. That said, my MB always seems to have issues… The road bikes we see have tons of issues.
That left me confused, too. Sure, he logs many kilometers, sure, but he has team mechanics, multiple wheelsets with multiple rotors, etc. The only thing which I understand but don’t particularly care about is noise, which seems to be nails-to-chalkboard for many roadies. Ditto for brake squeal. (Perhaps Froome prefers “singing brake tracks” that many carbon rims come with. 
)
Overheating is a weird one. First of all, what about the base line? I’ve heard of cases where people “melted” their rim brake pads on long alpine descents, are disc brakes worse? I doubt it. I haven’t pushed rim brakes that far ever, but having done 1,200+ m of downhill on both, road and mountain bikes, I have never had any problems. The only brake fade was in my fingers 
Peak Torque made a reply, too, where he seems to agree with Froome on most parts. Typically, I agree with him, but this time I am not convinced by his reasoning. He brings up the correct point that the typical energies that need to be converted into heat in one go are significantly higher on the road bike. So far that is entirely correct. However, I think it does not take into account convective cooling, which is much more efficient at higher road bike speeds than mountain bike speeds. If you think in terms of physics, if you go downhill on a road bike, your speed is limited by aerodynamics. So you do not need to convert all of the potential energy (E_pot = m g h) into kinetic energy on a road bike, air resistance will limit your speed. The same is not true on a mountain bike, where in most places you are not limited by air resistance, but the terrain. So much more of the total potential energy needs to be dissipated as heat during braking. Furthermore, you have much worse cooling on a mountain bike since you are going at slower speeds. So his arguments did not convince me.
Where I do agree with Peak Torque is the weight weenie side of things. People should not be riding 140 mm rotors, especially if you are heavier. I think there should be a 180 mm option, especially for heavier riders. Also, GCN did an experiment where they showed that the average stopping distance with 160 mm rotors is shorter than 140 mm rotors. Was that very scientific? No, but I think it points to the fact that with larger rotors, you have a larger lever, and you reach maximum braking force (as dictated by tire traction) faster.
Good points.
Weight Weenie side of things, I think you can get a bike like a Trek Emonda with 160mm shimamo rotors and still be at or marginally below the UCI weight limit. Maybe it’s just what his factor team rolls with?
You can get ~6 kg disc brake bikes with relatively normal parts these days if that is what you want. But frame manufacturers seem to want to use the added weight buffer in different ways (e. g. AFAIK the current top-of-the-line BMC Teammachine weighs a claimed 6.8 kg). At least as far as the pro peloton is concerned, disc brakes effectively do not impact bike weight.
I think fork / frame stiffness around the calliper must play its part here as my disc brakes on my MTB hardly ever rub.
As far as I understand, road bike brake calipers leave less clearance between pads and rotors, so they are also more sensitive than MTB disc brakes.
The issue as I see it is in the set up, disc brakes work very well if set up correctly.
The pad rub issue can be caused by a variety of issues, are the pads/discs brand new? if so there will be next to zero clearance between the pads/disc until either have worn down, accurate caliper alignment with disc also needs to be spot on, if the the surface where the caliper meets the frame is not perfectly flat you are fighting a loosing battle. These pro riders produce so much power which is likely causing plenty of flex through the wheels/frame so its no surprise they are experiencing disk/pad rub.
In regards to the brake fade issue, fit a set of Hope V4’s running vented 203mm discs to a road bike and any problems with brake fade will be gone, but say hello to an extra 2kg+ of weight. My point being is that the lightweight brake components used on top end road bikes are not really suitable for descending mountains.
Maybe the big manufactures need to design a road specific caliper that gives more clearance between disc/pad in order to resolve the issue a lot of users are experiencing? The calipers used at this point in time are basically just MTB calipers.
The point is that by riding an aero bike WVA would have been saving 5-10W all day long when taking his turns, that effort saving means he could either ride at a higher speed for the same power putting the other riders under more pressure or simply save the energy for those moments when he needs everything he has to get over a climb with the decisive move. We’re generally talking about a 1kg difference between an “aero bike” and a “climbing bike” - the numbers show the only way to go is aero.
On an MTB I’ve overheated 180m/160m discs on long decents in the Alp’s a few years ago so I would believe it’s possible on road bikes with their higher speeds and smaller discs. It’s very progressive and gives you plenty of warning.
Making all a rule all rotor’s need to be 180mm would likely solve the issue I guess and level the playing field for all. (but restrict devleopment)
Not to mention economies of scale with MTB, maybe?
A simplistic view of the numbers shows aero always wins. The real world, particularly road racing, is a lot more complex with teammates, tactics, accelerations etc. For the vast majority of a road race a contender is nowhere near their maximal ability. You choose the equipment for the important moment.
All I’m saying is that racers and pros have different reasons for choosing equipment than other people. It doesn’t mean they are necessarily “wrong”.
Whenever an experienced pro is speaking negatively about his equipment it is worth taking note. If they are gushing about how great their equipment is then ignore it.