I’m not sure there are many more testing environments. Descending Hardknott is one of the very few things that’s worse than climbing it, and one of the few truly memorable experiences on a bike that I have no desire ever to repeat.
Honestly, I find changing brake pads more simple and quicker on a disc brake bike than on a rim brake one.
Also I find that there’s less routine maintenance with hydro disc brakes, it’s very fit and forget.
I’ve bled Shimano brakes and it’s pretty straight forward, it takes about 20 mins. However, I find that you barely ever need to bleed the brakes. I had to change brake cables more often than I bleed my brakes.
I’ve never bled SRAM brakes myself and more wary of them due to the use of toxic DOT fluid which seems a silly decision by SRAM to me.
I agree that decent alloy rims and good quality brake blocks like Koolstop Salmon’s give a great braking performance. However, it can’t be denied that carbon rims and rim brakes was always a bit of a bodge.
Well, I don’t have to ride on carbon wheels, I want to because, well, they’re better in every way (if you have discs, of course).
The alloy wheels work, of course, as do rim brakes, but… well. Meh. I’m not going to buy them.
A disc brake bike with carbon wheels will weigh more than a rim brake and aluminum wheels one.
So you won’t buy the carbon wheels for the weight advantage…
What are the advantages then? Aero? At amateurs speeds? I’m very doubtful of how effectively an advantage are carbon wheels (clincher) for an amateur…
Yes, aero wheels make a measureable difference even at amateur power output. In triathlon or otherwise when riding solo where you’re catching the wind, aero wheels net you slightly north of 1% over a modern pair of alloy wheels. In contrast, two hundred grams more make a difference of 0,2% up a proper climb and none on the flat. The same consideration applies to aero bike frames which are also slightly heavier, but the advantages are also worth it outside of mountain climbs.
This is well understood by, for instance, most everyone who does triathlon. Good position, well fitted trisuit or road suit, aero wheels, aero bike, and you can go pretty quickly on the flat, even on just 200W, which is the sort of power many amateurs can and do sustain for hours on end.
Branko identifies that weight on a bike is worth carrying if it contributes to speed. Every single second riding aero frames and wheels on flat / downhill, they are a welcome presence adding speed. Similarly derailleur gears, a weight worth carrying for ideal cadence / speed every single second of a ride. Returning to topic, disk brakes are a weight on a bike that bring speed benefit only for a handful of seconds, in extreme rider descending use models, weather conditions, and terrain. The rest of the time, the vast majority of the time, and for non-world tour riders all of the time, they are dead weight. A disk brake on carbon rims does enable later application on descents, but when your fingers are already on the levers, so what.
I think a lot of this discussion seems to relate only to pure speed. I’d say that pure speed is pretty secondary to most riders.
Think about it: >98% of all riders never race, and never will. Does 40 seconds in a 2 hour ride matter? More to the point, the vast majority of riders have an FTP below 3.5w/kg. If they want to get faster, more time spent training, as well as spending money on coaching, power meters, and better food will yield far greater results than any wheels/frames/brakes they can buy.
What most riders do need, though, is comfort, reliability, safety, value for money, and ease of maintenance: these are all things that should be factored into any equipment decision as well as speed.
To take myself as an example: I’ll be spending a fair chunk of money early next year on a new bike. It will have a steel frame, a mechanical groupset, and rim brakes. I am very aware that it will not be as fast as a carbon aero bike that I could get for the same money. But it will me (in my opinion, others are very free to disagree) more reliable, more durable, better looking, easier to maintain, and fast enough for my riding, which will be 75% solo rides and 25% club runs, with the odd sportive.
And fast enough is important. I haven’t pinned on a number in 7 or 8 years now, and don’t plan to again. I’m still in fairly decent shape (just over 4w/kg) and can just about hang with the A group on the weekend run. I can’t hang on the Wednesday night ‘bullet train’ chain gang. Now maybe a top notch carbon race bike would let me just about hang in there, but it’s a bit fruitless. I’m 40, can’t regularly spare much more than 10-11 hours a week to train, and I know can’t compete with 21 year olds who don’t have busy jobs, kids, and can spend more than 15 hours a week on a bike and prioritising recovery. More to the point, I ultimately don’t derive most of my cycling pleasure from measurements against a stop watch or competition. So why spend the money there?
So - and I know this is getting longwinded - I’ve chosen a bike which suits me and my skills/fitness, and what I want from it. All equipment decisions should be looked at through that lens, and disc vs rim brakes are no different.
Interesting. Virtually all the riders I ride with at least occasionally race, albeit mostly triathlon, and most are in the 35-45 age bracket, like me, where training time comes at a premium and recovery time is what happens when you’re done with everything which needs doing. Even the ones who aren’t very fast are still trying to better their own times, if they can, though. Even those who are under and will realistically always stay under 3.5W/kg.
So the idea of getting a bit of extra speed from equipment choice is attractive to them and to me even if it only “matters” 1% of the time we are actually racing. I mean… matters - maybe it’s not the right word, none of us live from it, but if much of your free time as a time-strained middle aged adult goes into triathlon, buying the odd new toy which improves performance or anything else, if you can, is motivating in a way.
When they buy new bikes, they are buying discs, though, for the pure all weather braking performance - at the end of the day improved all weather braking from hydraulic discs gives them more confidence.
I can understand the allure of a retro steel road bike with rim brakes; I’ve looked at some lovely vintage looking high end steel framesets, myself. At the end of the day I just couldn’t bring myself to spend a good chunk of money on what would be used as a fair weather bike and which is worse than my carbon one, but they can be really pretty.
If someone races, then I think the priorities change - that’s totally fair.
Interestingly, my wife is a triathlete. She’s thinking about a new bike, but is hesitant. Part of that is she is committed to discs and electronic shifting, which will push the cost up. Both of those things I think are sensible for her use case; she’s neither a great bike handler nor a confident descender (running background, didn’t cycle at all between her early teens and late 20s), and the ability to shift from the base bars will help her in particular but is generally an advantage in TTs.
If I were buying a similar bike, I’d also go for electronic but would probably go with rim brakes. If I was going back into road racing, I think I’d be really torn on both gearing and braking systems. If I were buying a crit bike, I’d buy what I could afford to write off!
I have a bit of a bee in my bonnet that most higher end road bikes are watered down race bikes which are then sold to people who don’t race and for which they’re a poor fit, in all senses of the phrase. It’s one of the reasons IMO for the rise of gravel bikes: people get on them and actually feel comfortable and confident on a bike! But that aside, what I’ve been trying to illustrate is the dogmatic position that ‘X is better than Y’ (without any caveats) is nearly always wrong.
A partially off topic consideration… The “A group” and the “bullet train group” seem to be a common thing everywhere in the world!
Here in Italy, in the city where I live, we also have these spontaneous groups, we just call them differently… "Formula 1“!!!