Why is that sad? I’ve gotten way over 15,000 km out of it, and soon it will time to move on. Newer mountain bikes have much better geometry and ride better. Plus, it is getting harder and harder to get e. g. high-quality tires for it.
Oh, I agree that function / form takes precedent over aesthetics…but the aesthetics are rarely ignored.
Case in point - i ride both mechanical SRAM and Shimano hydro systems. They function well and suit my requirements…but they are still ugly and have me looking at smaller hood systems with envy. 
There is a lot of talk about nothing in this thread.
Rim brakes will still be around.
Disc brakes will be more popular as people upgrade to their next bikes.
You’ll be able to buy either and both with readily be available over the course of the next 5 years.
Both require approximately the same maintenance.
Costs will equalize.
Getting the wheel off and changing tires are not any harder.
The end. 
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Agreed. And the fact that I find Shimano’s hydro levers uncomfortable is just compounded by their ungainliness.
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This point is quoted a few times in the thread, and the MechEng in me has to respond.
Let’s just establish a few facts: one, the limiting factor for brakes on a bike is that the braking moment is limited to the weight of the rider + bike times the moment arm from CG to front wheel contact point. Any braking moment over that limit pitches the rider over the front bars. Second, the first fact above also makes rear brakes completely useless in a max braking scenario, since at the limit, the load on the rear wheel is zero, so the braking force available from the rear is also zero. In theory the same limit applies to a car, but the weight and moment arm being significantly higher, other limits (the static friction coeff times the normal load, namely) come into play way before you can pitch over - in other words, you lock up before you pitch over.
So - the only requirements on a bike brake, to attain max braking effort, are a) that said brake is on the front wheel, b) that it can generate a moment at least equal to the limit described above, and c) that it does so in a controllable fashion, i.e. in a way that allows the rider to modulate up to the limit.
Anyone who has front rim brakes that are not capable of generating the max braking moment described above needs to go back into the shop. You’ve got a much bigger problem than “the wrong brakes”. For everyone else, I think it’s clear that the “harder braking at a later point” is debunked.
This said, all of the above assumes you can generate the limit braking effort - and there are circumstances where disc brakes are way superior to rim brakes in that respect, namely in wet conditions. And there are other advantages of disc brakes (not using a structural part as a wearable braking surface being the primary), and inconvenients as well (requiring the braking moment to be carried by the wheel structure).
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You are missing two important aspects: first of all, rim brakes have much worse modulation and give you no feedback (unlike fully hydraulic disc brakes). That’s not just helpful when the conditions are tricky, but also when you don’t want max braking. Modulation and feedback are what allows you to brake later, not better brake power.
Secondly, I don’t think your representation of max braking is accurate. With proper technique it is much harder to lift your rear while braking. The limiting factor is tire grip, i. e. you want to avoid going from static to sliding friction. For example, you could lock up your rear wheel (modulation) and slide out. Modulation and feedback helps a lot here to avoid that.
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I did mention modulation, although I did not add that disc brakes can offer an advantage there (they do).
As for max braking, contrary to the situation on a car, tire grip is generally largely sufficient to place that limit way above the max braking moment limit - for the front wheel. Your example of a rear wheel slide-out demonstrates again that rear brakes cannot contribute to a max braking effort. The pitching moment generated by braking (regardless of which brake(s) are applied) reduces the load on the rear wheel and brings down its max braking force accordingly.
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You are objectively speaking probably right - what you write makes perfect sense - what I wrote was based on first hand experiences and observations of others.
I ride two bikes, one with rim brakes (Ultegra) and one with disc brakes (Dura Ace). I consistenly find that when I go from rim to disc, I feel more confident in the bike’s braking ability, and when I go from disc to rim, I find myself thinking “God, these brakes are soft”. With disc brakes, my impression is that there is a much more immediate reaction when you start braking than with rim brakes, both in dry conditions and (especially) in rain and wet conditions. Perhaps this can be attributed to modulation and the benefits of hydraulics rather than actual better braking force?
Last year, I did an everesting ride in a short hill here in Oslo (click link), where several dozen riders did 73 repeats with 180 degree turns at the foot of the climb. Almost without fail, I found that those using disc brakes allowed themselves to maintain a higher speed and start braking harder closer to the turning point than those of us with rim brakes, thereby gaining a few seconds’ advantages at each repeat. I also remember Johan Bruyneel arguing on Armstrong’s podcast The Move in July 2019 that Alaphilippe’s superior descending skills can partly be attributed to the advantages of disc brakes. Perhaps this can be attributed to a higher level of confidence in safely dropping faster to a speed that allowed for safe turns, rather than that the brakes actually do brake harder?
Either way, the perceived difference between disc and rim brakes is sufficiently different that I for all practical purposes think discs offer a better braking experience (and hence allows me to ride faster downhill).
Certainly the lever force curve is very different between a mechanical rim brake and a hydraulic disc one, making it less likely that the rider will get close to max effort on the former. The best comparison I can come with is the first-time accounts of anyone who has tried an F1 car - all pre-track training will tell you that you will under-use the brakes, since the pedal is very stiff and the brake force is very high. And every first-timer will under-use the brakes, even if forewarned. This said, someone who is used to either bike braking system can get max performance out of either; jumping from one to the other can be hard however.
I don’t think you are correct, tire grip is a much bigger factor than you make it out to be. Sudden braking maneuvers can unsettle your bike and cause your tires to lose grip, especially when you are putting additional load on your tire by, say, cornering. Because rim brakes are more binary, that will place more limitations on how fast you can go — or at least it requires more skill to take the corner at the same speed. That’s why cars have ABS, you are more capable to steer while braking.
The difference is so obvious when I take some on road downhill segments with my mountain bike rather than my road bike. I have a much better braking performance.
It isn’t just the force curve, it is also feedback. I can feel what my disc brakes are doing, I can feel how hard the my grip. Hydraulics can transmit forces in either direction whereas cable-actuated brakes only permit you to do that one way.
I can propose Chapter 7 of Wilson’s Bicycling Science, third edition. On dry pavement, in average conditions, the pitch-over limit is more than 40% lower than the tire grip limit. You may adjust his calculations to reflect more modern road bike geometries. Note that these are on level ground, in a descent the CG moves closer to the front wheel contact point. Also note that on tandems and some recumbents, the geometry and CG location are quite different and tire grip can be the limiting factor.
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I think I understand the physics (I’m a physicist), and on a flat, dry road you are right. These are relatively easy conditions. I can catapult myself over the handlebars with one finger on my mountain bike.
My point is that on descents with twists and turns doing “max brakes” is not what you want to do. You need to modulate braking according to the grip you have, and the feedback you get from disc brakes is one factor that better allows you to do that. Think of anti-lock brakes: on a dry road surface in a straight line you don’t need them as much. Add steering or snow and ice, and they are a game changer. It’s modulation and feedback, not braking power that is the difference.
If you don’t agree, can you explain why so many riders feel safer and faster on disc brakes? What do disc brakes allow them to do that is harder to do with rim brakes? (This is not a rhetorical question, because I really want to know why I am wrong in case I am wrong.)
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I don’t disagree on the controllability side of things. Better modulation does lead to better braking, allowing the rider to stay closer to the edge (if needed).
This said, the (theoretical) fastest line in a descent is very similar to that of a racing car: brake as late as possible, use max braking effort in a straight line, maintain trail braking only during the turn (to allow turn entry at max speed for the turn radius and no acceleration through the turn), and accelerate out. So max effort use is needed.
And a significant portion of the pro peloton is still on rim brakes. They are not getting blown away in every descent.
In an ideal world without cars and pristine roads, yes. Add dirt on the road from a tractor that pulled onto the road or small debris that made it onto the road. Or car that suddenly pops into view. I am thinking of the most common situations riders find themselves in.
Regarding pros, I reckon it is just a lot easier to get very good on a bike with disc brakes. If you feel more confident, you are more willing to push further. For pros that might or might not matter as much since they have much more training.
Just skimming the content on here but it looks like the argument of generating a significant moment to throw the rider over the bars and 100% front brake loading is not really accurate. Sure in a laboratory test you may find that, but when a rider shifts weight on their rear before initiating full force brakes, you should never see a 100/0% split front/rear. Perhaps it would be 60/40% split, but even that is high; sure if you put CG forward you are going to have a bad time, but I do not agree with the front brake needing to be able to take 100% of the brake force of the entire body. The other question in how fast do you need to brake? Obviously its not the speed that kills you, its the acceleration. I would be very surprised to find ANY front carbon brake wheel capable of stopping a heavy rider ripping at 80km/hr fast without failing, or at least showing significant signs of problems if you slam the brakes for a complete stop. Carbon is just a very poor surface for heat dissipation, its prone to delamination and it decreases braking performance as the thermal values increase. For TT/Triathlon you dont expect to brake and in that case its somewhat acceptable (although there is still risk) but rotors are a much more capable braking system period, and the 100% front wheel brake argument is not exactly valid unless you ride like an idiot or are made of cardboard.
Edit: it is worth noting that you may argue that failure of the brake track for 1 complete full stop from an extremely high speed is actually a feature. Look at the tests for one of the wheel manufacturers that showed their brake tracks not failing at high speeds when brakes are applied; the brake track basically became useless due to the pad/carbon glazing and as a result, you see the wheels never fail under load… because they are generating low amounts of heat… because the coefficient of friction is so poor and you are going full speed. Failure of the brake track for a safe complete stop technically means the wheels worked to stop the rider. Something to consider, as if you evaluate a wheel for “structural survivability” alone, I can guarantee that you will stop… just not likely how you want to.
Shifting the COM back increases the moment arm, but does not do magic to the max braking moment. As long as total weight times the friction coeff times vertical COM location above the front wheel contact point is higher than total weight times the longitudinal COM location behind the front wheel contact point, the limit will be set by pitching over rather than the front wheel skidding out.
In the example from Wilson, he places the COM 45 inches above the ground and 25 inches behind the front wheel contact point. This gives a max braking deceleration of 0.56g, going over that pitches the rider over. With a friction coeff of 0.8, the max deceleration possible would be 0.8g, if pitching over was not an issue. You can take his calculations and adjust them to any geometry you want to.
There’s a pretty good reason why motorcycles can’t brake as fast as cars: A GP bike can generate approx 1.8g decel, vs… 5.7g for an F1. Same problem.
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I’m arguing that worrying about an event of rear wheel contact failure is not a primary concern. You are correct, in a max braking scenario then yes technically your front wheel will take 100%, but that is beyond the scope of expected use cases. You are talking about successful lifting of the rear tire and somehow stopping successfully; if the rear wheel lifts, you are in for a bad time anyways. With that being said, I would never suspect you could achieve full lift of the rear wheel with rim brakes. And with proper brake behaviour you should never see it entirely. But you are correct, if you were trying to stop an 80km/hr rider basically instantly, I would also expect you to see some exciting acrobatics
Edit: and that’s assuming 0 slipping between tire and road interface. I would suspect you would see slip occur before you would see this actually happen.
Not really - I’m saying that assuming the friction limit is not reached first, no vehicule can brake at a higher moment than its weight times COM longitudinal location. Since on a road bike this max moment comes way before the friction limit on a dry road, it is essentially what drives the brake requirements. Generating more braking force has no practical use. And any well-tuned front brake, disc or rim, must be able to get to that limit.