Originally Posted by
smashndash
I can’t tell if you believe these things or if you’re pointing out the excuses people make to defend the things they believe in.
The performance difference between rim and disc brakes is disc’s ability to cut through water and stop in the wet. The “power” and “modulation” are better with hydraulic rim brakes. Most people haven’t even tried compressionless cable housing with their rim brakes. Hydraulic rim brakes are incredibly rare, but there have been a few and those are supposedly better than disc brakes. You could argue that disc brakes have an advantage because the pads sit closer to the rotor, but that causes a lot of rubbing issues. If rubbing were acceptable, you could do the same with rim brakes. Rim brake pads also compress a bit more but you can remedy that by using thinner or harder pads if it really bothers you.
I personally think that the main reason disc brakes came in was because carbon rim brake clinchers were really tough to get right, especially in the rain and long descents. That and maybe wider tires became fashionable and nobody wants 90s era V brakes on their road bike. More cynically, perhaps, bike manufacturers ran out of supposed “innovation” to push on us.
I truly sympathize with the co-op mechanic above. It must be tough, especially with so many people believing that disc brakes are the second coming. I know that, for most people, hydro discs are pain-free, but it also seems that there’s greater scope for things to go wrong. At the very least, it seems harder to get them “perfect”. On a group ride last week, two people had new Specialized disc brake bikes and both were rubbing HARD on steep kickers. Both of my friends on my team who upgraded to road disc last season rub on hill sprints. I’m not even OK with my bike making vague clicking sounds. If that happened to my bike (I sprint up hills frequently), I would demand a refund or warranty.
I first saw disc brakes on a Japanese home market 3speed in 1973. Shimano. Next up was the Phil brake. Disc has been a long term project. Lots of engineering work has been done. Ten years ago the marketing push was huge while the brakes were still plain bad. Five years ago the true believers were proclaiming the second coming and the brakes were sometimes usable. In the meantime carbon rims and dual pivot rim brakes were causing havoc. The rim wear problem is far worse with dual pivot and the industry was not going backwards on that. Carbon rims were so easy to sell and hugely profitable.
Discs still have abundant problems, as you note in your post. Except if you believe the marketing, in which case they have gone beyond perfection. Engineering work and trial and error work continues to be done, and is done with a will. Basically nothing has been done with rim brakes. Unless you count Shimano Direct Mount, which is just digging a deeper hole. Even limiting the investigation to extant brakes it is evident that some rim brakes are much better than others at their ability to cut through water and stop in the wet. They are not all the same. No one is investigating why. Even very simple stuff like braze-on centerpulls is a miniature niche for the Jan Heine crowd. Peugeot did that for a couple seasons with the PY-10CP and any lucky enough to have ridden one knew how well it worked in the wet. But I'd be surprised if there were more than a couple hundred of those and it might have been less. Any lucky enough to ride Campy Record OR knew how well it worked in the wet and again there were likely only a few hundred sets. Half of which are still in the box with Campy collectors. Marketing trumps engineering every time.