Hello Froze,
I am not sure if I asked you this question before in the forum or not. my apologies if you already answered it. Rim vs Disc, which one you prefer? for somebody like myself investing in the new road bike which one do you recommend? Thank you
Let me tell you what a friend and I did.
My friend bought a brand new Trek with hydraulic disk brakes about 5 years ago, I had bought a new bike in 2013 but it had rim brakes, his and my bike came with aluminum wheels, so I proposed a test for us which he agreed to do. the first test would be 3 runs at 15 mph then we would take turns saying stop and hit the brakes hard, then another set at 20, and a final set at 25. With us and the weight of our bikes we were within 3 pounds, I was a tad on the heavier side because my bike was 2 pounds heavier. He had 25mm Conti 4000s (I recall the exact model of 4000's) and I had 23 on the front and 25 on the rear Vittoria Rubino pros. We used the exact same PSI. The only rule was we had to stay in the seat and not slide our butts toward the rear to help with rear braking. So off we go, the 15 and the 20 mph runs we stopped within a foot of each other, sometimes I was a bit shorter and sometimes he was, we attributed that to reaction time differences; but the third set at 25 something odd happened, the first stop I stopped about a foot shorter, no big deal, the second stop I stopped about 2 feet shorter, and the third stop I stopped over 3 feet shorter!? why? The only thing we could think of was brake fade, so he touched his front rotor and singed his finger, then he touched my rim and though hot it didn't burn the top skin, so from that we knew it was brake fade.
Now having said that, there are some conditions, in the rain disk brakes will stop sooner because the rotor is smaller than the rim so the it doesn't take as long to wipe the water off. If you have very expensive rims the disk will make the rims last a lot longer, but if your rims are just the common $400 a piece the cost between replacing the expensive rotors and pads will break even with replacing the rim. Also if you have carbon fiber rims, it's extremely important that you use disk brakes.
Now 2 months ago I bought a new touring bike after crashing my old vintage bike, the new touring bike came with mechanical disk brakes, the old one had cantilever brakes, I can't test both bikes loaded obviously so all I can report is what I remember. The old brakes did take more hand pressure to stop with, especially if I needed to stop fast when loaded, the new disk brakes the lever action is a lot smoother requiring less muscle on my part to activate. Do the disk brakes stop better? ehh, I don't really get a sense that they do, it seems like they do because less effort is required to get the brakes to work, but if I could do a test like I did above it could be that under panic stopping they could both stop darn near the same. I think when people operate disk brakes for the first time, especially hydraulic, they get the idea that they will stop faster because the of less effort required, but it's their brain deceiving them.
What stops a bike is the brake pad friction combined with tire traction on the pavement, once you lock up your tires it doesn't matter what braking system you use, at that point of lock up or near lock up it's all about the tires traction ability on pavement, it's not about disk vs rim brakes.
I've raced and ridden on rim brakes for over 40 years, I see no problems with the rim brakes whatsoever, and if you go to any Tour De France history of races you won't find mass graves at the end of corners from going down a fast descent where riders couldn't stop and flew right over a cliff, they still hit the same speeds of 60 to over 70 mph with rim brakes back then as they do with disk brakes today. They also raced in the rain with rim brakes with the same results, no mass graves at the end of fast turns; they lose traction in the rain the same way they did 40 years ago, the tires can't grip the wet pavement and they slide out and crash, they don't crash due to using rim brakes vs disk brakes.
Anyway, it's my opinion based on my experiences, I didn't say all of that to get into a war with disk lovers. I do like my disk brakes on my touring bike though, the mechanical disk feel more like very good rim brakes so it's easier to modulate the brakes vs the hydraulic braking system I test rode, I didn't care for the hydraulic brakes, others will disagree but that's fine.