Hydraulic Vs mechanical brakes
02-10-23, 06:12 AM
#226
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So a very clear result in the video. No question hydraulic disc brakes have better performance on technical alpine descents and even more so if it's wet. The only slight surprise to me in that video was the significantly shorter stopping distance on the disc brakes in both dry and wet conditions - which strongly implies that rim brakes are actually power limited at high speed (he was stopping from 53 kph) and not capable of reaching the limit of tyre grip at those speeds even in the wet. Thinking back to my own fading experience of wet braking on fast descents I do recall rim brakes feeling woefully under-powered and slow to respond.
As there is no mention of lack of modulation in the video, I presume that comment was from your personal experience. Maybe your brakes have some issue (bleeding, pad contamination?), since accurate and consistent modulation is one of the primary advantages of hydraulic brakes. I've been using hydraulic disc brakes since 2004 in mtb and since 2019 on road bikes. Modulation has always been a strong point. Perhaps I've been lucky, but I really haven't had any major issues with disc brakes over 19 years of use on many different bikes. Only my mtb brakes have required the odd bleed.
As there is no mention of lack of modulation in the video, I presume that comment was from your personal experience. Maybe your brakes have some issue (bleeding, pad contamination?), since accurate and consistent modulation is one of the primary advantages of hydraulic brakes. I've been using hydraulic disc brakes since 2004 in mtb and since 2019 on road bikes. Modulation has always been a strong point. Perhaps I've been lucky, but I really haven't had any major issues with disc brakes over 19 years of use on many different bikes. Only my mtb brakes have required the odd bleed.
Why so much faster to stop? 1) 55 km/h is about 15 m/sec. 2) Rim brakes lack the immediacy of hydraulic disc brakes. 3) There is also a transient delay to heat the rim whereas a disc immediate.
The difference is like comparing analog to digital. On/Off light switch to a dimmer. They both get you to full brightness, one just takes a bit longer ( some hundreds of millisecond)
The range of hand force required is higher with rim brake and the braking force is lower, so the sensitivity is higher. Thus, easier to modulate. I don't care what idiotic blogs and articles say.
https://www.sheldonbrown.com/disc-brakes.html
02-10-23, 06:13 AM
#227
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Why? Because:-
a) You are weighing up the pros and cons of buying a bike with disc brakes?
or
b) Because you are hoping they won't have any adjustment, so you can further prove to yourself that rim brakes are the best choice?
I know the answer, but you will be disappointed.
a) You are weighing up the pros and cons of buying a bike with disc brakes?
or
b) Because you are hoping they won't have any adjustment, so you can further prove to yourself that rim brakes are the best choice?
I know the answer, but you will be disappointed.
02-10-23, 06:25 AM
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The very first time I rode my new HRD disc braked bike on a STRAVA segment that I have ridden a million times, I set a PB. It has several technical descents that you enter at high speed. I doubt that bike is any faster and I know my power was not any better, it is the brakes. They are vastly superior at high speed (40mph+) than any rim braked bike I have ridden
02-10-23, 06:32 AM
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I presume you know those particular brakes have a bite point adjuster under the hoods? If you are finding the initial bite too aggressive, try backing off on the adjuster. Note that there is also a second adjuster for lever position/reach - which is independent of bite point.
If I move brake lever A 25 mm and generate 2x clamping force and Brake lever B moved 50 mm generates x clamping force, the sensitivity of lever B is 4 times greater than A.
Initial bite is irrelevant to the point being made.
The range of motion of the disc caliper is very small compared to a rim brake as are the range of motion of the levers themselves. This is what causes me to feel a lack of modulation, it takes very little movement on the disc brake lever to generate a lot of force. I only have 1200 miles on them, so, I am still learning but it is not comfortable yet
02-10-23, 06:35 AM
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Bite point is merely an offset, it has no effect on the lever throw/clamping force relationship.
02-10-23, 06:40 AM
#231
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Even Sheldon Brown's site says disc brakes can be grabby.
Why so much faster to stop? 1) 55 km/h is about 15 m/sec. 2) Rim brakes lack the immediacy of hydraulic disc brakes. 3) There is also a transient delay to heat the rim whereas a disc immediate.
The difference is like comparing analog to digital. On/Off light switch to a dimmer. They both get you to full brightness, one just takes a bit longer ( some hundreds of millisecond)
The range of hand force required is higher with rim brake and the braking force is lower, so the sensitivity is higher. Thus, easier to modulate. I don't care what idiotic blogs and articles say.
https://www.sheldonbrown.com/disc-brakes.html
Why so much faster to stop? 1) 55 km/h is about 15 m/sec. 2) Rim brakes lack the immediacy of hydraulic disc brakes. 3) There is also a transient delay to heat the rim whereas a disc immediate.
The difference is like comparing analog to digital. On/Off light switch to a dimmer. They both get you to full brightness, one just takes a bit longer ( some hundreds of millisecond)
The range of hand force required is higher with rim brake and the braking force is lower, so the sensitivity is higher. Thus, easier to modulate. I don't care what idiotic blogs and articles say.
https://www.sheldonbrown.com/disc-brakes.html
Your thoughts on brake modulation are interesting. So you have equated higher hand force = easier modulation. But modulation really comes down to lever travel (resolution) and the consistency of the brake force response in relation to lever travel. Weighting of the lever is a personal preference and you could argue that they are set up too light, but that's just how most people prefer them.
I come from an mtb background so I'm used to 1 finger braking with decent modulation. You just have to learn not to grab the brakes too hard initially, which is unfortunately what rim brakes teach you to do!
02-10-23, 06:48 AM
#232
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According to some people, only hydraulic disc brakes have enough stopping power for any type of serious riding....Anything that's cable actuated has mediocre stopping power, is too complex to set up and adjust, requires frequent cable and housing replacement and should only be used on cheap department store bikes.
02-10-23, 06:56 AM
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I assume you did not read what I wrote WRT sensitivity.
If I move brake lever A 25 mm and generate 2x clamping force and Brake lever B moved 50 mm generates x clamping force, the sensitivity of lever B is 4 times greater than A.
Initial bite is irrelevant to the point being made.
The range of motion of the disc caliper is very small compared to a rim brake as are the range of motion of the levers themselves. This is what causes me to feel a lack of modulation, it takes very little movement on the disc brake lever to generate a lot of force. I only have 1200 miles on them, so, I am still learning but it is not comfortable yet
If I move brake lever A 25 mm and generate 2x clamping force and Brake lever B moved 50 mm generates x clamping force, the sensitivity of lever B is 4 times greater than A.
Initial bite is irrelevant to the point being made.
The range of motion of the disc caliper is very small compared to a rim brake as are the range of motion of the levers themselves. This is what causes me to feel a lack of modulation, it takes very little movement on the disc brake lever to generate a lot of force. I only have 1200 miles on them, so, I am still learning but it is not comfortable yet
I know you think the bite point is irrelevant, but you will find in practice that it helps a little if you are finding the brakes too grabby. Have you actually tried adjusting it? Think about the bite point with rim brakes, which you have been using for all these years. How much does the brake lever move before your brake blocks touch the rims? Is it more or less "dead" travel than what you have now on your disc brakes?
Last edited by PeteHski; 02-10-23 at 07:06 AM.
02-10-23, 07:10 AM
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According to some people, only hydraulic disc brakes have enough stopping power for any type of serious riding....Anything that's cable actuated has mediocre stopping power, is too complex to set up and adjust, requires frequent cable and housing replacement and should only be used on cheap department store bikes.
02-10-23, 07:24 AM
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The range of motion of the disc caliper is very small compared to a rim brake as are the range of motion of the levers themselves. This is what causes me to feel a lack of modulation, it takes very little movement on the disc brake lever to generate a lot of force.
02-10-23, 07:24 AM
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The range of lever travel on rim brakes does vary from Mfg to Mfg, but they are noticeably longer than on my HRD brakes. And, they offer less clamping force. So the force/mm of travel is much higher on my hydraulic disc brakes and that makes modulation more sensitive at least to my hands. The point isn't the delay until the pad hits the rim or rotor, rather, it is the smaller amount of lever pull needed to generate more force than with a rim brake. Thus, feathering the brakes for a corner is trickier. I do have peripheral neuropathy in my hands, so, I could be more sensitive to this difference in brake behavior. I do have to move the lever one click inwards and will play around also with the lower biter screw. I have been preoccupied for 2 months trying to get them to stop squealing and think I finally resolved it.
I think there was a mechanic in this thread making a similar comment.
I think there was a mechanic in this thread making a similar comment.
02-10-23, 07:31 AM
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02-10-23, 08:11 AM
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Pete, don't sell yourself short! You could never disappoint me!
02-10-23, 08:18 AM
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My brake levers probably move 1/4" before the shoes contact the rim. One finger braking is easy and often all I need.
02-10-23, 08:21 AM
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Pete, I've talked about this. Please keep up: My brakes work fine--probably better than some disc brakes. I have no desire to ever get a bike with disc brakes. I certainly would never add them to my current bike--simply no good reason, unless I wanted to make my bike heavier or uglier. If I ever do get another bike, it'll probably be some sort of a hybrid, and I won't have a choice as to what brakes it comes with. When I have to bleed my brakes the first time, I'll be in touch.
02-10-23, 08:31 AM
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You tell me to zip up and yet here you are on a thread specifically discussing mechanical vs hydraulic DISC brakes telling us that you have zero intention to ever get a bike with disc brakes. So what's your point other than trying to convince yourself that they are not worthy?
02-10-23, 08:36 AM
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Why wouldn't I like them? Unless they're a PITA to work on or squeak incessantly. If none of that, and they stop fine, I'll be good.
02-10-23, 08:37 AM
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Yeah right. My "confirmation bias" is based on actually preferring disc brakes first hand, not imagining how they might compare. If by now I had had a bad experience with disc brakes I would be agreeing with you about how great rim brakes are and would certainly not be riding a road bike with disc brakes.
You tell me to zip up and yet here you are on a thread specifically discussing mechanical vs hydraulic DISC brakes telling us that you have zero intention to ever get a bike with disc brakes. So what's your point other than trying to convince yourself that they are not worthy?
You tell me to zip up and yet here you are on a thread specifically discussing mechanical vs hydraulic DISC brakes telling us that you have zero intention to ever get a bike with disc brakes. So what's your point other than trying to convince yourself that they are not worthy?
02-10-23, 08:39 AM
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02-10-23, 08:44 AM
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02-10-23, 09:05 AM
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I have no idea. Whatever hydraulic discs came on a 2021 Giant Talon.
02-10-23, 09:51 AM
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Just because one a brake lever moves farther for a given increase in braking force does not mean it is easier to control.
Also, just because one brake needs more force at the lever for a given increase in braking force does not mean it is easier to control.
Anyone who has spent time on high quality hydros will know this.
More ”Sensitive” to input does not necessarily mean less control.
Also, just because one brake needs more force at the lever for a given increase in braking force does not mean it is easier to control.
Anyone who has spent time on high quality hydros will know this.
More ”Sensitive” to input does not necessarily mean less control.
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02-10-23, 09:52 AM
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I rode bikes like yours in the 80s and early 90s extensively, so I've got a reasonable idea how effective they are. My last rim-brake road bike was from the late 90s with Shimano Ultegra brakes of that era. I don't remember them being any better or worse than those of the 80s. Adequate, but not something I would want to be using today out of choice.
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02-10-23, 09:56 AM
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As has been mentioned----this thread is about the choice between cable and hydro discs.
Everyone like different things.
A lot of people like to denigrate people who are different. Just like the rest of the world, BF is full of humans and a lot of humans feel a need to knock down as many people as possible to climb on top ... even if they are not actually knocking anyone but themselves, and descending into personal cesspools, why crowing about their victories.
Ride bikes. If you ride Fixie or Kamikaze, you don't need brakes. if you have brakes, cool.
Go somewhere and do something good. Be someone good.
Everyone like different things.
A lot of people like to denigrate people who are different. Just like the rest of the world, BF is full of humans and a lot of humans feel a need to knock down as many people as possible to climb on top ... even if they are not actually knocking anyone but themselves, and descending into personal cesspools, why crowing about their victories.
Ride bikes. If you ride Fixie or Kamikaze, you don't need brakes. if you have brakes, cool.
Go somewhere and do something good. Be someone good.
02-10-23, 09:56 AM
#250
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I rode bikes like yours in the 80s and early 90s extensively, so I've got a reasonable idea how effective they are. My last rim-brake road bike was from the late 90s with Shimano Ultegra brakes of that era. I don't remember them being any better or worse than those of the 80s. Adequate, but not something I would want to be using today out of choice.
I agree that brakes in the '80s, even Dura Ace single pivots, were no great shakes. However, today I'm using Dura Ace dual-pivots with compressionless housing. You really don't have any idea how effective my brakes are.
