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Re: A disc brake primer - part 1 [Herbert]
[ In reply to ]
Dang it, Herbert - you're going to get 'em all riled up! Hasn't there been enough disc brake debate going on in here lately?! ;)
Re: A disc brake primer - part 1 [gregk]
[ In reply to ]
This was an excellent article, Greg.
Re: A disc brake primer - part 1 [vjohn]
[ In reply to ]
vjohn wrote:
This was an excellent article, Greg.Thanks! The attempt was to get beginner-intermediate folks up to speed on some of the basics that they likely wouldn't otherwise foresee or understand. It was originally going to be one article, but as is often the case, once I really dive in to writing it starts changing and I always think of new things (or different ways to word existing things). Not to mention there are so many competing priorities - article length, type and number of images, other content on the site, etc.
Re: A disc brake primer - part 1 [vjohn]
[ In reply to ]
vjohn wrote:
This was an excellent article, Greg.Agreed. Especially with this part:
"The thing I think we all need to get out of our heads right now is that ALL disc brakes perform better than ALL rim brakes (or vice versa). It’s just not the case. If someone is emphatically making that point to you, I suggest running away or otherwise not wasting your time. There are a TON of factors that influence brake performance, such as rim material, pad material, installation/setup, method of actuation (cable or hydraulic), rotor size, and even frame/fork stiffness. If you want to read more, this thread in our reader forum covers the topic – including a test done by Tour Magazine which concluded that hydraulic disc brakes only resulted in 2-3% shorter stopping distances than standard cable rim brakes."
One nit I'd pick though is in point #7. Changing out rim brake pads for ones that perform better in adverse conditions doesn't need to be an ongoing thing. Most of these pads (such as KoolStop Salmon, or Swiss Stop BXP) perform better than standard black pads in dry conditions as well. No need to change them out besides once.
Also, since the fluid in hydraulically actuated rim brakes doesn't heat up, IME there's less need for bleeding due to possible moisture absorption. In disc systems that moisture can lead to water vapor bubbles when heated. That heat just doesn't happen in rim brake hydraulic applications.
http://bikeblather.blogspot.com/
Re: A disc brake primer - part 1 [gregk]
[ In reply to ]
As someone who has been riding and working on bikes for >30 years, but using disc brakes (on 1 out of 5 bikes) only for the last 2 years, a lot of it resonated with me. People seem to be of the impression these things are simple, easy to use "plug & play" components, and they're not.
Re: A disc brake primer - part 1 [Herbert]
[ In reply to ]
Perfect timing! I just picked up my new 'cross bike yesterday, and it came with Shimano hydraulic disc brakes, my first foray into the disc brake world. Great article, thanks for posting!
___________________________________________________
Taco cat spelled backwards is....taco cat.
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Taco cat spelled backwards is....taco cat.
Re: A disc brake primer - part 1 [Tom A.]
[ In reply to ]
Tom A. wrote:
vjohn wrote:
This was an excellent article, Greg.Agreed. Especially with this part:
"The thing I think we all need to get out of our heads right now is that ALL disc brakes perform better than ALL rim brakes (or vice versa). It’s just not the case. If someone is emphatically making that point to you, I suggest running away or otherwise not wasting your time. There are a TON of factors that influence brake performance, such as rim material, pad material, installation/setup, method of actuation (cable or hydraulic), rotor size, and even frame/fork stiffness. If you want to read more, this thread in our reader forum covers the topic – including a test done by Tour Magazine which concluded that hydraulic disc brakes only resulted in 2-3% shorter stopping distances than standard cable rim brakes."
One nit I'd pick though is in point #7. Changing out rim brake pads for ones that perform better in adverse conditions doesn't need to be an ongoing thing. Most of these pads (such as KoolStop Salmon, or Swiss Stop BXP) perform better than standard black pads in dry conditions as well. No need to change them out besides once.
Also, since the fluid in hydraulically actuated rim brakes doesn't heat up, IME there's less need for bleeding due to possible moisture absorption. In disc systems that moisture can lead to water vapor bubbles when heated. That heat just doesn't happen in rim brake hydraulic applications.
Regarding #7, I agree that you can normally get away with running something like a KoolStop salmon year-round. But, when I moved to Florida I found them to be almost *too* grabby because it's so hot and humid here. They just felt kind of strange, and like they weren't modulating well. I switched back to their all-black "dry" compound, and it felt a lot better. It was unexpected, because I had used the salmons or dual compounds pretty much exclusively when I was up in Michigan.
And yes, you are right about the hydro rim brakes. I thought about that, but at some point I have to draw a line in terms of word count and detail (or at least I try to, when writing for the ST home page, where the average reader tends to be less techy than the forum folks).
Re: A disc brake primer - part 1 [gregk]
[ In reply to ]
I wonder if there are any stats on what percentage of bike accidents over the past 10 years would have been avoided or lessened if disc brakes were on the bike instead of rim brakes
Re: A disc brake primer - part 1 [spot]
[ In reply to ]
spot wrote:
Perfect timing! I just picked up my new 'cross bike yesterday, and it came with Shimano hydraulic disc brakes, my first foray into the disc brake world. Great article, thanks for posting!Thanks! Lucky for you, the Shimano hydros are about as good as it gets (as of today) in terms of being trouble free. I like their resin pads (low-ish noise), and if you have them set up by a good mechanic, keep the rotors clean, and don't switch wheels a bunch, you should be okay. More details to come in article part 2...
Re: A disc brake primer - part 1 [RBR]
[ In reply to ]
RBR wrote:
I wonder if there are any stats on what percentage of bike accidents over the past 10 years would have been avoided or lessened if disc brakes were on the bike instead of rim brakesI doubt it. And even if there was, there's no chance that it would capture enough detail to be meaningful (because there's so much variability in all of the different rim and disc brakes - mechanical/hydro, rotor sizes, pad materials, rim materials, maintenance and care, weather/terrain, riding style, rider weight, etc). I've seen failures from rim brakes, and failures from disc brakes - https://bikerumor.com/...-but-will-they-work/
If I had to really generalize, I think the overall safest / most-idiot-proof setup is a standard rim brake (i.e. Ultegra), a good pad, and an alloy rim. I'm a little worried about disc brakes showing up en masse, and people not checking the pad wear (they wear out quite a bit quicker than rim brake pads)... and I've seen some rim brake bikes with dangerously thin rim pads. As in - they never get checked or replaced. On a disc brake bike, you'd be all the way to the backing plates by then.
Re: A disc brake primer - part 1 [gregk]
[ In reply to ]
gregk wrote:
Tom A. wrote:
vjohn wrote:
This was an excellent article, Greg.Agreed. Especially with this part:
"The thing I think we all need to get out of our heads right now is that ALL disc brakes perform better than ALL rim brakes (or vice versa). It’s just not the case. If someone is emphatically making that point to you, I suggest running away or otherwise not wasting your time. There are a TON of factors that influence brake performance, such as rim material, pad material, installation/setup, method of actuation (cable or hydraulic), rotor size, and even frame/fork stiffness. If you want to read more, this thread in our reader forum covers the topic – including a test done by Tour Magazine which concluded that hydraulic disc brakes only resulted in 2-3% shorter stopping distances than standard cable rim brakes."
One nit I'd pick though is in point #7. Changing out rim brake pads for ones that perform better in adverse conditions doesn't need to be an ongoing thing. Most of these pads (such as KoolStop Salmon, or Swiss Stop BXP) perform better than standard black pads in dry conditions as well. No need to change them out besides once.
Also, since the fluid in hydraulically actuated rim brakes doesn't heat up, IME there's less need for bleeding due to possible moisture absorption. In disc systems that moisture can lead to water vapor bubbles when heated. That heat just doesn't happen in rim brake hydraulic applications.
Regarding #7, I agree that you can normally get away with running something like a KoolStop salmon year-round. But, when I moved to Florida I found them to be almost *too* grabby because it's so hot and humid here. They just felt kind of strange, and like they weren't modulating well. I switched back to their all-black "dry" compound, and it felt a lot better. It was unexpected, because I had used the salmons or dual compounds pretty much exclusively when I was up in Michigan.
Yeah...the 1st gen DA dual pivots and "aero" brake levers on my '86 Bianchi have such a light lever feel and leverage that I had to "detune" them from using straight up Salmons to the dual compound pads. But, I consider that a good problem to have :-)
gregk wrote:
And yes, you are right about the hydro rim brakes. I thought about that, but at some point I have to draw a line in terms of word count and detail (or at least I try to, when writing for the ST home page, where the average reader tends to be less techy than the forum folks).Understood. Then again it also points out an advantage of hydro in a rim application over a disc application...along with there not being a need for a fluid reservoir, and thus less room needed in the levers. For example, look at the Magura TT levers (or the Rotor Uno road lever) and their master cylinder vs. what's in a SRAM or Shimano road lever.
http://bikeblather.blogspot.com/
Re: A disc brake primer - part 1 [Herbert]
[ In reply to ]
Well, that makes me feel better about buying new rim-brake bikes this year, so thanks for that!
The point is, ladies and gentleman, that speed, for lack of a better word, is good. Speed is right, Speed works. Speed clarifies, cuts through, and captures the essence of the evolutionary spirit.
The point is, ladies and gentleman, that speed, for lack of a better word, is good. Speed is right, Speed works. Speed clarifies, cuts through, and captures the essence of the evolutionary spirit.
Re: A disc brake primer - part 1 [Tom A.]
[ In reply to ]
Tom A. wrote:
vjohn wrote:
This was an excellent article, Greg.Agreed. Especially with this part:
"The thing I think we all need to get out of our heads right now is that ALL disc brakes perform better than ALL rim brakes (or vice versa). It’s just not the case. If someone is emphatically making that point to you, I suggest running away or otherwise not wasting your time. There are a TON of factors that influence brake performance, such as rim material, pad material, installation/setup, method of actuation (cable or hydraulic), rotor size, and even frame/fork stiffness. If you want to read more, this thread in our reader forum covers the topic – including a test done by Tour Magazine which concluded that hydraulic disc brakes only resulted in 2-3% shorter stopping distances than standard cable rim brakes."
I have been put off disc brakes while trying to maintain my wife's old commuter which had Avid BB5s. The brakes never perform better than rim brakes because they constantly required attention and a quick google shows I'm not the only one who just couldn't get them setup properly. For years I have maintained difficult to live with rim brakes on my Specialised Transition so I feel like I have a solid baseline in PIA rims brakes but the BB5s were a whole different level. Its going to be hard to convert people like me to the magic of discs who have been jaded by bad experiences.
For those interested - Part 2 of the article just went up on the front page: https://www.slowtwitch.com/...r_-_Part_2_6982.html