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Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science
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Just finished watching this video and wanted to get ST's feedback.

Thoughts.


http://gcn.eu/DvR


AERO & LIGHT is RIGHT

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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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BMANX wrote:
Just finished watching this video and wanted to get ST's feedback.

Thoughts.


http://gcn.eu/DvR

Seemed like a poorly designed test to me - Only one run per disk vs rim bike in dry and wet conditions each. Plus the guy admits that he had more confidence descending on the disk bike. That by itself could account for the differences. It would be difficult to conceal which bike was being ridden like in some of the aero vs regular frame tests for "feel". Disks sound and feel too different.
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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I won't say that GCN does science as much as they collect anecdotal evidence. Nothing wrong with that but I would think that really demonstrating difference between the two braking systems would require some pretty careful analysis.
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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Not hard science, but certainly food for thought.

But some huge problems with this test:

The rim brakes are very significantly handicapped. Rim brakes on carbon rims are generally poor, and they are absolute sh*t on carbon rims in the wet. But rim brakes with optimal brake pads on AL rims are excellent, and they're pretty reasonable on AL rims in the wet (again, this is with the right rim brake pads; with bad pads this is not case).

It would really be interesting to see this test repeated with both systems optimized but with, say, a 215 lb rider in 95 deg temps and direct summer sun. I wonder how things would pan out then. Because disc brakes have some, uh, interesting (i.e., very scary) failure modes in high heat and high brake loads ...

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Last edited by: DarkSpeedWorks: Jul 16, 17 11:34
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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BMANX wrote:
Just finished watching this video and wanted to get ST's feedback.

Thoughts.


http://gcn.eu/DvR


These plots from SRAM is about all you need to know about the validity of that video. The Red caliper isn't even the strongest rim brake they make, and braking on wet carbon sucks. Throw a HydroR rim brake and a wheel with a PEO coated or machined/textured alu track in the mix, and it's quite possible it could leapfrog the disc performance...seriously.





http://bikeblather.blogspot.com/
Last edited by: Tom A.: Jul 16, 17 13:49
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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Sigh....

I do't even know where to start, there are so many things wrong with this testing/analysis.

get comfortable being uncomfortable
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [DarkSpeedWorks] [ In reply to ]
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Was thinking this too, that an alum brake track could hAve a real difference in that test.

It's "citizen science" for sure, though they recognize the lack of proper sample size and variables at play. Anecdotal evidence, I like that term. Food for thought. Gotta love GCN!

I feel discs are the future for a reason other than better brake "feel". Its the liberties it gives in terms of frame making. If all anecdotal or real-world evidence points to GENERAL aero and braking performance equality between the two (in dry weather - I think it's already accepted discs are better in wet), discs are going to win because of what you can do with tire clearances and other frame subtleties that come about when you aren't burdened by the need to put a caliper on there. Rims will follow and get better due to no need for brake track, so on, so forth. I don't think this point is news to anyone, and certainly it isn't to GCN, but its worth noting anywhere when having a "are discs the future" discussion. It's not just about the braking.
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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GCN does science.

HAHAHAHAHAHA!!!!
Last edited by: Tibbsy: Jul 16, 17 13:53
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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Carbon rim brakes are shit in the wet? Two weeks ago I did a nice mountain descent -6 to -10% for 13mi. in the rain no less and found my Enve (clincher) wheels performed wonderfully. Granted I wasn't racing but we did reach 42mph on a couple of the straights. Had lot of turns so I got a chance to really test the braking. Other than more lever effort I did't find the braking lacked modulation or strength. My son led the way down on Zipp 404's and never heard a complaint from him either. He left me for dead by the way, so his speed was greater by a bit. I have a gravel/cross bike with discs so they are not alien to me. I just feel they aren't head and shoulders above the rim brakes. Equal IMO. But I believe the terms safety and modulation are grossly overused by the journalists and marketing people. Prudent use of the equipment you have and the mental capacity to use it are far more important issues. Could I have gone quicker on discs? I doubt it. Ultimate grip is decided by my tire choice right?
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [Tom A.] [ In reply to ]
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Tom, when I saw what wheels they were using for the rim brakes I immediately thought of you and these exact reply. Why not use the best rim brake options vs the best disc brake options. I know why they don't because the results would not be close any longer.


AERO & LIGHT is RIGHT

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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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It's because no one rides AL rims any more. smh
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [Nazgul350r] [ In reply to ]
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My $0.02 on road bike disc vs rim brakes: disc brakes are marginally better for stopping power in the wet and noticeably better for modulation\feel
They're roughly equal in the dry

I have a stable of road bikes with mix of carbon and Al wheels; and one commuter bike with a set of really low end Tektro mech discs brakes.

res, non verba
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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"GCN Does Science"

LOL

So scientific they didn't bother to use the same depth rims for both bikes (how hard could it have been to find 303 NSWs?)

WTB: TriRig Omega SV (not x). PM me if you have one :)
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [PBT_2009] [ In reply to ]
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PBT_2009 wrote:
Was thinking this too, that an alum brake track could hAve a real difference in that test.

It's "citizen science" for sure, though they recognize the lack of proper sample size and variables at play. Anecdotal evidence, I like that term. Food for thought. Gotta love GCN!

I feel discs are the future for a reason other than better brake "feel". Its the liberties it gives in terms of frame making. If all anecdotal or real-world evidence points to GENERAL aero and braking performance equality between the two (in dry weather - I think it's already accepted discs are better in wet), discs are going to win because of what you can do with tire clearances and other frame subtleties that come about when you aren't burdened by the need to put a caliper on there. Rims will follow and get better due to no need for brake track, so on, so forth. I don't think this point is news to anyone, and certainly it isn't to GCN, but its worth noting anywhere when having a "are discs the future" discussion. It's not just about the braking.

I'm sorry, but those are both "marketing points" put out that have no basis in fact. Frames and rim brakes have always had the ability to be easily designed accommodate tire sizes up to the point you probably don't want to be on a road bike anyway. It's only in recent decades that frame designers didn't leave space for wider tires in frames and forks, and the current batch of road calipers are all typically what is known as "short reach" models (which can still accommodate tires up to 28mm wide, typically). What used to be known as "Standard", or mid-reach brakes can easily accommodate tires >30mm wide. In fact, I have a 1986 Bianchi road bike that fits 30mm wide tires front and rear with no problems.

The whole "rim shapes can change if you don't have to brake on them" speculation is really just wishful thinking...look at the high end aero rims right now. They all basically ignore the fact that the brake track is there, in regards to the shape, and they form nice smooth airfoil shapes already. How would they change that to make them more aero? Make them LESS like an airfoil?? Makes no sense...



http://bikeblather.blogspot.com/
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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This Slowtwitch article from less than a year ago is a better analysis

http://www.slowtwitch.com/Tech/Disc_and_Rim_Brake_Aero_Drag_6073.html


The GNC guys provide more of a personal or anecdotal look at the difference and how it feels.


For me, much to the contrary of Nick over at Tririg who insists rim brakes are more areo than disc brakes and purposefully overlooks data showing this not be true, I believe based on the slowtwitch study I linked above that rim and disc brakes are nearly identical in terms of aerodynamics. Both can be made to be more aero with fairings such as Tririg does with its rim brakes and Parlee does with disc brakes.


So, if they are aerodynamically similar, then we need to look at other factors. I believe from much experience that disc brakes are better than rim brakes. I am not legally allowed to say more due to the terms of a settlement with a major manufacturer and their rim brakes, but I can assure you that rim brakes are not as safe as disc brakes. I have been in one collision with an oncoming car due to rim brakes and if anyone reading this decides to use disc brakes instead of rim brakes an avoids one accident, their training will be better and their racing better without knowing the alternative of being in the hospital and missing months of training and racing.


Beyond accidents though, rim brakes can be limiting. There was one race I stopped even though I was leading my age group by about 30 minutes because the wet hilly conditions were too unsafe in my opinion for using rim brakes. Also, there are many times in training that conditions are wet when disc brakes are much better and since I use carbon wheels for racing, even when it is dry, disc brakes are better than rim brakes on carbon rims. I also dislike changing over the brake pads when I change over my wheels from training aluminum wheels to carbon race wheels, but this is minor and not as important as the safety factors.


If you only race in dry conditions on aluminum rims, than I could see rim brakes being a better option. If you ever have a wet race or you ever train in the rain or you have carbon wheels, I see disc brakes being better. My concern about disc brakes is not their superiority, but the lack of availability on triathlon bikes right now. I think the three triathlon bikes with disc brakes - the Cervelo, Diamondback and Parlee are all great bikes. But, for me, they are all quite expensive. My current bike is a 2004 Cannondale Ironman that I bought for $650 and updated the components to SRAM Red mechanical 10 meaning I am not a $10K bike kind of guy.

2018 Races: <a href="http://www.ironman.com/...a.aspx#axzz4wcgWtkns">IM Santa Rosa</a>, <a href="http://www.vineman.com/...te_Rio_Triathlon.htm">Vineman Monte Rio </a>, <a href="http://laketahoetri.com/...tahoe-half-triathlon">Lake Tahoe 70.3 </a>
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [grumpier.mike] [ In reply to ]
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grumpier.mike wrote:
I won't say that GCN does science as much as they collect anecdotal evidence.

Very true!

Anecdotes presented as science can be very misleading.
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BMANX] [ In reply to ]
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Another issue with disc brakes:

Have you ever tried to switch out a traditional rear wheel and then have had to curse the fact that different manufacturers can't seem to put their freehub bodies in the same point in space on their hubs? And then you had to completely re-adjust your shifter indexing?

Well, get ready for a lot more hassle. Disc brakes have much much closer tolerances to where the disc rotor cam be in space. If that rotor is off by even a little bit, you gotta completely re-adjust (sometimes move) the disc caliper assembly. Every single time you switch out to a different brand of rear hub.

Now Available: the High-Capacity Speedpack 915/915D Series. Advanced Aero Storage, made in the USA.
DarkSpeedWorks.com......Reviews......Instagram......Facebook

"Why would you want to be the last man alive on a sinking ship?" -- Elon Musk on why Tesla Motors shares its patents with competitors.
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [Sanrafaeltri] [ In reply to ]
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I'll go ahead and warn you of the following statements about to come your way:

  • You weren't using HED Jets
  • You weren't using HED Jet Blacks
  • Your brake pads were not Koolstop Salmon
  • Your levers weren't good enough
  • Carbon in the rain makes you dumb
  • You could have avoided your accident with metal brake tracks
  • The study you linked to by Damon Rinard is bogus because "it's not best in class" on either bike
  • With the right pads and right rim you could have stopped faster (which basically means you should have been on HED Jets because apparently that's the only "best in class" rim ever used in these discussions)
  • Disc brakes aren't aero
  • You don't know what you are talking about because you are not a mechanical engineer
  • Damon Rinard is basically lying to everyone and trying to sell bikes. Funny how the anti-disc brake crowd loved him when he worked for Cervelo developing rim brakes
  • The bike manufacturers have this conspiracy to sell more bikes
  • The statements from Cam Piper, Damon Rinard, Karl Hall, and others who are experts in their field mean nothing because they are "pro-disc brake"
  • Kiley's Wind Tunnel shootout results are pointless because the disc brakes weren't taken off to show how much faster a P5-X might really be
  • Only Tom A. can approve of what bikes and wheels anyone can ride
  • and the list goes on and on and on and on


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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BryanD] [ In reply to ]
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lol the anti-disc brake people sound like the anti-full suspension people, the anti-V brake people, the anti-disc brake on mountain bike people, the anti-power meter people. Nice to see some things remain the same even as the bikes get better.

#confirmation bias
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [elf6c] [ In reply to ]
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Don't forget the anti-electronic shifting people! Now, everyone wants it and can't imagine life without it. The reality is people hate change.

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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BryanD] [ In reply to ]
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BryanD wrote:
I'll go ahead and warn you of the following statements about to come your way:
  • You weren't using HED Jets
  • You weren't using HED Jet Blacks
  • Your brake pads were not Koolstop Salmon
  • Your levers weren't good enough
  • Carbon in the rain makes you dumb
  • You could have avoided your accident with metal brake tracks
  • The study you linked to by Damon Rinard is bogus because "it's not best in class" on either bike
  • With the right pads and right rim you could have stopped faster (which basically means you should have been on HED Jets because apparently that's the only "best in class" rim ever used in these discussions)
  • Disc brakes aren't aero
  • You don't know what you are talking about because you are not a mechanical engineer
  • Damon Rinard is basically lying to everyone and trying to sell bikes. Funny how the anti-disc brake crowd loved him when he worked for Cervelo developing rim brakes
  • The bike manufacturers have this conspiracy to sell more bikes
  • The statements from Cam Piper, Damon Rinard, Karl Hall, and others who are experts in their field mean nothing because they are "pro-disc brake"
  • Kiley's Wind Tunnel shootout results are pointless because the disc brakes weren't taken off to show how much faster a P5-X might really be
  • Only Tom A. can approve of what bikes and wheels anyone can ride
  • and the list goes on and on and on and on

To clarify, I was using metal rims on Mavic wheels when I had my accident. I was not using Kool Stop pads, if I had been, I probably would have been ok since it was dry and they are very good pads. I cannot disclose the pads I was using.

In the race I stopped I was using carbon aero wheels, like most triathletes. I was using the brake pads specified by the manufacturer and that combination was not safe enough for me, given the wet and hilly conditions with the problem being rim braking on carbon and not the wheel or pad manufacturer.

In terms of the study, it is not "bogus" specifically because it does not compare best in class. Best in class wasn't available at the time of the study for disc brakes and so it would have been comparing apples to oranges to use best in class rim brakes vs non-aero disc brakes. By using equivalent class rim and disc brakes it created a neutral study. I don't think we have seen best in class disc brakes, but the new SRAM hydraulic brakes and levers and the Parlee disc brake fairing cover are a big step in that direction and could be on the level of aero development by what I believe is best in class aero rim brakes: Tririg's Omega brakes. Redoing that study with top of class rim and disc braked would be a good idea. But, at the time, the best study option was to use rim brakes equitable to the disc brakes available at the time. If they had done anything other than that, it would have created a bogus study whereas the way they did it makes it the exact opposite of bogus.

2018 Races: <a href="http://www.ironman.com/...a.aspx#axzz4wcgWtkns">IM Santa Rosa</a>, <a href="http://www.vineman.com/...te_Rio_Triathlon.htm">Vineman Monte Rio </a>, <a href="http://laketahoetri.com/...tahoe-half-triathlon">Lake Tahoe 70.3 </a>
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BryanD] [ In reply to ]
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BryanD wrote:
Don't forget the anti-electronic shifting people! Now, everyone wants it and can't imagine life without it. The reality is people hate change.

Ummm...no.



http://bikeblather.blogspot.com/
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BryanD] [ In reply to ]
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BryanD wrote:
I'll go ahead and warn you of the following statements about to come your way:

  • You weren't using HED Jets
  • You weren't using HED Jet Blacks
  • Your brake pads were not Koolstop Salmon
  • Your levers weren't good enough
  • Carbon in the rain makes you dumb
  • You could have avoided your accident with metal brake tracks
  • The study you linked to by Damon Rinard is bogus because "it's not best in class" on either bike
  • With the right pads and right rim you could have stopped faster (which basically means you should have been on HED Jets because apparently that's the only "best in class" rim ever used in these discussions)
  • Disc brakes aren't aero
  • You don't know what you are talking about because you are not a mechanical engineer
  • Damon Rinard is basically lying to everyone and trying to sell bikes. Funny how the anti-disc brake crowd loved him when he worked for Cervelo developing rim brakes
  • The bike manufacturers have this conspiracy to sell more bikes
  • The statements from Cam Piper, Damon Rinard, Karl Hall, and others who are experts in their field mean nothing because they are "pro-disc brake"
  • Kiley's Wind Tunnel shootout results are pointless because the disc brakes weren't taken off to show how much faster a P5-X might really be
  • Only Tom A. can approve of what bikes and wheels anyone can ride
  • and the list goes on and on and on and on




http://bikeblather.blogspot.com/
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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [Tom A.] [ In reply to ]
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I'd find memes to post but it's not really worth my time

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Re: Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science [BryanD] [ In reply to ]
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BryanD wrote:
I'd find memes to post but it's not really worth my time

But it WAS worth your time to type out your Strawmen? Whatever...



http://bikeblather.blogspot.com/
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