Why no love for direct mount rim brake?

Discuss light weight issues concerning road bikes & parts.
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fa63
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Location: Atlanta, GA, US

by fa63

I have two bikes, one with direct mount 105 brakes and other with normal Ultegra ones. Same pads, both set up by me. Using the same wheels, the DM brakes stop noticeably better.

spdntrxi
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by spdntrxi

Parlee- regular EE brakes
Trek - DM EE brakes

I wish my Parlee had DM Brakes..

by Weenie


ooo
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by ooo

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sram-s-900-direct-mount.jpg
Last edited by ooo on Fri Feb 02, 2018 12:40 am, edited 1 time in total.
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spartan
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by spartan

damn direct knock off shimano's brakes. they even borrowed the aero quick release :roll:
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2017 Giant TCR Advanced SL 0 DI2 9150

fromtrektocolnago
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Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

i'm in the camp classic rim breaks work fine. and since i don't think anyone is arguing that direct mount negates disc brake advantages in wet, i don't see the value. that's not to say if i was buying a new bike i wouldn't consider it, just saying its not a reason to upgrade in my view.
Last edited by fromtrektocolnago on Fri Feb 02, 2018 1:06 am, edited 1 time in total.
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Trek 5200(ultegra)

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Lelandjt
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by Lelandjt

To me the advantage of direct mount was the clean aero integration between the brake and fork (Fuji Transonic SL) without resorting to a proprietary brake.

Vermu
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Joined: Wed Dec 22, 2010 6:39 am

by Vermu

Earlier I had DM brakes and didnt notice difference to normal ones (DA).
Alas then came the red brakes. Now the assembly might have been sloppy, but centering was really annoying (feature of Sram red, not general) and these lacked power as well.
Now on regular EEs and everything is fine. I reckon lm higher end of brakes, DM isn’t really needed. Helps on those that lack power...


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XCProMD
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Location: Cantabria

by XCProMD

We could well merge this post with the one covering Shimano’s DM derailleurs.

Both are a solution only to a Shimano’s problem.


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micky
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by micky

spdntrxi wrote:
Thu Sep 28, 2017 12:58 am
Parlee- regular EE brakes
Trek - DM EE brakes

I wish my Parlee had DM Brakes..
Similar experience, and biggest reason would be aestethic.

Geoff
Posts: 5136
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Having recently acquired an Emonda, I think that there is a clear difference between a direct-mount system and a conventional rim brake. Even if all you did was straddle a direct-mount bike and actuate the levers, you will be able to feel the difference easily. Now, whether it makes any difference on the road or not, I'm not so sure.

Personally, I was fine with my old Super Record brakes (the original Super Record...) Modern brakes are so good, I cannot imagine needing more power or better modulation (basically, the same arguments versus disc brakes for the road). Having said that, is better braking ever a bad thing?

As an aside, they sure look cool...

pdlpsher1
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Location: CO

by pdlpsher1

I have two bikes with DM brakes. Besides the mechanical advantages, they sit much closer to the frame/fork. So they have an aero and aesthetic advantages.


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spdntrxi
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Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

micky wrote:
Fri Feb 02, 2018 9:51 am
spdntrxi wrote:
Thu Sep 28, 2017 12:58 am
Parlee- regular EE brakes
Trek - DM EE brakes

I wish my Parlee had DM Brakes..
Similar experience, and biggest reason would be aestethic.
yes so much so.. I'm actually considering a trek fork from say an emonda, so I can run a DM EE on the front.

pdlpsher1
Posts: 1543
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

spdntrxi wrote:
Sat Feb 03, 2018 2:32 am
micky wrote:
Fri Feb 02, 2018 9:51 am
spdntrxi wrote:
Thu Sep 28, 2017 12:58 am
Parlee- regular EE brakes
Trek - DM EE brakes

I wish my Parlee had DM Brakes..
Similar experience, and biggest reason would be aestethic.
yes so much so.. I'm actually considering a trek fork from say an emonda, so I can run a DM EE on the front.
For my custom Ti bike I chose a Trek Domane fork so I can run DM brakes. The fork is great, and very affordable too. Cheaper than an Enve. The Domane fork comes in three different rakes and multiple color schemes to choose from. Your local Trek dealer can look up the part number on their web system.

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Calnago
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by Calnago

My gosh, looks like another debate over the usefulness, or uselessness, of the Direct Mount Derailleur Hanger... with @Pdlphser1 leading the charge with quotes like...
- Mechanical Advantage
- Better aesthetics
- More aero
- Would never go back to normal brakes
- Those who hate them just haven't tried them
- Blah, blah, blah...

Well, I reread this thread from beginning to end to refresh myself with all the arguments for and against, and I see I actually made a post already in this thread dated July 27th. Everything I said there still stands, and now that SRAM has just entered the market I see they're touting that they've acknowledged one of the pitfalls that I was describing back in July, as "splay". Hmmm... that seemed like a no brainer to me, but no one really wanted to address it... shhhh... let's not talk about the bad stuff... just the good stuff. But SRAM is saying they've worked on that. To quote from their marketing blurb..."The design reduces what engineers call “splay force,...”. Good, because it's real... just as it was in the mountain bike world when cantilevers were mounted to brake bosses on each stay. Hence the development of "brake boosters", when in fact a better name for them might have been "Fork Splay Preventers", but Brake Boosters sounds so much more sellable. So, if you think it was an issue for heavy duty mountain bike stays, just look at how thin some of the road bike seat stays are and tell me that's not something that needs to be thought about if you're anchoring one half of each brake to each stay. Maybe we'd better think about keeping that brake bridge after all, unless you go discs of course.

So now, with more experience under my belt I'm here to reiterate everything I was saying before, only this time with pics, as I know we all like pics.

Let's begin with saying that I believe Shimano currently has the best rim brakes on the market. Better clearance than Campy (which is really the only thing giving them the edge, but it's still an edge in today's world of larger tires). Super stiff. Easy to set up. Great stopping power. Great modulation...but that mostly depends on proper initial setup of the other components involved, like how smooth are the levers and most important of all, how smooth is the cable routing and how free of friction are they. More on that later.

In a nutshell, I'll say that DM brakes do not work any better and have more pitfalls that standard mount brakes, assuming the setups like levers, cable routing, etc. being equal. Plus, we now have disc brakes. Any possible arguments for DM brakes over standard mount brakes are completely blown out of the water since if those arguments are of any concern at all to you, then you should just immediately jump to disc brakes. What arguments might those be?... Tire clearance is one I hear... yet both the the newest Direct Mount and Standard Mount brakes from Shimano have the same tire clearance of 28mm. 28mm? Pffft... You call that clearance?... get discs if you're really going to use that as an argument. But mostly, it's an invalid argument anyway, because it's untrue. DM brakes from Shimano don't offer any more clearance than their standard mount brakes. Campagnolo's DM brakes offer more height clearance than their current skeleton brakes, but they get squeezed in on the sides and they're finicky to set up in comparsion. Bontrager's speedstop brakes... uh... more on those in a bit too.

Where to start... well how about aesthetics... I can't believe people are arguing that DM brakes are aesthetically nicer, although aesthetics are totally subjective, so let me present a couple pics...

Pic 1...
Image

Pic 2...
Image

Quick... which one of the two brakes above do you like the looks of more? And which one is the Direct Mount and which one is the Standard mount? And which one do you think has more clearance? Oh, and my favorite, which one is more "aero"?
Time's up! I purposely didn't label the pics above to prove a point. Point being, kind of hard to tell isn't it?

Ok... so that's Shimano... kind of look the same to me... or perhaps I was just fooling you and they are both direct mount, or maybe they are both standard mount. Anyway, let's move on to Trek and Bontrager...

Here's an SLR Emonda with Bontrager's DM brakes... so "beautiful", isn't it?
Image
What a contraption that thing is. And try cutting the cable end as it goes underneath everything for nice easy access, not to mention if you have to loosen it off for some reason then reroute the same super short cable. Good luck. Here's something I do like however... but haven't had a chance to actually test it yet with both Campy and Shimano levers, that being there's supposedly a cam type adjuster that allows you to adjust the rate of pull to better match the levers you're actually using, which is different for Shimano and Campy. That would have been nice when I built up my Koppenberg because I initially was going to go with the new 9100 brake calipers even though everything else (aside from the pedals) was Campy. Just couldn't get the Shimano calipers to work acceptably with the Campy levers, so my rain bike will be getting an upgrade from 105 calipers to the new 9100's. Quick off topic here, is that I'm running Campy levers with Shimano calipers just fine on my rain bike so I was very puzzled why that combo didn't work so well on my Koppenberg. Has to do with rim width. The rims on my rain bike are 20mm external width Nemesis rims, whereas my Campy Carbon rims are the newer 24.2mm width. Because of the different progressive pulls, you can get away with the Campy lever/Shimano caliper combo on the narrower rim, but not so much on the wider rim, but I'll save that for another post when I eventually swap them out. So, if the 9100 calipers had an adjustable cam to accommodate that mismatch, I might have been fine to use Campy levers with the 9100 calipers. But Shimano and Campy have never gone out of their way to make their components work with the others, nor am I saying they should, "it's just bidness". Don't worry, I had long gotten over the shame of having SHIMANO logos plastered all over the frame while slapping big Campagnolo logos every where else. Ha. But I digress... talking about aesthetics... just beautiful, aren't they. Actually, I'm sure there are some that love that look, so good for you. For me, not so much. Like I said, it's subjective. Do you like collecting dirt and grime in tiny crevices?... these are definitely for you.

I guess the biggest question I have about the Direct Mount brakes is simply... Why? The choice between road brakes these days is between rim brakes and disc brakes. I like having the choice, but I see no point in pursuing a new rim brake design at this point, unless it would be hydraulic calipers, but that's another topic as well.

Frame design... With Standard Mount brakes we have one simple hole, non threaded in the center of the fork crown or rear brake bridge. Can't get any simpler than that. It's strong and doesn't break or wear out. There's no potential for "fork splay", and the designs (in particular Shimano 9100) are so good that I'm not wanting for anything more. They are simple to work on and adjust. Mine never get knocked off center, but I do torque them to spec. If yours at getting knocked side to side from simple wheel removals and the like or even a good hard knock, you need to check the torque on the brake mounting bolt. And they're nice to look at, at least to my eye. Plus, they work. And no, I don't believe DM brakes function any better.
With Direct Mount brakes we now have a different animal as far as what needs to be done to the frame. Two blind threaded holes have to be drilled for each brake into the frame, front and rear, one hole in each fork stay and one hole in each seat stay. Keep in mind that the only reason these things came into being in the first place was because some marketing genius said "hey, if we tell triathletes that they'll be more aero if we put the brakes underneath the chainstays and behind the bottom bracket, they'll eat it up". But the only way they could mount them was by drilling into the bottom of each chainstay. Not too many brake placements like that these days, for good reasons, and virtually none on road bikes that I'm aware of. I'm sure there are a few, but you get the point. But let's get back to the drilling of threaded blind holes in the frame. They better be perfectly aligned, straight, and hopefully no hamfisted mechanic will strip, crossthread, or otherwise destroy those threads at some point in the frame's life. Or even just galvanic corrosion occurring from never removing the brakes and/or failing to apply proper antiseize. To anyone who's ever tried to remove a seized bottom bracket or seatpost binder bolt or waterbottle bolt or basically anything threaded and not maintained very well, there is no reason to think the same issues won't occur here. So why add it? The current system is so simple with no threads to ever destroy. Oh, and once again, they don't function any better.

So as to their function... granted, they both work. But I'll bet that with all else being equal, shift levers, cable condition, brake housing routing, squared off brake housings, etc., you would not be able to say they function any better. I read @Geoff's previous comment about his new Emonda's DM brakes being so superior and if you were to straddle a bike in a store you would see that right away. Well, I did just that, except took one out for some miles. The brakes were rough. Very rough. But it wasn't the calipers... and I suspected as much. When I got back I noted how terrible the braking "felt"... gritty etc. I asked if we could just unbolt the brake cable and have a look at the housing. Sure enough, the housing wasn't finished at the ends and this was what was causing the bad feel, that "pigtail" of curled steel from an unfinished cut. I had that same gritty feeling on my C60 rear brake when I built it and knew it was the rough inner edge of the carbon entry points for the cable that was causing the problem. So, I suspect if you can feel a noticeable difference between the calipers, then it's simply a setup issue.

Bottom line is I see more disadvantages to the DM brakes than Standard Mount brakes, and since every road frame in the world up until very recently uses Standard Mount, why try to switch to something that doesn't perform any better, and especially at a time when discs are being pushed so hard. If the only reason you're doing it is for "added clearance" then I say that is simply not the case and even it was marginally better, that discs would still blow it out of the water as far as clearance issue goes. The road bike braking choice should be bewteen Standard Mount road calipers and disc brakes. I'll give SRAM a pass on their attempt to introduce a new Direct Mount brake only because their standard mount brakes are just so subpar when compared to either Shimano's or Campagnolo's.

And as for "mechanical advantage"??? Please. The last time I heard that was when SRAM tried selling the "mechanical advantage" of their drive trains, simply because they were the only ones without an electric offering. The industry is so weird (sorry @Beeatnik, but I like your expression so much I had to use it, it just works sometimes.)
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

pdlpsher1
Posts: 1543
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Haha. You forgot to take a side shot. The aero and looks advantages come from the side view. One picture is worth a thousand words. I will take a pic comparing the two tomorrow and post it here.


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by Weenie


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