Why no love for direct mount rim brake?

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ichobi
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Joined: Thu Jan 19, 2012 11:30 pm

by ichobi

Have always been curious why manufacturers dont' really adopt direct mount brakes more on newer road bike models? DM brakes have good modulation, less hassle centering the brake when packing bike for travel. Require less frame materials around mounting spot. All with slight weight penalty.

You only see dm brakes on aero bikes mostly, but virtually non existence on traditional climber/ all round bikes. The only model that features dm rim brakes is the Trek Emonda SLR 10 - their top of the line model.

I am sure some of you with insider information must have more insight than me. Or is it because they will move on to disc brake eventually? SRAM for one wont have dm brakes anytime soon according to one of the company rep i met in Taiwan bike show.

Marin
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by Marin

Because classic rims brakes work just fine, and there was no need for a new standard.

IMO direct mount was just a half-assed attempt to introduce a new standard to make existing frames and forks obsolete, but they then found a better way that also forces customers to buy new wheels: disc brakes =0

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Hexsense
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by Hexsense

I really like it.
Using Bontrager Speed Stop + EE rear direct mount brake too. (changed direct mount Dura-ace 9010 out becauese it doesn't play well with ultra wide rim, 9110 fix that but whatever).
They can be a lot lighter than traditional mount version (see EE) or weight the same with better modulation (see Shimano).
And never get knocked out of alignment.

i guess it just come at the wrong time, too late to the party that was disrupted by disc brake. Traditionalist will stay with traditional mount rim brake. New evolutionist will go for disc brake for wider tire clearance than what rim brake will provide. Direct mount rim brake seems like a middle ground. Provide subtle benefit over traditional rim brake.

Zakalwe
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by Zakalwe

I guess because the one place they make sense - behind the bottom bracket - was rightly recognised for being an absolutely terrible idea.

Hexsense
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by Hexsense

Zakalwe wrote:I guess because the one place they make sense - behind the bottom bracket - was rightly recognised for being an absolutely terrible idea.

why on other place doesn't make sense?

I agree that BB mount is not good. seat stay mount is just superior. But how about fork? Direct mount still has lower profile (thickness) which at least would be better in cross wind on the fork, isn't it?

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milesthedog
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by milesthedog

love the EE direct mount brake, and love that the Canyon aeroroad has a direct mount brake.

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pdlpsher1
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by pdlpsher1

I have DM brakes (on the seat stay, not BB). I love them. I can't go back to the old brakes. But boy they are a pain to install!


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ichobi
Posts: 1793
Joined: Thu Jan 19, 2012 11:30 pm

by ichobi

Thats the thing they work really well. I an using dura ace dm on my canyon aeroad which place the rear brake behind seatstay. Terrific modulation and more than enough power. Also allow for more frame design freedom in the rear end.

But i agree with the point of being late to the party and now companies are pushing disc instead.


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Beaver
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by Beaver

It's really a shame - this would have been a real improvement (lighter, better modulation, more power, stay in place) for those who doesn't like/want/need disc.

As on Boonen/Sagans Roubaix:

Image

froze
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by froze

Marin wrote:Because classic rims brakes work just fine, and there was no need for a new standard.

IMO direct mount was just a half-assed attempt to introduce a new standard to make existing frames and forks obsolete, but they then found a better way that also forces customers to buy new wheels: disc brakes =0


I actually agree with this.

I use to race and train all over the mountains of S Calif and never felt like my brakes could be better. In fact all braking is dependent upon the tire's adhesion to the surface it's on. If I can hit the front rim brakes hard enough to cause the front tire to lock up how much faster can a DM or a disk brake stop than doing that? THEY CAN'T! And besides rim brakes are actually better in mountains because the entire rim, which is a disk onto itself, cools better due to the surface area, thus there is less brake fade. Obviously with rim brakes some companies like Shimano makes what I consider to be poor pads, so I only use KoolStop Salmon pads. And then consider to that for years riders have raced down some of the steepest mountains in the Europe reaching speeds of 65 to 70 mph and there isn't a big area of crosses for all the riders that couldn't stop due to crappy rim brakes!

Just month ago a friend bought a road bike with disk brakes so we decided to test the stopping ability of his vs mine with the Koolstops, he felt for sure his were going to be better. So we did 3 test at 20 mph and 3 at 25 mph, in all
6 tests we were equal to within a foot, sometimes I stopped quicker and sometimes he did (which I'm sure is due to reaction timing) but never was either of us more than a foot difference. While it wasn't raining when we did the test, perhaps in the rain he might have a slight advantage, but not sure if that's true since the KoolStops have an instant response even when wet compared to Shimano which were slow to react when wet; I am also pretty sure from my experience with Shimano pads that had the test been done with those pads on he probably would have stopped quicker in all the tests. So yes good rim brake pads like the KoolStop Salmon makes a big difference dry or wet.

Disk brakes are mandatory for CF wheels however, which is why disk brakes are being forced on us. For those of us on regular AL wheels the need simply isn't there. CF rims do not dissipate the heat like AL rims do, and thus they can delaminate from the heat and the rim could fail if it got to hot, not to mentioned increased braking distances due to extreme fade.

Of course I hear the argument about rim brakes wear out the rims, this is true but only after about 35,000 to 40,000 miles unless you don't clean your rims and pads then you could wear them out faster. But the cost of replacing the rims is actually close to the same as replacing all the pads and rotors over that same number of miles, and rim pads are cheap and the KoolStops last a very long time.

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ProfessorChaos
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by ProfessorChaos

I've been seeing more and more of the DM brakes making their way onto regular road bikes. Mostly it's higher end bikes. I like that they facilitate elimination of the brake bridge, and reinforcing the fork crown for a center mount. I really wish we would make the rim version of the Roubaix available to the public with the DM brakes.

I feel like we (Specialized) may be loosing sales by offering disc only on Roubaix, and Venge ViAS (ViAS Rim Framesets are still available). I'm one of the few people that work for Specialized, that is still hearing your concerns about disc brake road bikes, and voicing them to our product teams(maybe it will mean I'll be looking for work soon, but I still feel the customer's wants/needs should always dictate what we make). Sure the Tarmac is still the WW choice in our product line, but I'm one of those weirdos that like a balance of aero and lightweight, and I personally don't want to add 200g to my ViAS for more powerful brakes, I think a lot of people might feel this way. I'd actually like to make it 200, 400, or even 600g lighter, but still retain all the aero benefits. I've descended mountains in the rain on my rim brake ViAS, and I was more worried about the tire traction than braking performance, and this was with carbon rims as well. Feel free to message me with your thoughts on this. I really want us to make sure our company is on the right path, and your input is important to us.

fromtrektocolnago
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by fromtrektocolnago

I have a bike I like, I disdain proprietary standards and the performance gains look to be quite marginal. I'm not into aero and if I was I would focus on my riding style first which is where I would gain the most. With anything I don't look at new stuff that comes out and then decide to use it but rather review what I'm on and only look elsewhere when I'm unsatisfied and believe my solution isn't optimal. If someone thought they needed more braking power disc brakes would eclipse the direct mount solution anyway.
Colnago C-59 (Dura Ace)
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Colnago C-64 disc(ultegra) with Bora 35 wheels

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Lewn777
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by Lewn777

I've never used direct mount, the idea seems fine in principal, but honestly I hardly ever use my brakes on a road bike compared with a mountain or CX bike.
Modern traditional rim brakes from a Shimano 105 level and above work extremely well even with stock pads in the dry, and are so simple to set-up and change the pads. I really don't understand the need to reinvent the wheel with new brakes and add extra weight when what we have works perfectly fine and is so damn easy compared with every other brake, cantis, v-brakes and disks.

About disk brakes; I've used them for many years on mountain bikes. I found the Avid (SRAM) earlier versions finicky and hard to bleed with very small tolerances and some awful warbling in the earlier versions. Shimano in my experience are much better, and I have used and bled and set-up many sets of XT and SLX brakes. After 10 years I've finally become very competent with disks, but still don't really see the point on road bikes. Disk brakes need expertise and maintenance. Nearly all sets of disks come to some extent warped and need to be trued. Disk calipers need to be setup perfectly square. Disk pads and rotors often get contaminated and will need new pads often.

You will need a bleed kit and the proper Shimano oil. You need isopropyl alcohol as a cleaner, a rotor truing tool and ideally a https://www.amazon.com/Hayes-Brake-Roto ... B002SQTRXK.

Oh, and absolutely switch out the disks to floating rotor types, the single piece rotors are garbage.

maxxevv
Posts: 2012
Joined: Wed Feb 09, 2005 4:51 am

by maxxevv

froze wrote:
Just month ago a friend bought a road bike with disk brakes so we decided to test the stopping ability of his vs mine with the Koolstops, he felt for sure his were going to be better. So we did 3 test at 20 mph and 3 at 25 mph, in all
6 tests we were equal to within a foot, sometimes I stopped quicker and sometimes he did (which I'm sure is due to reaction timing) but never was either of us more than a foot difference. While it wasn't raining when we did the test, perhaps in the rain he might have a slight advantage, but not sure if that's true since the KoolStops have an instant response even when wet compared to Shimano which were slow to react when wet; I am also pretty sure from my experience with Shimano pads that had the test been done with those pads on he probably would have stopped quicker in all the tests. So yes good rim brake pads like the KoolStop Salmon makes a big difference dry or wet.



What kind of disc brakes was your friend using ? Cable actuated or full hydraulics ? There is a big gap in modulation and control and to some degree power between the two types.

Also, hydraulic disc brakes isn't about absolute stopping power, its about the level of control achievable with them versus cable pulled rim brakes. Go to a well stocked bikeshop with a range of low end cable pull disc brake equipped MTBs all the way to XTR level hydraulics. Just try actuating the levers from the cable pull ones all the way up to at least XT level.
The difference in feedback, even on the stands is very telling. If you have the opportunity, would suggest trying them out on the trials / roads too. The difference in control afforded especially when going into corners is even greater.

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Hexsense
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by Hexsense

Lewn777 wrote:I've never used direct mount, the idea seems fine in principal, but honestly I hardly ever use my brakes on a road bike compared with a mountain or CX bike.
I really don't understand the need to reinvent the wheel with new brakes and add extra weight when what we have works perfectly fine and is so damn easy compared with every other brake, cantis, v-brakes and disks.

Direct mount from Shimano has the same weight(or lower in some range like 105) vs normal version.
Direct mount from EE, TRP, Bontrager are lighter than their traditional mount counter part.

So if you don't want to add weight, direct mount is the way to go as it can eliminate a center bridge plate of the brake (as it use frame or fork's structure as one)

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