Why no love for direct mount rim brake?

[Hawkwood]

A bit off-topic, but back around 1978 I saw a Peugeot `team bike' in a local bike shop and it had direct mount gold anodised Mafac centre-pulls, it looked really cool.

In fact, it was the standard for commuting or alpine bikes. DM is just a review of that concept.


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[Calnago]

When people talk about standard mount brakes being knocked out of "alignment" I just kind of scratch my head. I've tested this out on my bikes and it would take quite a hit for the brake to go out of alignment. I think I've said this before in my earlier post back in July. Properly torqued to spec it's pretty hard for these to just be moving around willy nilly.
The second thing about alignment, is the pad/rim interface and precise toe-in if used. This is critical. I always want the pads to touch the rim at exactly the same left and right, front to back, top edge/bottom edge. In addition, I like to have some toe-in. These most critical of adjustments involve the same process regardless of whether you are using DM or STD mount, as the adjustment occurs at the brake shoe in both cases. The hard part is holding those pads perfectly toed and aligned while you tighten down the bolt. Then there are the two tiny 2mm screws on Campy SR calipers that allow for some micro adjustment if needed. One to center the pads, the other to adjust spring tension. Lots of people seem to don't even know these exist it seems, and granted if you lock down the caliper perfectly centered in the first place, you probably won't need to touch them. The Shimano 9100 calipers have a similar adjustment.

So far I'm not seeing how the microadjustments are easier on Direct Mounts... Sawyer?

Also, having unencumbered access to the brake shoes and pads is extremely helpful during initial setup. Take my C60 for example... granted this is a pic of the rear brake but the process is the same in the front and the full pad is equally accessible... here you can see I have a piece of cut up credit card at the very back of the pad and lightly against the rim to adjust my 0.75mm of toe-in (the lever is lightly held by a piece of surgical tubing, or inner tube, or even a big elastic band if that works).... allowing the locking shoe nut to be pretty much completely loose at this point so that the pad can settle perfectly aligned with the rim front/back and top/bottom. Then I just tighten it down as I hold it steady with my fingers so it doesn't move while tightening the bolt.




Now... when you try to do this some Direct Mounts, here's the access you have... taken from a couple pics in this thread... trying to get proper toe in and pad alignment is kind of difficult with the rear of the pad pretty much behind the fork while the wheel is installed, and it needs to be as you adjust it...


or this one...


Hmmm... trying to get full access to the brake pad and shoe so that you can manipulate it into a perfect position with repsect to the braking surface while the wheel is mounted is, as I'm sure you can imagine... not exactly easy, in fact it's a frustrating endeavor at best. And if you are lucky enough to get the pads perfectly aligned, try holding that pad steady with your fingers while you tighten the bolt down. Not saying you in particular don't find it easier, just that I can't really see it personally, given what I've just described and shown.

To each his own I guess.

There's another reason I liked the standard mount setup, and I get that it's completely a personal thing with me, but is one reason that I specifically wanted a standard mount Emonda versus the DM Emonda... and that is for fender mounting on my rain bike. I have kind of a unique way of mounting fenders super cleanly, providing you have the clearance, and without the center bolt that just couldn't happen. That's just an aside but it was something I certainly considered when selecting a dedicated rain bike.

[Calnago]

Re those Mafac center pulls a few posts back... I certainly remember those. I know it dates me... but I used to lust after those because I didn't know any better. I had some "lousy" Weinmann side pulls (which of course were anything but lousy). I just thought that "center pulls" had to be better, but I didn't really know why. Maybe I just liked the looks of them. Yes, I think that was it.

[Hawkwood]

Re those Mafac center pulls a few posts back... I certainly remember those. I know it dates me... but I used to lust after those because I didn't know any better. I had some "lousy" Weinmann side pulls (which of course were anything but lousy). I just thought that "center pulls" had to be better, but I didn't really know why. Maybe I just liked the looks of them. Yes, I think that was it.

I'm guessing you're thinking of the Weinmann 500s, ultralight but would never stay centred for me.

[Calnago]

Weinmann 500's... ha, your memory is way better than mine. I have no idea. I was a kid and didn't know squat, except for what I thought looked cool. We all rode Peugot's, Gitanes, Mercier's, etc. with center pull Mafac Racer brakes and Simplex plastic derailleurs... so smooth and quiet... lol. $150 was pretty much the price range... of a "good" racing bike in our budget... you know, like 10sp. And no, that wasn't 10 cogs, but 5 cogs and 2 chainrings.

[Hawkwood]

Weinmann 500's... ha, your memory is way better than mine. I have no idea. I was a kid and didn't know squat, except for what I thought looked cool. We all rode Peugot's, Gitanes, Mercier's, etc. with center pull Mafac Racer brakes and Simplex plastic derailleurs... so smooth and quiet... lol. $150 was pretty much the price range... of a "good" racing bike in our budget... you know, like 10sp. And no, that wasn't 10 cogs, but 5 cogs and 2 chainrings.

Yep 10sp for me too, 52-42 and 13-19 or 21 on the back, and had no problems doing very hilly long club rides in North Wales. The amount of time I spent trying to cobble together bits of worn out Simplex derailleurs to try to get one that would work!

[Calnago]

Nice... I suppose I can't impress you with how far we had to trudge to school in the deep snow each day either? Back then winters were harsh and the snow was deep. We didn't know the climate was changing.

[Hawkwood]

Nice... I suppose I can't impress you with how far we had to trudge to school in the deep snow each day either? Back then winters were harsh and the snow was deep. We didn't know the climate was changing.

I think you can impress me, where I grew up was mainly cold and wet, but not much snow. I did once ride a two-up 25 in snow in Cheshire, that was fun.

[Calnago]

They thought there was the possibility of DM becoming the standard for rim brakes.

@XCProMD... I'm now of the mind that you may be more correct than I was on this subject. So far, I think the Campagnolo offering in the Direct Mount brake department is kind of subpar compared to the quality and function of their standard skeleton brakes. I used them, tested them with various wheels, and have some new conclusions regarding Direct Mount brakes in general, and some specific conclusions about Campy's offering.

First the general stuff. The widest rims I have are Campy Boras at 24.2mm at the brake track. And I still use standard mount rims as well (odler Boras and Ambrosio Nemesis). For these rims I actually prefer the standard mount brakes... the geometry is such that they work very well, are simple, only need one hole (and non threaded) in a brake bridge or fork crown to mount... basically all the stuff that I've already rambled on about. Basically they are good and I questioned the need for something differernt.
But now we have wider rims... some really quite wide. In these cases, I think Direct Mount brakes are the better option. Not so much for height clearance, but becasue of the geometry of the brake arms and the pivot points on the stays. I just think they're better able to handle a rim of more significant width. So, there's the case for Direct Mounts. I'm still not sure if the Direct Mounts do as good a job as standard mounts for rims in the 20mm-24mm width range however. If you need height clearance however, for like 30mm tires or something, then I don't think there's any question that you should be looking at disc brakes.

I know i've raved about the new Shimano 9100 standard mount caliper brakes. They just didn't work so well with my Campy levers and rims even only as wide as my Campy Boras. I wanted to use them on my Koppenberg with my Campy setup. Didn't really work out. But I'm wondering if that combo would be more successful with a wider rim. Reason I'm saying this is that after testing and tearing apart the Campy direct mount offering, I am less than impressed. I think its overall quality is subpar compared to their current skeleton brakes. The rolling bushing between the two brake arms is pretty much completely exposed to the elements, whereas in the skeleton brakes the bearings and/or bushings are all very nicely sealed up and operate very smoothly. Basically, I think Shimano's hammered the rim brake market with their latest offerings and Campy seems to have dropped the ball. So perhaps they really did view the development of the DM brake as something they kind of "had to do" just in case it became a standard, as @XCProMd was suggesting earlier. And their disc offerings seem to be among the best, if not the best, road disc brake system out there, so Campy obviously spent some serious time and effort developing it. I think I've been wrong in assuming that Campagnolo was never behind the idea of disc brakes on the road. I still think they could have just as happily given it an easy passover, but given the trends in the market they seemed to take it serious enough to develop a very good product. Better than very good, excellent. Kudos to them.

Anyway, that's all. The bike I was using for testing all this stuff was a Pinarello K8-S, which ironically had a Campy DM brake caliper in the rear and a Super Record Skeleton brake caliper in the front.

Just thoguht I need to add that update, since I was kind of bashing on Direct Mount brakes becasue I didn't see a need for them. Still don't if you're running standard to a little wider rims. But if you want to go wider and still keep rim brakes... then yeah... DM brakes are problaby the way to go.

Had access to a Pinarello Dogma K8-S for testing out Campy's Direct Mount brake, which was kind of nice because of the DM on the rear and the standard mount on the front. The standard mount was definitely way smoother to operate, but I think that's more a function that the quality of their Direct Mount brake is a little sub-par for lack of a better description. I would like to do the same kind of testing between Shimanos' DM brakes and their Standard Mounts, but from everything I've seen on the Shimano side, they seem to be really almost identical in overall quality.


Lots of clearance on this frame...

[micky]

After all that trashing toward the dm....

[Fiery]

I thought the whole point (at least with Shimano) was that their direct and standard mount brakes are functionally identical. Wouldn’t the preferred solution for Campagnolo’s brake problems then be to develop similar standard mount brakes with offset pivots?

[Calnago]

@Fiery: with Shimano that sort of does appear to be more the case, but if that is the case, then why have Direct Mount brakes at all if they are functionally identical. That’s kind of been my point all along. That they aren’t providing any real benefit performance wise and seem to be more just change for changes’ sake with the added downside of adding big threaded blind holes to your frame. I need to get a test mule with a Shimano direct Mounts to really test.

But with Campys DM brakes, there is a big difference in the pivot points, and certainly a big difference in just how nicely they operate. The skeletons are much nicer, but lack height clearance while their DM brakes give much better clearance as well as better geometry for wide rims.

@Micki: I’m not suddenly saying Direct Mounts are better or worse. But in Campy’s case, I can see that perhaps DM brakes would be a better rim brake option for wide rims. Whereas in Shimanos case, if it’s as @Fiery is stating, and the pivot points of the arms are the same either way (and they certainly appear to be to my eye) then functionally they are pretty much the same so it’s really a moot point which one you choose since they both provide the same clearance. So why even have both. The only reason they were developed in the first place was due to the issues with placing a caliper brake underneath the chainstay and the chainstays were the only place to mount them. That was a bad idea it turns out so then some brainchild starts going on about convincing the masses that they’re more aero, even when not under the chainstay. But now, when you compare the two Shimano offerings side by side I really think you’d be hard pressed to claim one is more aero than the other, even if you’re a hardcore aero advocate. Sheesh, with Shimanos brakes everything I was saying still stands, why have both. I could easily revert back to exactly where I was re my opinion on DM brakes. I only came back to clarify that, with Campy at least, there could be a case for choosing DM brakes over standard mounts for a reason besides change for change sake. And that reason might be if you are using really wide rims. I’m not but others certainly seem to be.

[Nefarious86]

Step 1

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[Calnago]

Ha! Yes of course, you’ve shown that before. Use it. That Pinarello I pictured... bone dry.

[XCProMD]

Cal, I’m with you in two things:

1-Campag DM’s are not on par with their top tier calipers. This is just a fact, they put little resources on them, just developed the kinematics and geometry and left refining for a further effort if needed be.

2-Campagnolo came out with the best disc brake system in the market. I have yet to report on my experiments combining Shimano’s calipers with Campagnolo discs, the other way around and on different frames but long story short the Campags have better clearance and are able to dumper shudder when dirty or wet like no other I system I have tried (
I’m quite a lot into enduro and DH). It took them almost five years though. Magura’s help with the hydraulics was key, but then Magura benefitted from the learnings too and there you have their recent MTB range.


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