Thursday Fun: Shimano Direct Mount RD vs. Hanger, in pics
02-08-18, 05:18 PM
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Thursday Fun: Shimano Direct Mount RD vs. Hanger, in pics
There has been hoopla about Shimano's new "Direct Mount" RD for road. The tech came to MTB half-a-decade-ago..Well the new Shimano R8000 stuff brings the tech to road parts, with a removable link in the RD to make it work either way (Direct or Hanger).
With my Bigfoot rig, it uses slider dropouts courtesy of Paragon Machine Works. Part of why I got them is they're not only adjustable WRT rear-center--but you can put anything back there. Single speed disc, or QR hanger disc, or now Direct Mount. PMW now make a slider for 12x142 e-thru axle with Direct now. I needed new sliders as spares anyway (long story for another time) and they're only $13 a shot....so I figured why not give Direct Mount a go.
So we start with hanger dropout configured Di2 6870 GS. For those curious...
Now same dropout and hanger, just with the Di2 8050 GS. Sorry for the angle shot, it is the one that turned out. The removable link is between the silver Allen-head that attaches to the hanger/dropout and the black-allen-head that is the Direct Mounting bolt.
So I got a package from PMW today...pulled the old dropout--but left the hanger-link attached as it was....side-by side with the new direct Mounting hanger:
And one on top of the other. Note this is exact, setup per Shimano's instructions AFAIK. Bolt holes lined up. The DM really does put (relative to wheel axle) the RD maybe 5mm higher and 5mm back compared to an RD hanger.
And mounted. Now, the machining for Direct Mount is *very* precise and snug. Kudos to tolerances to both PMW and to Shimano. That bolt would not thread unless the RD was precisely centered over the hole.
Originally Posted by Pinbike
Direct mount did not need a push from Shimano to initiate. Much of the impetus for a stronger derailleur interface came from frame designers who had begun to move away from the open rear dropout and towards through axles, or grown tired of compromising the drive-side dropout by machining it thin to accept a flimsy replaceable derailleur hanger. The Direct Mount concept simply encourages frame makers to design a link that connects the frame with the upper derailleur pivot. Shimano will not make the link, that is a development left to the individual frame makers.
So we start with hanger dropout configured Di2 6870 GS. For those curious...
Now same dropout and hanger, just with the Di2 8050 GS. Sorry for the angle shot, it is the one that turned out. The removable link is between the silver Allen-head that attaches to the hanger/dropout and the black-allen-head that is the Direct Mounting bolt.
So I got a package from PMW today...pulled the old dropout--but left the hanger-link attached as it was....side-by side with the new direct Mounting hanger:
And one on top of the other. Note this is exact, setup per Shimano's instructions AFAIK. Bolt holes lined up. The DM really does put (relative to wheel axle) the RD maybe 5mm higher and 5mm back compared to an RD hanger.
And mounted. Now, the machining for Direct Mount is *very* precise and snug. Kudos to tolerances to both PMW and to Shimano. That bolt would not thread unless the RD was precisely centered over the hole.
02-09-18, 01:39 PM
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There has been hoopla about Shimano's new "Direct Mount" RD for road. The tech came to MTB half-a-decade-ago..Well the new Shimano R8000 stuff brings the tech to road parts, with a removable link in the RD to make it work either way (Direct or Hanger).
Direct mount derailleurs have been around since at least the early 90's. Some 1991 Paramounts used direct mount derailleurs.
-Tim-
02-09-18, 02:28 PM
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FWIW emailed PMW and this is what they said re: different RD positioning...
Originally Posted by PMW
Our Direct-mount hanger specs are taken directly from Shimano's
standards. The difference in position you're seeing is probably a
result of where the conventional hanger is located. Standards for
conventional hangers are not as well defined, and typically have a lot
of leeway, sometimes as much as 6 mm total tolerance, depending on which
standard is being used.
True, it is a longer lever arm, but it's probably still stronger than
the link that Shimano supplies, and DM eliminates the link and extra
bolt for what could be considered a stouter hanger.
My personal experience with DM is that it is a big improvement over
previous systems.
standards. The difference in position you're seeing is probably a
result of where the conventional hanger is located. Standards for
conventional hangers are not as well defined, and typically have a lot
of leeway, sometimes as much as 6 mm total tolerance, depending on which
standard is being used.
True, it is a longer lever arm, but it's probably still stronger than
the link that Shimano supplies, and DM eliminates the link and extra
bolt for what could be considered a stouter hanger.
My personal experience with DM is that it is a big improvement over
previous systems.
