Shimano R9150 RD - Why so few direct mount hangers?

Discuss light weight issues concerning road bikes & parts.
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TonyM
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by TonyM

The external Di2 junction boxes on many Pro team bikes at the TDU really surprised me indeed!

Let’s see if it is still like this at the Giro and TdF.

by Weenie


BdaGhisallo
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by BdaGhisallo

pdlpsher1 wrote:
Sat Jan 20, 2018 6:52 am
Because the industry is slow to adopt new technologies. Period. Look at the TDU bike tech galleries. Every Di2 equipped bike still has the external Di2 junction box.

Rather than wait for an off-the-shelf bike to offer the latest technologies I went with a custom Ti bike. My bike has DM brakes, DM hanger, internal Di2 bar-end junction box, and a T47 BB shell. Try find a mass produced bike with a T47 BB.

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What bike did you get? And I'll look forward to your update once you get that road specific DM hanger.

jih
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by jih

pdlpsher1 wrote:
Sat Jan 20, 2018 1:02 am
Also, I must say after switching from a non-shadow to a shadow RD I noticed an improvement in shift quality.
For the pros, they're not out there to marvel at how lovely their shifts are, like we do. So long as the rear shifts aren't making them slower (ie, any current groupset set up right) it's the same.

I'm as much of an equipment geek as you are, but it's understandable that the pros are conservative where the improvements are small and a single failure can mean losing a career-enhancing opportunity.

BdaGhisallo
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by BdaGhisallo

jih wrote:
Sat Jan 20, 2018 2:11 pm
pdlpsher1 wrote:
Sat Jan 20, 2018 1:02 am
Also, I must say after switching from a non-shadow to a shadow RD I noticed an improvement in shift quality.
For the pros, they're not out there to marvel at how lovely their shifts are, like we do. So long as the rear shifts aren't making them slower (ie, any current groupset set up right) it's the same.

I'm as much of an equipment geek as you are, but it's understandable that the pros are conservative where the improvements are small and a single failure can mean losing a career-enhancing opportunity.
That is all very true but often a decision such as this would not involve the riders. The team technical staff along with the bike and component suppliers would get together on this and make a decision to change or stick with what works.

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wheelbuilder
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by wheelbuilder

TonyM wrote:
Sat Jan 20, 2018 7:04 am
The external Di2 junction boxes on many Pro team bikes at the TDU really surprised me indeed!

Let’s see if it is still like this at the Giro and TdF.
I imagine that external junction A's are far easier to work on in regards to moving components from one bike to another for the team mechanics than bar end units. At least they are much faster to deal with for me.

wingguy
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by wingguy

wheelbuilder wrote:
Sat Jan 20, 2018 9:03 pm
TonyM wrote:
Sat Jan 20, 2018 7:04 am
The external Di2 junction boxes on many Pro team bikes at the TDU really surprised me indeed!

Let’s see if it is still like this at the Giro and TdF.
I imagine that external junction A's are far easier to work on in regards to moving components from one bike to another for the team mechanics than bar end units. At least they are much faster to deal with for me.
And particularly at the TDU the mechanics are working with limited toolkits in ad-hoc workshops quite the mobile HQs they travel with on the european circuit, and no access to their main Service Course. Would be surprised if we don't see a lot more bar-end junctions once everyone's back at home.

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Calnago
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by Calnago

1) All the Direct Mount hanger does is alleviate the need for the b-link. The derailleur ends up being in the same position in space that the derailleur would be if the b-link was used to attach it to a regular hanger. That's the intent of the b-link.

2) Shifting is the same whether you use a Direct Mount hanger or the B-Link plus Regular hanger. The derailleur is in the same place under both scenarios. While it is true that while the old 9000 rear derailleur body is more directly underneath, this does not affect how easy or difficult the rear wheel is to remove. But positioning the 9100 rear derailleur further rearward along with new geometry and long cage for lots of chain wrap does allow for the use of bigger cassettes.

3) What makes the rear wheel more or less easy to remove is a combination of the new derailleur design and the frame it's attached to. With long chainstays, a reasonably sized road tire, and good frame clearance between the rear tire and the Bottom Bracket shell, there should be no problem with rear wheel removal. For road bikes with nice tight road race geometry, which means relatively short chainstays, one can run into problems with the new setup. Here's the "perfect storm" scenario where you're likely to have issues with the new derailleur design regardless of whether you're using a DM hanger or a regular hanger:
- Short chainstays
- larger tires
- a frame with a lot of material behind the center of the Bottom bracket.

Here's why:
With the new rear derailleur design, the rear wheel needs to come further forward than before to clear the pulleys and chain of the rear derailleur upon removal. Also, the new derailleur seems to have less rearward pivoting room than the old design. So, it should be apparent that short chainstays, fat tires, and lots of material behind the bottom bracket could cause the "perfect storm" so to speak.

Let's take couple of examples....
I've installed the 9100 derailleur on the Emonda. No problems at all with wheel removal. Unfortunately, this was not at all the case with the last road bike I installed a 9100 derailleur on. I then wondered what was it about the last road bike that was causing the rear wheel removal issues. Well, that other bike had a whole lot more material behind the Bottom Bracket than the Emonda, where there isn't nearly as much material, and thus more clearance. That was the difference, yet that other bike had no issues with the older rear derailleur design (9000). So, same frame... old derailleur no issues, but new design... issues.

If you're a mechanic in a shop with time and access to both the new design and old design rear derailleurs, I encourage you to try this for yourself on some builds that fit the criteria above (short chainstays, fat tires, hefty BB shells). See for yourself which setup results in an easier to remove rear wheel.

My Koppenberg that I just built is one such frame that I could see having issues with rear wheel removal using the new derailleur design but not the old. Especially if 27mm tires are mounted. At some point I'll test this out. When a new chain is required perhaps. That is because of the amount of material behind the BB combined with the shortish chainstays. Even though it shares the H1 geometry with the Emonda, the Emonda has far more clearance in front of the rear tire before the BB shell becomes a factor compared to the Koppenberg. And even though the Koppenberg has a similarly shaped BB shell to the Domane, I don't think the Domane would pose any issues at all due to the comparatively long chainstays it has.

Here's the Koppenberg... rear of BB shell... lots of material, not so much clearance... not an ideal scenario for rear wheel removal with the new Shimano derailleur. Old derailleur, no problem.
Image


And here's the Emonda belwo... rear of BB shell from underneath... note how much more clearance there is between tire and BB shell... no issues with rear wheel removal and the newest Shimano derailleurs...
Image

I guess the main point here is that the choice between installing the new derailleur using a one piece Direct Mount derailleur hanger and no b-link versus a regular hanger with the B-link does not affect how easy or difficult the rear wheel will be to remove. And in fact, I don't think easier rear wheel removal was ever a fact that Shimano tried to market... it was simply a rumor started who knows where. That rumor is false. The advantage to the new design is it's ability to accommodate a wider range of gearing. And depending on your frame design, it could be more difficult to remove the rear wheel, but it will not be easier.

As for shifting precision... to the extent that one setup is stiffer, that will likely be better, but it is not automatic that a DM hanger will be stiffer than the regular hanger plus b-link. You could have a "soft" or a "stiff" hanger under both scenarios, depending on how it's made, the material, etc.

Happy experimenting.
Last edited by Calnago on Mon Jan 22, 2018 2:52 am, edited 1 time in total.

pdlpsher1
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by pdlpsher1

BdaGhisallo wrote:
Sat Jan 20, 2018 12:12 pm
What bike did you get? And I'll look forward to your update once you get that road specific DM hanger.
I posted the details of my bike in another thread. It's here: viewtopic.php?f=3&t=147396&start=30

BdaGhisallo
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by BdaGhisallo

pdlpsher1 wrote:
Sun Jan 21, 2018 3:22 am
BdaGhisallo wrote:
Sat Jan 20, 2018 12:12 pm
What bike did you get? And I'll look forward to your update once you get that road specific DM hanger.
I posted the details of my bike in another thread. It's here: viewtopic.php?f=3&t=147396&start=30
Thanks. I have had a few frames from Carl over the years and he was always fantastic to work with.

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wheelbuilder
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by wheelbuilder

@Calnago....... I have piggybacked with you on another thread regarding this wheel removal issue. I am a mechanic in a shop, and the wheel removal difficulty is a real thing for certain. We have a lot of customers running 9100 on a wide variety of bikes. Most racy, some endurance type stuff. You are 100 percent correct. Thick bottom bracket lay-up and short chainstays on some bikes make for a very difficult wheel removal and nearly impossible installation. On some, the chain has to be broken and removed to install the wheel. Quick links abound on these particular bikes. Its that bad. The derailleur simply wont pivot backwards far enough for the cassette equipped wheel to come in below and around the cage and lower jockey pulley. It has to be slowly inserted at an angle that leaves very little room for error. It is super difficult and frustrating.

wingguy
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by wingguy

wheelbuilder wrote:
Sun Jan 21, 2018 6:13 pm
Thick bottom bracket lay-up and short chainstays on some bikes make for a very difficult wheel removal and nearly impossible installation. On some, the chain has to be broken and removed to install the wheel. Quick links abound on these particular bikes. Its that bad.
I've never seen it that bad on any bike. Any example of which frames you think it's impossible to get the wheels back in?

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Calnago
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by Calnago

I've also never seen it so bad that you have to remove the chain. Are you sure the chain is long enough to begin with? One thing I've noticed is that the B-Screw adjustment can take up a whole lot of slack by itself, way more than previously and certainly more than any Campagnolo adjustment allows. So, I would think maybe in those cases where you actually have to break the chain that perhaps it is simply too short and you should try a longer one in conjunction with playing with the B-screw. But yes, the design certainly can be frustrating, especially when some people seem to be under the impression that the new design facilitates easier wheel changes. Because it most certainly does not. And it has nothing to do with whether they are using a Direct Mount hanger or a regular hanger with the B-Link. I wish Shimano wouldn't keep trying to adapt their mountain bike stuff to road bikes, and if they do, at least adapt it to accommodate for the inherent differences in geometry. Namely, shorter chainstays. And I just can't foresee a day where I will ever be mounting a 42 tooth cassette on my road bike, unless it's to hide the disc brake on the other side. Ugh! I'm afraid if this trend continues, the sports cars of the bicycle world may get lost in the shuffle.

ooo
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by ooo

Deflating tire is not enough?
'

XCProMD
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Location: Cantabria

by XCProMD

pdlpsher1 wrote:The people who have spoken negatively on the DM hanger have never used one. It's funny so many people have opinions on something they have never used before. The person I spoke to at Paragon Machine Works (the owner?) says he has a DM hanger on his MTB and he's never going back. He wishes the industry would adopt it at a fast rate. Cycling is a strange sport such that there's a lot of old 'traditions' that took a long time to overcome. The mechanical to electronic shifting is such an example. Now every Pro bike has electronic shifting. We are seeing the same phenomenon on disk brakes right now.

By the way, a while back I read somewhere (here?) that Shimano has priced in a discount for large volume purchases of the 'shadow' RD without the B knuckle. Presumably this is a tactic to speed up the adoption of the DM hanger adoption.

Also, I must say after switching from a non-shadow to a shadow RD I noticed an improvement in shift quality. The shadow RD has a much higher spring tension in the pulley cage. The high tension keeps the chain slack non-existent and the shifts are quick and silent. To me the shadow technology is a big step forward. I came from Dura Ace 9070. I also have a mechanical Ultegra 8000 RD on my tandem. The mechanical version is also sublime just like the 8050.

Once I received the road specific hanger I will do a comparison and post the results here.
I have had 3 mtb’s and now have a road bike with DM. Still don’t see the point.




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XCProMD
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by XCProMD

wheelbuilder wrote:@Calnago....... I have piggybacked with you on another thread regarding this wheel removal issue. I am a mechanic in a shop, and the wheel removal difficulty is a real thing for certain. We have a lot of customers running 9100 on a wide variety of bikes. Most racy, some endurance type stuff. You are 100 percent correct. Thick bottom bracket lay-up and short chainstays on some bikes make for a very difficult wheel removal and nearly impossible installation. On some, the chain has to be broken and removed to install the wheel. Quick links abound on these particular bikes. Its that bad. The derailleur simply wont pivot backwards far enough for the cassette equipped wheel to come in below and around the cage and lower jockey pulley. It has to be slowly inserted at an angle that leaves very little room for error. It is super difficult and frustrating.
But we needed a new hanger design..


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by Weenie


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