Shimano R9150 RD - Why so few direct mount hangers?

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

I appreciate all the feedback on my original question regarding DM hangers. I didn't think I'd spark this kind of quality discussion and it reminds me that this board is peopled by some very passionate and knowledgeable bike lovers. Thanks!

Can I ask one more question of you guys? How does the 9150 RD run in comparison to the 9070 RD? Is it quieter when riding the bigger cassette cogs in combination with the big chainring? That's the one thing I don't like about my 9070 setup. I find the chain makes a lot of noise when I am in the 53 and use any of the top four or five cogs on the cassette. The chain runs pretty silently when on the small ring no matter what cassette cog I am in, outside of the very smallest 12 cog.

For reference, my chainstays are 413mm. I am running an SRM 9000 powermeter and I have often wondered if the chainline is not quite the same as a standard 9000 crank, leading to this 'issue'.

pdlpsher1
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by pdlpsher1

I have the 9070 on another bike. I have noticed more noise when I run a cross chain combo especially on the big ring. This noise is present on both the 9070 and my 9150 with the 8050 RD. So I think the noise is not coming from the RD but rather from the chain exiting the cassette at an extreme angle. A longer chainstay would minimize the noise but not completely eliminate it. Some of the noise could also be coming from the big ring as the chain would be entering the big ring at an extreme angle. I do use the cross chain combos but not for an extended period. In most cases I'm cresting a small rise with a descent afterwards. So it doesn't make sense to shift to the small ring and then shift back to the big ring very soon.

by Weenie


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wheelbuilder
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by wheelbuilder

Thanks to all for the thought provoking responses. Especially pdlpsher for the photos. Definitely something I am excited to investigate when I get back to work. It would be really nice if I have simply not been pulling them backwards at the right pivot points all this time. Seems like I would have figured this out by now, but I can be pretty ignorant at times!

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Calnago
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by Calnago

Well gents... played around with the whole mess again today, and can safely say a solution has definitely not been reached. The limiting factor is still how far the body can pivot rearward. When the wheel drops down, it is going to get caught up a bit in the upper pulley. This issue is going to be one of those "it depends" situations. It depends mostly on the combination of the three factors I already listed, which all boils down to the amount of clearance you have between your rear tire and the BB shell. I played with it every which way but Sunday (no, I played with that way too). On both a thru axle disc bike and a rim braked bike with a normal hanger. In both cases the B-link was in play, and I tried to pay particular attention to whether a Direct Mount hanger might make the process easier. The answer was no it wouldn't, at least on these bikes. Where the hangup was occurring was on that last little bit where you're trying to get the cassette clear of the upper pulley. Could it be done... sure... but it is a pain in the ass compared to how things used to be before the Shadow Derailleur.

Here's the setup, Ultegra Shadow derailleur...
Image


Here it is below pulled as far back as the body will go before hitting the stop, and with the cage almost vertical. The vertical cage part is a red herring. If you do the same thing with no wheel in it, the cage will relax but the upper pulley wont't be in much of different place (i.e., this is as far back as it goes). Looks like the wheel should drop right out, and it would with a regular derailleur in it's place which could also be pulled back a lot a more without the stop that prevents doing that with the new derailleur...
Image


And below is the offending obstruction... between the upper pulley and the cassette. The derailleur doesn't want to come back any further, and the BB up front is preventing pushing the wheel any further forward to clear it... you can get it out, but it's tight, and due to the length of the cage, you would do well with a couple of extra hands to simultaneously push and pull and position everything just right in order to get the wheel out. Basically an annoyingly frustrating task, mostly because it used to be so so simple...
Image


Trying to describe it is a bit like one of those "you had to be there" situations... but meanwhile up front... you've got a jam up as well...
Image


I also tried it with the chain positioned on different cogs, but it was always more or less the same thing playing out.

Conclusion:
Same as I started with... The new shadow derailleurs may make rear wheel removal more difficult in certain situations with some road bikes. And I can't think of a situation where it would ever be easier (but I'm sure there must be one somewhere) than it would have been with the previous generation Shimano derailleurs, or current Campagnolo, or most likely SRAM (I don't have tons of experience with SRAM, but never hear of people being frustrated removing their rear wheel). And whether or not you have a Direct Mount hanger is simply not the deciding factor. The hanger and frames and dropouts all have to be really designed with the idiosyncracies of the Shadow derailleurs in mind. No wonder Shimano is giving incentives trying to get frame manufacturers to design their frames/dropouts around the new hanger. The pics above show the mechanical drive train, but played with the electric version as well at the beginning and it seemed to be playing the same way, but I need to just check it out again to verify that for certain.

As for what someone posted in another thread about Sky's attempt at making this annoying problem less annoying... to reposition the b-link so that it goes against Shimano's Tech Docs and does NOT butt up against the stop, thereby positioning the derailluer body as far back as possible for any given hanger spec. Or even filing some of the stop away to get it to do the same thing, well... so be it. Pinarello frames do have quite a lot of material behind the bottom bracket, so i could see this as a potential issue in some cases... but probably more of just an annoyance. My Koppenberg which I pictured above also shares a BB design with quite a lot of material behind the bottom bracket. Still has plenty of clearance to easily remove a 27mm Vlanderen using a normal (non Shadow) derailleur, but I'm pretty sure (haven't tried yet but someday I will), that the process would become much more convoluted and difficult if Shadow derialluer was used instead.
And I'm also tending to believe what I heard about the newer Trek hangers being set back a smidge over last year... and why do you think they might have done that (if they did)... well, my guess is to better accommodate the new derailleur. They've got to be one of Shimano's largest customers.
Since the post last night, I was curious why I had never heard of what seemed like such an easy solution, but now I know... it's not the solution at all. I searched the internet... couldn't find anything and when I did, it was mostly people asking why it's so difficult to remove their wheel, and whether they were "missing something". They're not. It's just the way it is under certain scenarios. We can deal, and most probably won't have a significant issue at all... but for those that do... it's certainly not an advance. And especially for those who may not care about running mega big cassettes on their road bikes. Why can't we just leave the mountain bike stuff where it belongs... in the dirt.

So there you have it... and one final little video of how I wish things could be, and are, as long as you're not using that Shadow derailleur.
Removing a rear wheel - Keep it simple please
Last edited by Calnago on Tue Jan 23, 2018 4:38 am, edited 3 times in total.

pdlpsher1
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by pdlpsher1

I think you might have a B screw adjustment issue. If you look at my Di2 bike the B screw is properly adjusted and yet the RD swings back very far and there's absolutely no interference. Try adjusting the B screw so that the upper pulley goes back further. And play with your shifting. I bet your shifting will be spot on.

On the same bike but with a non-shadow RD, you have no issues with wheel removal? I watched your video but it shows a Campy RD and not a Shimano RD. And the bike is a different bike, one with a slim BB? I still don't think the shadow design makes wheel removal any worse than with the previous Shimano RD.

pdlpsher1
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by pdlpsher1

Colnago,

Take a look at this pic. I left the gear on the 34 front and 11 rear. On my bike the upper pulley wheel sits just slightly behind the wheel axle. On your bike it’s much further forward than on my bike. Please adjust the B screw so it matches the upper pulley position as my bike. And try to remove the wheel and report your findings.

Image


Sent from my iPhone using Tapatalk

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Calnago
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by Calnago

Pretty sure not a b-screw adjustment issue but next time around the bike (it isn't mine), I will adjust the b-screw to both extremes and see what happens. Bike shifts flawlessly. Tell me why you think the B-screw is not adjusted properly, please. By the way, tell me how can I tell your B-screw is adjusted properly by looking at your photos? The bike in the still photos with the Ultegra shadow derailleur worked fine with the older style rear derailleur. Only when "upgraded" to the new derailleur did this issue rear its ugly head.

The video I made is just an example of how a rear wheel removal should work, and how easy it should be. Campy derailleur, regular hanger, Colnago C60, shifts flawlessly with the added benefit of quick, easy wheel removal and insertion. Easy out, and easy back in... all within 30 seconds start to finish, beginning with a locked in rear wheel. Not possible on that other bike, not even close.

By the way, do you use Tapatalk? Could you (or anyone) check to see if you can see the video and all the photos on Tapatalk? For some reason, some are missing on mine, yet on the desktop computer they all show up fine. This has happened before to me, but I've not been able to figure out why.

pdlpsher1
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by pdlpsher1

On the new shadow derailleur, the B screw adjustment moves the upper pulley up and down, and fore and aft. If you look at the photo you took, the upper pulley is way more forward than mine. When you see the bike again play with the B screw and watch how it affects the upper pulley. And watch how the B screw adjustment affects the chain tension/slack. The shadow B screw has a very wide adjustment range. After you have brought back the pulley to a position just under the wheel axle, shift the chain to the big big combination. Check for the upper pulley to cassette clearance. It should be about 7-10mm apart. Then check for shift performance. Lastly try wheel removal. With the upper pulley further back the cassette should have no problem clearing the upper pulley.

If the B screw is not adjusted properly, after properly adjusting the B screw the chain might be either too short or too long. Changing one variable will affect the other.

Take a look at my pic again and see how big of difference there is between my bike and your friend's bike.

pdlpsher1
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by pdlpsher1

On Tapatalk I can only see the very last pic you posted. And I don't see the link to the video for some reason. I could see all of the pics that I posted just fine on Tapatalk.

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Calnago
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by Calnago

Looking at your photo, I might suggest that it is your b-screw that is quite in need of adjustment. Look at how far the chain is from the sprocket teeth. It's a chasm. It's not even engaging the teeth till about the 7 o'clock position on your cassette. I would hazard a guess that the shifting on the bike in my photos is most likely a lot better and crisper than yours, merely because the pulley is so much closer to the cassette. That's kind of the idea behind any rear derailleur... to keep the chain and upper pulley as close to the cogs as possible throughout the entire range of the cassette without jamming up anywhere. Didn't you say you have the mountain bike hanger on there by mistake. No wonder it's so far rearward. You could probably pull your wheel to the rear and it would still fall out. It's probably designed to accommodate even bigger massive cassettes than the road version. So, we're not even comparing apples to apples here. Post up another picture when you get the proper hanger installed on your bike. I bet it will provide better shifting for you as well.

But I will play with the B-screw at the extremes on the bike in the photos, just to confirm it's not that, and also check for proper chain length. But basically I'm done with this issue... it's very real, that much I'm convinced of. The new derailleur works, and has a larger capacity, but in no way does it make rear wheel removal easier than it was.

And do post up a pic of both your mtb hanger and your road hanger overlayed on each other when you get it please. I presume the hanger was made for that specific frame, or is it some generic hanger? Oh, and thanks for checking Tapatalk. I don't know what's wrong there. I'll try to fix it. Works on my desktop computer but not on Tapatalk, so I'm kind of at a loss, but maybe I'll try deleting and reposting the photos and video to see if that works.

pdlpsher1
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by pdlpsher1

The shadow RD is vastly different from the traditional RD. Trust me. When I'm on the 34-34 (yes, I have a 11-34 cassette) the upper pulley is 7mm away from the 34 cog. On the shadow RD the upper pulley cage moves further away from the cassette the higher the gear you go. That is by design on the shadow RD, not a mis-adjustment of the B screw. When you see that bike again please adjust the B screw and spend some time on the derailleur. My shifting is absolutely perfect. It may very well be my 11-34 cassette that resulted in a particular B screw adjustment. But I can assure you despite conventional wisdom the shifting is perfect. Lastly, the shadow RD has an extremely high return spring tension. This is done so that the upper pulley can be further away on the higher gears and still provide crisp and perfect shifting. In a nutshell, what used to work on prior RD designs cannot be applied to the Shimano shadow RD. It's a steep learning curve for sure. The B screw location is completely different from the prior version's. And the B screw affects many things in a dramatic way. Try play with it and you'll see exactly what I mean. Shimano should rename the B screw to something else since it really doesn't function like a traditional B screw anymore.

My MTB hanger is made to Shimano's DM hanger specification. The hanger obviously is designed to fit my frame's dropout but the overall length of the hanger is no different than another MTB DM hanger made for another frame.

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Calnago
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by Calnago

You're talking to me like I've never installed one of these before. By the way, do you think adjusting the B-screw affects how far the main body can pivot rearwards, or does it just affect how far forward it can go, and in so doing change the tension and position of the pulleys? Make sure you understand that question and know the answer.

Is your bike a mountain bike?? Did you build it from the ground up? Did you set the chain length? If so, which method did you use to set it?

pdlpsher1
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by pdlpsher1

Yes, adjusting the B screw changes how far back the RD can pivot rearward. My two bikes with the shadow RDs are both road bikes. But the one with the DM hanger has a MTB version of the DM hanger. The road version is slightly different in length. I will get a correct one at a later date however the current MTB version works just fine.

I built both bikes from the ground up. I didn't follow Shimano's method. First I left the chain very long. Then I adjusted the B screw. Then I shortened the chain to take out the slack on the small small gear combo.

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Calnago
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by Calnago

pdlpsher1 wrote:
Tue Jan 23, 2018 7:12 am
Yes, adjusting the B screw changes how far back the RD can pivot rearward. My two bikes with the shadow RDs are both road bikes. But the one with the DM hanger has a MTB version of the DM hanger. The road version is slightly different in length. I will get a correct one at a later date however the current MTB version works just fine.

I built both bikes from the ground up. I didn't follow Shimano's method. First I left the chain very long. Then I adjusted the B screw. Then I shortened the chain to take out the slack on the small small gear combo.
Ok... I just kinda shook my head when I read this... the reason I asked the question in the first place, was because it was beoming painfully obvious to me that you really don't understand this whole setup very well at all. So sorry, but allow me to 'splain a few things...

Firstly, in answer to my question to you a couple of posts ago... No, the B-screw does not affect how far the rear derailleur body can pivot rearwards. It simply adjusts the relationship between the pulley cage and the chain. You can screw that screw all the way in or take it completely out for that matter, but the limiter on how far the rear derailleur can pivot rearwards, is right at the back of the derailleur itself when it comes into contact with the B-link...

In the pic below... see the edge of the B-link that I'm trying to point out with the 2mm Allan wrench...
Image


Good... now I'm going to start with the derailleur in it's relaxed position (below)... see the gap below that edge that I just pointed out...
Image


Ok, now I'm going to pull the derailleur backwards, to close the gap at midpoint or so...
Image


With me so far?... ok then... now I'm going to pull the derailleur body all the way back as far as it can go. It will stop as the body comes in contact with the edge of the B-link... and note the B-screw visible directly underneath it...
Image



You can take that B-screw all the way out or screw it all the way in... it's not going to affect how much further you can pull the derailleur body back. If your chain is too short, I suppose that it would be possible that you could not even pull the derailleur body back far enough to even make contact with the edge of the B-link, but that would be due to a short chain. The point is... the derailleur body cannot be pivoted rearward any further once it comes into contact with the edge of the B-link.


Ok, now that that's out of the way, let's address a couple of other things. You said your shifting is "absolutely perfect". I'm not sure you know what absolutely perfect is. I'm sure it's fine, but perfect... not likely based on your pics. One of the main features of the new derailleur is to better "wrap around" the cassette... Shimano wants that top pulley to be in front of the axle, certainly not behind it. When Campagnolo introduced their new mechanical group in 2015, that was also what they were doing... calling it their "embrace" technology. Shimano may have one upped them with their newest design... perhaps to the detriment of some "tight" geometry road bikes. But here's basically what they like to see... pulley and chain as close to the cogs and wrapping as many teeth as possible without jamming up anywhere over the entire cassette range. That's always been the ultimate goal of any bicycle rear derailleur. This new derailleur is an attempt to try to maintain that goal while also expanding the derailleurs capacity. And by and large, I think they've succeeded.

First... a picture of the chain on the largest cog at the back...note how close to the cogs and forward of the rear axle that the top pulley still is... pretty good "wrap"...
Image


Now a pic of the chain on the smallest sprocket... very good wrap and well forward of the axle. This is good. Shimano would like this...
Image


And a closeup of that chain and small cog interface to show where that initial engagement with the teeth is occurring, just shy of the 6 o'clock position...
Image


Ok... I hate to tell you this, but I believe the position that your MTB Direct Mount hanger is putting your derailleur at on your new bike is so far off the mark that Shimano would cringe to look at it. I'm not going to claim I know squat about their mountain bike stuff, but you already said that you got a mountain bike hanger by mistake, and I don't know how they differ, but that would need sorting out in my mind. I don't know if you can mix and match like that, but your setup does not look at all right to me, at least not optimal. Unless that's as good as it gets when running a very large cassette.


So, in closing... what do the Direct Mount hanger setups look like for say... Richie Port of BMC... well, they look like this...
Image

and one more, just including it to show the interesting routing for the Di2 cable, through the hole in the DM hanger which keeps it always clear of the cogs and chain I guess...
Image


Now... ok... after all those pics and explanations... let's have one last look at your setup... if you're completely happy with this, then ok... but I'm standing behind every last thing I've said in this thread, at least at this point as things stand... I'm always open to review if I'm presented with evidence to the cotrary...
Image

That's all folks! In a nutshell the new Shimano stuff works fabulously well in the vast majority of situations. But there are situations where you could have quite a bit more difficulty with rear wheel removal as I've tried to outline in this thread. And if someone starts trying to convince you that it's because you don't have Direct Mount hanger on your road bike... that is complete BS.

by Weenie


pdlpsher1
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by pdlpsher1

Colnago,

Thanks for taking the time to take these pictures. I analyzed the pictures and also played with my RD. I have discovered several things. Firstly, I noticed something right away with your first picture. I can see the B link is mounted incorrectly. There are two raised tabs on the B link. Both of these tabs needs to be above the little hook on the hanger. I found Shimano'a manual that shows a picture of how it should be installed. I don't know why there are two tabs and not just one. It seems the upper tab is redundant. Shimano's manual doesn't discuss the difference between the two tabs. Perhaps the upper tab is there to keep the B link from moving in the other direction. If you raise the B link per the picture shown in the manual then the RD will be positioned much further back. This could affect how far back the upper pulley wheel can be pushed back. Secondly, you are correct that the B screw has not effect on how far back the pulley wheel can go. The B screw does move the pulley wheel forward and I had thought it also controls how far back it goes. I apologize for the mistake. Thirdly, I saw your pic on Porte's BMC bike. I backed out my B screw and it did move the pulley wheel forward. I can only go so far before the pulley wheel interferes with the largest cog (34). I took a picture of the RD in the small-small gear combo. Because I'm running a 11-34 cassette, perhaps my B screw will be different than that of Porte's bike. Additionally, my hanger seems to put the RD much further back than on Porte's bike. Again I have the MTB hanger and perhaps the road version has a different geometry. I will ride the bike with the new B screw adjustment. Prior to the changes I had no shifting issues. And I expect I won't have shift issues with the new setting. Shimano's system seems to be very immune to setting changes.

Please change the B link position on your friend's bike and report back on how that affects the RD's position and how far back the pulley wheel can go. And I will report back any changes in shifting performance with the revised B screw setting. Thanks.

Shimano's installation manual showing the position of the B link

Image

My other bike with the Ultegra mechanical RD with the B link and a regular hanger.

Image

After B screw adjustment

Image

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