Shimano R9150 RD - Why so few direct mount hangers?

Discuss light weight issues concerning road bikes & parts.
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ms6073
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by ms6073

I am going to suggest you consider the Wolf Tooth Roadlink DM.
Michael - The Anaerobic Threshold is neither...

barturtle
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by barturtle

ms6073 wrote:
Mon Nov 05, 2018 5:04 pm
I am going to suggest you consider the Wolf Tooth Roadlink DM.
I know of this, but I don't need extra capacity.

What I need is a hanger with a 35 degree stop angle instead of a 25 degree one (and a 10mm instead of a 6mm X offset would be helpful as well). But since it seems (unless I hear back something from the frame maker otherwise), there isn't one being made. But since the XT B Link Is designed for use with a 25 degree stop angle, assuming it fits the R7000 rd, it should place the B Pivot in the correct position.


ooo
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by ooo

barturtle wrote:
Mon Nov 05, 2018 3:38 pm
I have the new R7000 GS and have been having issues with my new build getting the wheel in and out, despite running much smaller tyres than what the frameset claims to fit (32mm, in a frame with 43mm claimed fit in 435mm chainstays.

I've measured as per your directions, and the hanger is not positioning the derailleur correctly, but rotating it around brings it nearly into spec. Looking at the differences between Shimano RD and RD/MTB hanger specs, it appears that my hanger is MTB speced with a 25 degree stop and 6mm X offset, while road specs are 30-35 degree and 6-10mm X offset. I've just contacted the frame maker and am waiting to see if they have a solution, if not I may try putting a XT 8000 B Link into the R7000 RD, as mounting a M772 to the hanger seems to put the B-pivot bolt in the correct position.

One interesting thing I did notice when comparing the DM RD and MTB hanger specs from Shimano is the difference in the stop angles for rotating the body out of the way when removing the wheel. I don't think this was mentioned, though obviously hinted at by those who ground the stop off their B Links. the RD spec is 82.6 while the MTB spec is 65. That's a lot of extra room to swing the deraileur out of the way. Even accounting for the lower stop, the MTB has a range of motion 5.6 degrees more than the RD DM hanger spec.
What was hanger type on your framset, is it direct mount hanger or classic hanger?
It sounds like you have dm hanger and you think you have mtb dm instead of road dm?
Did you mount M772 with or without b-link? Did you mount R7000 with our without b-link?
'

barturtle
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by barturtle

ooo wrote:
Mon Nov 05, 2018 5:47 pm
What was hanger type on your framset, is it direct mount hanger or classic hanger?
It sounds like you have dm hanger and you think you have mtb dm instead of road dm?
Did you mount M772 with or without b-link? Did you mount R7000 with our without b-link?
It's a classic hanger. I found there is a difference in Shimano specs between RD and MTB hanger specs. The derailleurs are being mounted with the B Link.

http://www.peterverdone.com/wiki/index. ... figuration

The different extremes of the recommended stop angles correspond to your earlier post of 10 degree difference in pin location between road and MTB B Links

https://weightweenies.starbike.com/foru ... 0#p1373800

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ms6073
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by ms6073

barturtle wrote:
Mon Nov 05, 2018 5:22 pm
I know of this, but I don't need extra capacity.
Wife and I don't either, but since the bike goes on the Tacx Neo at the end of each weekend, I opted to give the Roadlink Dm a try and have had no issues with DA R9150 drive train with 14-28 Ultegra cassettes.
Michael - The Anaerobic Threshold is neither...

barturtle
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Joined: Mon Nov 05, 2018 2:59 pm

by barturtle

ms6073 wrote:
Mon Nov 05, 2018 8:53 pm

Wife and I don't either, but since the bike goes on the Tacx Neo at the end of each weekend, I opted to give the Roadlink Dm a try and have had no issues with DA R9150 drive train with 14-28 Ultegra cassettes.
Did you need to use the RoadLink DM to clear the 14t when installing/removing the wheel? I've wondered about that, as if I can't get it to clear an 11t, what are the chances of clearing a larger cog...

Have you checked your measurement, as per this post? https://weightweenies.starbike.com/foru ... 5#p1376015

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ms6073
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Location: Houston, Texas

by ms6073

I could get the rear wheel off before, but it took some fiddling and after switching to the roiadlink dm, pull the mech back slightly and the wheel falls out and re-install is just as simple.
Michael - The Anaerobic Threshold is neither...

barturtle
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Joined: Mon Nov 05, 2018 2:59 pm

by barturtle

barturtle wrote:
Mon Nov 05, 2018 6:00 pm
ooo wrote:
Mon Nov 05, 2018 5:47 pm
What was hanger type on your framset, is it direct mount hanger or classic hanger?
It sounds like you have dm hanger and you think you have mtb dm instead of road dm?
Did you mount M772 with or without b-link? Did you mount R7000 with our without b-link?
It's a classic hanger. I found there is a difference in Shimano specs between RD and MTB hanger specs. The derailleurs are being mounted with the B Link.

http://www.peterverdone.com/wiki/index. ... figuration

The different extremes of the recommended stop angles correspond to your earlier post of 10 degree difference in pin location between road and MTB B Links

https://weightweenies.starbike.com/foru ... 0#p1373800
After many emails with the frame manufacturer, it has been discovered the hanger stop angle is well outside of both Shimano and SRAM's road and mtb specs. 10 degrees. Hoping for a resolution.

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Calnago
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by Calnago

A picture would be good here. Because while the hanger stop may be outside the specs, that could be just one of several things that is giving you troubles with removing the wheel. In fact, if the hanger is causing the “B-link” to be more horizontal to the ground, versus angled downward slightly, then that could actually be making it easier to remove the wheel (at the expense of crisper shifting), and an “in spec” hanger could even make it worse. More typically, the problem arises if there isn’t enough clearance between the tire and the back of the bottom bracket, as it prevents the wheel from being moved forward enough while removing, allowing the sprockets to clear the upper pulley of the derailleur.
Try this: Tighten the derailleur to the hanger such that the B-link is parallel to the ground (pointing straight back). Can you remove the wheel easily now? If not, the problem has nothing to do with the angle of the stop on the hanger, and most likely everything to do with the amount of clearance you have between your rear tire and the bottom bracket. Only things you could do in that case are 1) run a smaller tire; 2) deflate the tire every time you need to remove it; or 3) get a completely different hanger which places the rear derailleur way further back than where it is intended to be. I really hate the last option since it really nullifies all the benefits of the newer style derailleurs which by design keep the chain forward and very close to the cogs of the cassette. Placing it further back and/or lower simply gives you very poor shifting performance relative to what it could be when positioned correctly.
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barturtle
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by barturtle

Calnago wrote:
Wed Nov 07, 2018 11:35 pm

Try this: Tighten the derailleur to the hanger such that the B-link is parallel to the ground (pointing straight back). Can you remove the wheel easily now?
Yes, I can, and have already tested this.
Calnago wrote:
Wed Nov 07, 2018 11:35 pm
Only things you could do in that case are 1) run a smaller tire; 2) deflate the tire every time you need to remove it; or 3) get a completely different hanger which places the rear derailleur way further back than where it is intended to be. I really hate the last option since it really nullifies all the benefits of the newer style derailleurs which by design keep the chain forward and very close to the cogs of the cassette. Placing it further back and/or lower simply gives you very poor shifting performance relative to what it could be when positioned correctly.
I'm already running a much smaller tyre than the frame is quoted to fit (32mm in a frame said to fit 43mm).

I'm not deflating the tyre every time, too much risk of losing the tubeless bead.

The hanger is within Shimano (and SRAM, for that matter) Road hanger specs in every way but one, the Stop Angle. The 10 degree angle is 20-25 degrees short of Shimano Spec, and means the mech hits the B-Link's stop before it can swing far enough for the upper jockey wheel to allow the cog to clear.

At this point, I'm hoping, and quite frankly EXPECT, the frameset manufacturer to provide me with hangers that fall within the Shimano Specs.

barturtle
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Joined: Mon Nov 05, 2018 2:59 pm

by barturtle

Calnago wrote:
Wed Nov 07, 2018 11:35 pm
A picture would be good here. Because while the hanger stop may be outside the specs, that could be just one of several things that is giving you troubles with removing the wheel. In fact, if the hanger is causing the “B-link” to be more horizontal to the ground, versus angled downward slightly, then that could actually be making it easier to remove the wheel (at the expense of crisper shifting), and an “in spec” hanger could even make it worse.
Just for reference, the 10 degree hanger angle results in B Pivot measurements of:
24mm to the rear
45mm below

compared to Shimano Spec:
32.65mm+/-1.5mm to the rear of the Axle Center
34.39mm+/-1.4mm below the Axle Center

When rotated back by about 25 degrees the measurements are:
32mm to the rear
35mm below

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Calnago
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by Calnago

@Barturtle: some pics would be really really good at this point. Things seem way off and I’m not sure you’re measuring things correctly or if you’ve even got the derailleur installed correctly. I hope you’re not using a parallel line to the ground as a reference for any of these angle measurements. The two lines of reference are either 1) a line through the axle and the BB center, and other lines along that parallel; or 2) lines perpendicular to that.
Also, what frame are we talking about here? Pics would really help.
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barturtle
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by barturtle

Calnago wrote:
Thu Nov 08, 2018 4:59 pm
@Barturtle: some pics would be really really good at this point. Things seem way off and I’m not sure you’re measuring things correctly or if you’ve even got the derailleur installed correctly. I hope you’re not using a parallel line to the ground as a reference for any of these angle measurements. The two lines of reference are either 1) a line through the axle and the BB center, and other lines along that parallel; or 2) lines perpendicular to that.
Also, what frame are we talking about here? Pics would really help.
Okay. I'm not sure what you don't understand.

Here's Shimano's Spec
image.png
I am measuring this angle against a line perpendicular to the line between the BB center and Axle center, as both your earlier B Pivot measurement, and the Shimano drawing describe.

If you reduce the angle from 30-35 degrees to 10 degrees the B Link rotates counter clockwise and gives the dimensions I stated above, further down and forward of the specs.

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Calnago
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by Calnago

Ok... so the actual point on the derailleur hanger where the B-Link attaches is fine then, correct? It is soley the angle of the stop which you feel is the wrong angle (which is very difficult to actual measure accruately off the bike, let alone on the bike). So then, you should be able to rotate the B-link a bit clockwise and lock it down to the derailleur hanger so that it is parallel to the ground right? Forget the stop on the original hanger for a moment because it is doing nothing when the B-Link is locked in that parrallel position to the ground. If you still can't get the wheel out then there is simply not enough clearance between the tire and the backside of the Bottom Bracket. I have a guideline for the minimum distance needed between the backside of the BB and the center line of the rear axle for a 25mm tubular and that distance is 350mm...
Image

If you are running larger tires, and you are, that distance is going to be greater. The 350mm guideline is just what I use in dealing with road bikes as a go/no go kind of measurement to tell me how likely removing a rear wheel (with the equivalent of a 25mm tubular mounted), may have issues with the new shimano derailleurs.

So, a picture of the current B-link setup you have, and also a picture of the clearance betweeen your rear tire and the backside of the BB shell would be good to see. What frame is it at least?
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barturtle
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by barturtle

Calnago wrote:
Thu Nov 08, 2018 6:27 pm
Ok... so the actual point on the derailleur hanger where the B-Link attaches is fine then, correct? It is soley the angle of the stop which you feel is the wrong angle (which is very difficult to actual measure accruately off the bike, let alone on the bike).
Yes. I measured the angle, and they confirmed the measurement I made, based off their engineering drawings.

Calnago wrote:
Thu Nov 08, 2018 6:27 pm
So then, you should be able to rotate the B-link a bit clockwise and lock it down to the derailleur hanger so that it is parallel to the ground right? Forget the stop on the original hanger for a moment because it is doing nothing when the B-Link is locked in that parrallel position to the ground.
Yes, as I said above, in my eariler response to you, when I do this I can easily get the wheel out.
Calnago wrote:
Thu Nov 08, 2018 6:27 pm
If you still can't get the wheel out then there is simply not enough clearance between the tire and the backside of the Bottom Bracket. I have a guideline for the minimum distance needed between the backside of the BB and the center line of the rear axle for a 25mm tubular and that distance is 350mm...
Image

If you are running larger tires, and you are, that distance is going to be greater. The 350mm guideline is just what I use in dealing with road bikes as a go/no go kind of measurement to tell me how likely removing a rear wheel (with the equivalent of a 25mm tubular mounted), may have issues with the new shimano derailleurs.

So, a picture of the current B-link setup you have, and also a picture of the clearance betweeen your rear tire and the backside of the BB shell would be good to see. What frame is it at least?
Until I have a response on the resolution of this problem, I don't want to post pictures (the hanger has their logo) or name the manufacturer. I'm hoping to get both a properly specced hanger and to hear they are updating the production unit so that it meets the proper specs, so future buyers don't run into this issue.

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