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Home > Forum > Triathlon Forum > Direct Mount of Shimano R8000 and R9100 Rear Derailleurs

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Direct Mount of Shimano R8000 and R9100 Rear Derailleurs
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awenborn
May 7, 18 12:11
Post #1 of 10 (4456 views)
I'm planning a couple of minor upgrades to my road bike and was just wondering about the "Direct Mount" option of the Ultegra R8000 and Dura Ace R9100 rear derailleurs. Am I right in thinking that the upper bracket on these derailleurs is used if you're attaching it to a standard derailleur hanger, but if you have a direct-mount compatible hanger then you can remove this upper bracket and bolt it on directly? What are the benefits of doing so and is it worth it? And if this is the case then is it possible to buy able to buy a direct-mount compatible hanger for a Specialized Tarmac SL5?

I just read the Dealer Manual for those derailleurs and it doesn't really mention anything other than how to remove the bracket, so I was hoping you guys might be able to shed more light on the topic. Thanks!
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [awenborn] [ In reply to ]
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exxxviii
May 7, 18 12:27
Post #2 of 10 (4441 views)
That little extension bracket just unscrews off. And then, the RD would connect directly to the hanger bracket on the frame. Shimano’s statement is that this shifted geometry let’s them position the RD better formshifting performance. I have no idea what an advantage would be versus regular mounting. I just took Shimano’s instructions and ran with it.
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [exxxviii] [ In reply to ]
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awenborn
May 7, 18 13:14
Post #3 of 10 (4416 views)
So you can remove the little extension that comes with the derailleur and still mount it on a standard hanger?
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [awenborn] [ In reply to ]
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exxxviii
May 7, 18 13:29
Post #4 of 10 (4410 views)
No, if the frame has a normal derailleur hanber that is positioned below the wheel axel, then you need to use the little extension. If it is a frame designed for the new direct RD, then you remove the extension piece on the new RD and mount what remains of the RD directly to that new RD hanger.
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [exxxviii] [ In reply to ]
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awenborn
May 7, 18 13:38
Post #5 of 10 (4406 views)
Ahh right, yes that's what I thought!

So is it possible to purchase new hangers (official or third-party) that you can mean that you can ditch the little extension bracket?

It seems like the main benefit is a stiffer mounting interface and sharper shifting, so you'd think fewer linkages would be better.

Can anyone point me in the direction for such a thing for a 2016 Tarmac?
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [awenborn] [ In reply to ]
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PMo
May 7, 18 13:45
Post #6 of 10 (4397 views)
awenborn wrote:
Ahh right, yes that's what I thought!

So is it possible to purchase new hangers (official or third-party) that you can mean that you can ditch the little extension bracket?

It seems like the main benefit is a stiffer mounting interface and sharper shifting, so you'd think fewer linkages would be better.

Can anyone point me in the direction for such a thing for a 2016 Tarmac?

I don't think anyone is making aftermarket DM hangers yet. I wish someone would but they likely wouldn't sell very many and almost every bike would need a different one. I've only ever seen these as OE on some new BMCs.
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [PMo] [ In reply to ]
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lyrrad
May 7, 18 20:56
Post #7 of 10 (4355 views)
One of the major benefits is ease of wheel removal, especially if you have bigger tyres that are now becoming popular and a short chainstay.
The standard hanger gets fouled by the wheel axle in a lot of these cases.
Larger gears on the rear cluster also require different geometry in the derailleur and this is best achieved without several long flexy brackets being involved.
The change to larger clusters and fatter tyres is what has driven the design switch to MTB style derailleurs for road.
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [lyrrad] [ In reply to ]
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awenborn
May 8, 18 5:28
Post #8 of 10 (4309 views)
Thanks for the replies.

It's disappointing that there aren't any aftermarket Direct Mount derailleur hangers that remove the need for the bracket.

If I'm spending all that money on a Dura Ace rear derailleur for uber-crisp shifting then it seems like having a potentially flexy linkage system to mount it makes it a bit of a waste of time.
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [awenborn] [ In reply to ]
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lyrrad
May 8, 18 6:03
Post #9 of 10 (4299 views)
It's not generally as simple as a different hanger.
Direct mount is meant to be incorporated onto the axle, hence the direct mount terminology.
This removes the carbon from the equation of supporting the hanger and allows a stiffer interface that transmits crash energy into the axle instead of the carbon frame.
Thru axles and direct mount are a match made in heaven.
No worn dropouts, little chance of mis alignment, in fact many MTB's use this and never seem to ever need aligning even after heavy crashes.

Just another reason why my next bike will be disc braked, thru axle, direct mount brakes and derailleur.
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Re: Direct Mount of Shimano R8000 and R9100 Rear Derailleurs [lyrrad] [ In reply to ]
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awenborn
May 8, 18 6:35
Post #10 of 10 (4280 views)
That makes a lot of sense. Many thanks for the explanation!
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