New Ultegra 12v for gravel

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Loukas
Posts: 16
Joined: Thu Dec 24, 2020 6:28 pm

by Loukas

I'm thinking on the groupset for a new gravel build, would it make sense the new Ultegra 12v for gravel?
The 12v and wireless shifters are obvious pluses over a GRX Di2 11x2, but which would be the advantage of the GRX over the new ultegra in a gravel set up? brakes maybe? clutch?

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pdlpsher1
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by pdlpsher1

Do you currently have a gravel bike? If so what gearing do you have on it? The most obvious difference between the two groups is gearing. The max low gearing on the Ultegra is 1:1. That’s not low enough for serious gravel rides. Keep in mind that gravel tires are wider (and hence taller) and the larger circumference of gravel tires makes the gear ratio taller. So unless you ride on flat gravel roads the GRX is the better choice. The other option is to fit the GRX crank to the new 12-speed. But thus far no one has tried it so we don’t know whether that works or not. It seems that the new 12-speed FD may take a large ring as small as a 46T. But shifting a chainring gap of 17T reliably is questionable.


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ooo
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by ooo

grx on the front have more gear range
grx on the rear have option to ride standard range RD with 1x/2x and wide range RD with 1x/2x
you can use grx shifter st-rx815 with new calipers br-r8170/br-r9270 for extra clearance
'

CampagYOLO
Posts: 706
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by CampagYOLO

No idea about the new generation of Ultegra but with the previous generations Shimano were pretty conservative about the largest cassette you can run on them. An R8000 long cage rear mech could run an 11-40 cassette, I wonder if the r8100 rear mech is the same?

Rotor make 12 speed 11-36 and 11-39 cassettes, it'd be very interesting if someone tried using one on a r8100 set up.

spdntrxi
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by spdntrxi

Easton 47/32 crankset
Ultegra R8170 groupset
Rx-805 RD with goatlink.. running XTR 11-40t cassette no issue. Can run SRAM 10-42(change 42 to 44t ) as well.. just no big-big with that cassette.

at this point with that wide of gearing..no want for 12s on this all road bike
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Loukas
Posts: 16
Joined: Thu Dec 24, 2020 6:28 pm

by Loukas

pdlpsher1 wrote:
Mon Jan 03, 2022 12:48 pm
Do you currently have a gravel bike? If so what gearing do you have on it? The most obvious difference between the two groups is gearing. The max low gearing on the Ultegra is 1:1. That’s not low enough for serious gravel rides. Keep in mind that gravel tires are wider (and hence taller) and the larger circumference of gravel tires makes the gear ratio taller. So unless you ride on flat gravel roads the GRX is the better choice. The other option is to fit the GRX crank to the new 12-speed. But thus far no one has tried it so we don’t know whether that works or not. It seems that the new 12-speed FD may take a large ring as small as a 46T. But shifting a chainring gap of 17T reliably is questionable.


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I do have a GRX 1x11, Cassete range is the same 11-34, the add'l teeth is appreciated as I like smaller gaps between gears
indeed the front 48-31 of the GRX is better than a 50-34 for gravel...., as you say, I wonder if ultegra would work fine on 48-31 and if not, keep the 50-34 in the front and go for something bigger in the rear... although not sure about the options for 12 speed and compatibility with ultegra rear derailleur

Loukas
Posts: 16
Joined: Thu Dec 24, 2020 6:28 pm

by Loukas

ooo wrote:
Mon Jan 03, 2022 2:37 pm
grx on the front have more gear range
grx on the rear have option to ride standard range RD with 1x/2x and wide range RD with 1x/2x
you can use grx shifter st-rx815 with new calipers br-r8170/br-r9270 for extra clearance
like the idea of the new calipers br-r8170/br-r9270 for extra clearance as I currently get some disc rubbing with my GRX calipers

ooo
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by ooo

Ultegra FD-R8150 vs Sram Red Quarq 46-33T crankset noise:

'

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pdlpsher1
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Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

ooo wrote:
Mon Jan 03, 2022 9:08 pm
Ultegra FD-R8150 vs Sram Red Quarq 46-33T crankset noise:
Thanks for sharing. I don't hear any noises. That FD shift is fast! The FD looks to be very high but the shifting appears to be good. Do you agree? There's hope that the 12-speed FD would work with the GRX 48-31. If you find a video of such combo please share it here. Thanks.

ps Ok, I hear FD rubbing noise on the big-big and small-small combos. But realistically those gear combos are never used.
Last edited by pdlpsher1 on Tue Jan 04, 2022 3:40 am, edited 2 times in total.

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pdlpsher1
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Location: CO

by pdlpsher1

Loukas wrote:
Mon Jan 03, 2022 6:34 pm
pdlpsher1 wrote:
Mon Jan 03, 2022 12:48 pm
Do you currently have a gravel bike? If so what gearing do you have on it? The most obvious difference between the two groups is gearing. The max low gearing on the Ultegra is 1:1. That’s not low enough for serious gravel rides. Keep in mind that gravel tires are wider (and hence taller) and the larger circumference of gravel tires makes the gear ratio taller. So unless you ride on flat gravel roads the GRX is the better choice. The other option is to fit the GRX crank to the new 12-speed. But thus far no one has tried it so we don’t know whether that works or not. It seems that the new 12-speed FD may take a large ring as small as a 46T. But shifting a chainring gap of 17T reliably is questionable.


Sent from my iPhone using Tapatalk
I do have a GRX 1x11, Cassete range is the same 11-34, the add'l teeth is appreciated as I like smaller gaps between gears
indeed the front 48-31 of the GRX is better than a 50-34 for gravel...., as you say, I wonder if ultegra would work fine on 48-31 and if not, keep the 50-34 in the front and go for something bigger in the rear... although not sure about the options for 12 speed and compatibility with ultegra rear derailleur
The 12-speed 11-34 has small gaps on the higher gears and I don't think the gearing is optimized for gravel. The 11-speed 11-34 has two tooth gaps on the higher gears but also two tooth gaps in the middle range of the cassette, which is perfect for gravel terrain. If you do use the 12-speed 11-34 for gravel you may find yourself annoyed by the 21-24 and 24-27 shifts. Assuming you have the Shimano 11-34 you're currently seeing 19-21-23-25-27 which is awesome for gravel terrain. The Rotor 11-36 has the same ratios as the Shimano 12-speed 11-34 except the two largest cogs, and it appears to be more for road with a 36 bailout gear. If you wish to give it a try on the 12-speed with GRX crank I'm all for it. I'm already using the GRX crank on my road bike. Once I know it works with the 12-speed FD I'll do the upgrade.

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jokerpt50
Posts: 6
Joined: Wed Jan 29, 2020 2:47 am

by jokerpt50

I have a new allied echo I ordered with new ultegra 12spd and plan on using my Easton ec90sl crankset but cant decide what chainring to run it with (50/34) or 47/32 which I run on my no22 now. I ride 75% roadie and like the current setup but it has had dropped chains due to my mechanical ultegra derailleurs not lining up perfectly. Will it be okay with newer di2 setup or should i just get the road chainring size. Anyone have experience with this to bump the OP's question would be great to know.

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