Go Back  Bike Forums > Bike Forums > Cyclocross and Gravelbiking (Recreational)
Reload this Page >

Thoughts on 2x11 vs 2x12 drivetrains?

Notices
Cyclocross and Gravelbiking (Recreational) This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like : "Unbound Gravel". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

Thoughts on 2x11 vs 2x12 drivetrains?

Old 05-30-24, 01:04 PM
  #1  
Newbie
Thread Starter
 
Join Date: May 2024
Posts: 13
Liked 0 Times in 0 Posts
Thoughts on 2x11 vs 2x12 drivetrains?

I'm considering upgrading my Shimano 105 groupset to mechanical GRX, particularly GRX810. However, I'm not sure if I should opt for 11 speed or 12 speed rear derailleur/cassette/shifters. My considerations are price, potential future upgrades to Di2, and long-term availability of replacement components and support.

Is Shimano likely to continue producing 11 speed parts, or is there a trend towards 12 speed?

Thanks!
puppychow is offline  
Old 05-30-24, 01:20 PM
  #2  
Senior Member
 
Join Date: Sep 2017
Posts: 8,354
Liked 11,663 Times in 4,977 Posts
Originally Posted by puppychow
Is Shimano likely to continue producing 11 speed parts, or is there a trend towards 12 speed?
Yes, and yes.
Koyote is offline  
Old 05-30-24, 01:58 PM
  #3  
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 4,010

Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3

Liked 1,632 Times in 1,119 Posts
GRX RD-RX810 (2x11) officially supports up to an 11-34 cassette:
SHIMANO GRX Rear Derailleur 11-speed (34T max low sprocket) | SHIMANO BIKE-US
And many are apparently able to run an 11-40 cassette merely with a B-screw adjustment.

GRX RD-RX820 (2x12) officially supports up to an 11-36 cassette:
SHIMANO GRX - Rear Derailleur - SHIMANO SHADOW RD+ 12-speed | SHIMANO BIKE-EU
The smallest Shimano 12-speed MTB cassette is a Micro Spline 10-45; not sure if this combination would work together.

So it depends on the gearing you need, which in turn depends on the terrain you ride.
SoSmellyAir is offline  
Likes For SoSmellyAir:
Old 06-02-24, 06:09 AM
  #4  
Newbie
Thread Starter
 
Join Date: May 2024
Posts: 13
Liked 0 Times in 0 Posts
Cool thank you for the advice! Sounds like the 12 speed enables a larger/easier gear
puppychow is offline  
Old 06-02-24, 07:58 AM
  #5  
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 4,010

Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3

Liked 1,632 Times in 1,119 Posts
Originally Posted by puppychow
Cool thank you for the advice! Sounds like the 12 speed enables a larger/easier gear
Yes, but only if you go by the official specifications. In actual practice, GRX RD-RX810 (2x11) works with an 11-40 cassette, whereas it is currently unknown whether GRX RD-RX820 (2x12) would work with a 12-speed MTB cassette.
SoSmellyAir is offline  
Old 06-02-24, 05:15 PM
  #6  
Junior Member
 
bald1der's Avatar
 
Join Date: May 2021
Location: North Carolina
Posts: 122

Bikes: Cannondale Quick CX3, Topstone Carbon 3L

Liked 77 Times in 43 Posts
Depends on the 2X 12 you go with you may be limited. I have been looking at getting a Cannondale Topstone 1. My LBS has last years model on the floor it’s running a GRX 2X 11 46/30 Crank and 11-34 Cassette, and the New model runs a GRX 2X12 speed. Same specs front and rear and from what I’ve been reading you can only go up to a 11-36 rear cassette and it’s not running a micro spline, If your wanting to run different specs you might have to change to a micro spline rear hub.
bald1der is offline  
Old 06-02-24, 07:12 PM
  #7  
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 4,010

Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3

Liked 1,632 Times in 1,119 Posts
Originally Posted by bald1der
Depends on the 2X 12 you go with you may be limited. I have been looking at getting a Cannondale Topstone 1. My LBS has last years model on the floor itís running a GRX 2X 11 46/30 Crank and 11-34 Cassette, and the New model runs a GRX 2X12 speed. Same specs front and rear and from what Iíve been reading you can only go up to a 11-36 rear cassette and itís not running a micro spline, If your wanting to run different specs you might have to change to a micro spline rear hub.
Even if one was willing to change to a Micro Spline freehub, it might still be too much to ask an RD rated for a 36T max cog to shift onto a 45T cog.
SoSmellyAir is offline  
Likes For SoSmellyAir:
Old 06-02-24, 08:41 PM
  #8  
Senior Member
 
Join Date: Dec 2020
Location: Los Angeles
Posts: 961
Liked 1,107 Times in 465 Posts
The Shimao 11 (non existent) and 12 speed 11-36t cassettes don't seem all that great. I'm running a 10 speed GRX400 shifters with an a 10 speed 11-36t XT 10 speed cassette. I find this cassette to be excellent with smooth shifts and it's fairly lightweight. I'm disappointed Shimano didn't try doing an Ultegra/XT level 12 speed 11-36t cassette.

I'm mostly using my low gears anyways, so 2x10 isn't an issue for me on gravel. I also have 2x11/12 speed road bikes, and I have no problem switching between the different drivetrains.
jonathanf2 is offline  
Old 06-11-24, 03:26 PM
  #9  
Senior Member
 
50PlusCycling's Avatar
 
Join Date: Mar 2018
Posts: 1,239
Liked 944 Times in 471 Posts
I run a 1x12 GRX driveline, and like it. It has lots of range, and shifts very well. The 2x system would shift better as there is less variation in the big rings on the cassette. Pushing the chain onto the 51t ring on my current cassette isn’t as smooth as the lower gears.

I’m rather disappointed that Shimano’s new Di2 GRX kit isn’t available in a 1x setup, and can’t be used with my 51t cassette. However, I think I can use the new 12 speed shifter with an XTR Di2 SGS derailleur, as I have had success mixing and matching road and MTB parts in previous bike builds.
50PlusCycling is offline  
Old 06-11-24, 09:37 PM
  #10  
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 4,010

Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3

Liked 1,632 Times in 1,119 Posts
Originally Posted by jonathanf2
I'm mostly using my low gears anyways, so 2x10 isn't an issue for me on gravel. I also have 2x11/12 speed road bikes, and I have no problem switching between the different drivetrains.
I am on 2x11 on both road and gravel. Right after I bought my gravel bike, I used to think that my road gearing would somehow influence my gravel gearing, but the diameter and weight of the tires are so different between the two setups that there is little to no correlation between their respective gearing.
SoSmellyAir is offline  
Old 06-12-24, 11:56 AM
  #11  
Senior Member
 
Join Date: Dec 2020
Location: Los Angeles
Posts: 961
Liked 1,107 Times in 465 Posts
Originally Posted by SoSmellyAir
I am on 2x11 on both road and gravel. Right after I bought my gravel bike, I used to think that my road gearing would somehow influence my gravel gearing, but the diameter and weight of the tires are so different between the two setups that there is little to no correlation between their respective gearing.
I think Shimano underestimated the needs of gravel gearing with 11 speed. They didn't bother to release an 11-36t for 2x and were quite conservative with an in-spec 42t max for 1x. My issue with current gravel gearing is that I'd prefer not to have bigger cassettes or more cogs, but I would rather have smaller chainring options. Something like a 42-26t would be perfect for SoCal terrain. Especially with urban flat stretches and mountainous trail regions. 46-30t is okay, but with summer on the horizon, that lower gearing can help reduce fatigue on long climbs.
jonathanf2 is offline  
Old 06-12-24, 12:20 PM
  #12  
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 4,010

Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3

Liked 1,632 Times in 1,119 Posts
Originally Posted by jonathanf2
I think Shimano underestimated the needs of gravel gearing with 11 speed. They didn't bother to release an 11-36t for 2x and were quite conservative with an in-spec 42t max for 1x. My issue with current gravel gearing is that I'd prefer not to have bigger cassettes or more cogs, but I would rather have smaller chainring options. Something like a 42-26t would be perfect for SoCal terrain. Especially with urban flat stretches and mountainous trail regions. 46-30t is okay, but with summer on the horizon, that lower gearing can help reduce fatigue on long climbs.
SHIMANO 11-Speed 11-34T Road Cassette Sprocket | SHIMANO BIKE-EU
SHIMANO DEORE XT 11-Speed MTB Cassette Sprocket | SHIMANO BIKE-EU

CS-HG800-11 (335 g): 11 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 27 | 30 | 34
CS-M8000 XT (411 g): 11 | 13 | 15 | 17 | 19 | 21 | 24 | 27 | 31 | 35 | 40

Why the reluctance to use an XT 11-40 cassette if you want lower gearing? Only a < 100 g overall difference (76 g for bigger cassette + extra chain links).

GRX 46 | 30 chain rings are the lowest official option. I would consider these if and when my GRX 48 | 31 chain rings wear out. A 42T big chain ring with an 11T smallest cog would be slightly too low for any downhill paved portion.
SoSmellyAir is offline  
Old 06-12-24, 02:55 PM
  #13  
Senior Member
 
Join Date: Dec 2020
Location: Los Angeles
Posts: 961
Liked 1,107 Times in 465 Posts
Originally Posted by SoSmellyAir
SHIMANO 11-Speed 11-34T Road Cassette Sprocket | SHIMANO BIKE-EU
SHIMANO DEORE XT 11-Speed MTB Cassette Sprocket | SHIMANO BIKE-EU

CS-HG800-11 (335 g): 11 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 27 | 30 | 34
CS-M8000 XT (411 g): 11 | 13 | 15 | 17 | 19 | 21 | 24 | 27 | 31 | 35 | 40

Why the reluctance to use an XT 11-40 cassette if you want lower gearing? Only a < 100 g overall difference (76 g for bigger cassette + extra chain links).

GRX 46 | 30 chain rings are the lowest official option. I would consider these if and when my GRX 48 | 31 chain rings wear out. A 42T big chain ring with an 11T smallest cog would be slightly too low for any downhill paved portion.
I've tried an 11-40t cassette on both the GRX400 and Ultegra RX800 RDs and I feel shifting is a bit sloppy at the small cogs. B screw will clear without an extender, but I didn't care for it. At least with my current 11-36t cassette, shifting feels precise.
jonathanf2 is offline  
Old 06-12-24, 03:31 PM
  #14  
Senior Member
 
Join Date: Jun 2015
Location: North Central Wisconsin
Posts: 4,743
Liked 1,236 Times in 802 Posts
Originally Posted by SoSmellyAir
In actual practice, GRX RD-RX810 (2x11) works with an 11-40 cassette


Have you tested this or know someone that has? Shimano website says 34T max.

I'm currently running 11-34 with 2x on my gravel rig and wouldn't mind a little bit lower gear if this actually works.
prj71 is offline  
Old 06-12-24, 05:48 PM
  #15  
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 4,010

Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3

Liked 1,632 Times in 1,119 Posts
Originally Posted by jonathanf2
I've tried an 11-40t cassette on both the GRX400 and Ultegra RX800 RDs and I feel shifting is a bit sloppy at the small cogs. B screw will clear without an extender, but I didn't care for it. At least with my current 11-36t cassette, shifting feels precise.
I see. I have a GRX RD-RX810.

Originally Posted by prj71
Have you tested this or know someone that has? Shimano website says 34T max.

I'm currently running 11-34 with 2x on my gravel rig and wouldn't mind a little bit lower gear if this actually works.
These guys told me about running an 11-40 cassette. Expanded Range GRX - Bike Forums

See particularly the material cited in post #6. I have not tried it yet.
SoSmellyAir is offline  
Old 06-15-24, 01:15 PM
  #16  
Senior Member
 
Join Date: May 2018
Location: Fargo ND
Posts: 954

Bikes: Time Scylon, Lynskey R350, Ritchey Breakaway, Ritchey Double Switchback, Lynskey Ridgeline, ICAN Fatbike

Liked 581 Times in 330 Posts
I have been very happy with my Ekar 1X13 gearing, and as a bonus I get Campagnolo / Magura brakes. Granted, my "gravel" bike does a lot more miles on packed snow and ice than gravel.

It has the advantage of having very low gears for rough going, along with high enough gears at the top end to allow me to pedal up to 35 MPH. Also, having a wide ratio low gear range and a close ratio high range works very well for me.
DangerousDanR is offline  
Old 06-20-24, 05:45 AM
  #17  
Senior Member
 
sean.hwy's Avatar
 
Join Date: Jan 2020
Location: Sacramento
Posts: 1,051

Bikes: Ibis Hakka MX / team machince alr2 / topstone 1 / Cervelo zht

Liked 278 Times in 204 Posts
Originally Posted by prj71
Have you tested this or know someone that has? Shimano website says 34T max.

I'm currently running 11-34 with 2x on my gravel rig and wouldn't mind a little bit lower gear if this actually works.
I have been running the grx 2x with the cassette at 11-40T for years. It's well documented.

Low Geared Gravel Bike


sean.hwy is offline  
Likes For sean.hwy:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Your Privacy Choices -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.