Go Back  Bike Forums > Bike Forums > Tandem Cycling
Reload this Page >

Shimano grx groupset

Notices
Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

Shimano grx groupset

Old 06-23-19, 07:17 PM
  #1  
ahultin
Senior Member
Thread Starter
 
ahultin's Avatar
 
Join Date: May 2007
Location: Bonsall, Ca
Posts: 625

Bikes: 2003 Cannondale Jekyll 1000, 2014 Fuji Finest 1.5 (wife), 2008 Fuji Finest 1.0 (Daughter), 2012 Fuji Cross 2.0 (son), 2011 Cannondale Road Tandem 2

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Likes: 0
Liked 7 Times in 7 Posts
Shimano grx groupset

I am looking at this groupset for a new co-motion steelhead that one of my stokers just ordered . The main advantage is the native support for up to a 42 tooth cassette. What I cant seem to locate is what post mount brake would be the best to use (flat mount is not yet an option for the steelhead). Does anyone know, Would the new xt 2 or 4 piston post mount brakes work ?
ahultin is offline  
Old 06-24-19, 08:52 AM
  #2  
OneIsAllYouNeed
Long-term wear tester
 
Join Date: Dec 2006
Location: Seacoast, NH
Posts: 752

Bikes: Cycles Chinook travel/gravel/family tandem, KHS CX200 road/gravel, Voodoo Agwe fixie commuter, Gunnar Sport travel/road, Motobecane Boris fatbike

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 232 Post(s)
Liked 30 Times in 22 Posts
The GRX rear derailleurs aren't much different from other current offerings from Shimano and SRAM. They have a 1X version (with limited chainwrap) for 42T cogs or a 2X version for 34T cogs. The Shimano RD-M8000 (plus WolfTooth Tanpan) and SRAM GX (plus WolfTooth Roadlink) remain much better derailleurs for wide range drivetrains.

To the original question -- yes, you can mix Shimano road hydraulic levers with Shimano MTB hydraulic brakes and vice versa.
OneIsAllYouNeed is offline  
Old 06-24-19, 12:47 PM
  #3  
ahultin
Senior Member
Thread Starter
 
ahultin's Avatar
 
Join Date: May 2007
Location: Bonsall, Ca
Posts: 625

Bikes: 2003 Cannondale Jekyll 1000, 2014 Fuji Finest 1.5 (wife), 2008 Fuji Finest 1.0 (Daughter), 2012 Fuji Cross 2.0 (son), 2011 Cannondale Road Tandem 2

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Likes: 0
Liked 7 Times in 7 Posts
Originally Posted by OneIsAllYouNeed View Post
The GRX rear derailleurs aren't much different from other current offerings from Shimano and SRAM. They have a 1X version (with limited chainwrap) for 42T cogs or a 2X version for 34T cogs. The Shimano RD-M8000 (plus WolfTooth Tanpan) and SRAM GX (plus WolfTooth Roadlink) remain much better derailleurs for wide range drivetrains.

To the original question -- yes, you can mix Shimano road hydraulic levers with Shimano MTB hydraulic brakes and vice versa.
Thank you! I completely missed the reduced chain wrap in the specs and thought it was just a long cage and short cage version.
ahultin is offline  
Old 06-30-19, 02:54 PM
  #4  
Chris_W
Likes to Ride Far
 
Chris_W's Avatar
 
Join Date: May 2007
Location: Switzerland
Posts: 2,323

Bikes: road+, gravel, commuter/tourer, tandem, e-cargo, folder, CAR-FREE

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 30 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
I'm also interested in the new GRX group and had noticed the two derailleurs offered. Does anyone know if the "1x" version of the GRX derailleur really is limited to use on single chainrings, like SRAM's 1x derailleurs are? I'm running a 40 or 42 tooth cassette PLUS a double chainring to get the gear range that I want without any excessive gaps between ratios. Shimano MTB or any SRAM derailleurs are not options because I'm using Di2 and the FD needs to have a braze-on mount.

So, should I go with the GRX derailleur that officially gets low enough to clear the 42-tooth cog, or go with the version that is officially listed for double chainrings and hope that it can drop down low enough? Chain wrap capacity isn't so important since the Di2 sensibly blocks access to the small-small gear combos anyway. Thanks.
Chris_W is offline  
Old 06-30-19, 02:59 PM
  #5  
Darth Lefty 
Disco Infiltrator
 
Darth Lefty's Avatar
 
Join Date: May 2013
Location: Folsom CA
Posts: 12,198

Bikes: Stormchaser, Paramount, Timberjack, Expert TG, Samba tandem

Mentioned: 67 Post(s)
Tagged: 0 Thread(s)
Quoted: 2445 Post(s)
Liked 1,219 Times in 790 Posts
I think that you are going to see longer cages for these derailleurs just like we used to with the 10 speed MTB derailleurs.
Darth Lefty is online now  
Old 07-05-19, 09:55 PM
  #6  
sch
Senior Member
 
Join Date: May 2003
Location: Mountain Brook. AL
Posts: 3,912
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 279 Post(s)
Likes: 0
Liked 94 Times in 75 Posts
If Shimano is true to form, the GRX group stuff probably won't be available on the retail side until late fall,
maybe even early next spring. I got all hot and bothered about the Ultegra 8000, announced in April-May but
could not find any for sale on the web til Jan-feb of the following year. Ditto with the following year 105
7000 group. Annoyingly, a few months ago I finished re-uping a 2001 frame to a 7000 group but had to
use an FSA chainset to get the desired 48-32 at a reasonable price. Now GRX comes out with such......... Maybe in 3-4 yrs, when
the FSA gets long in the tooth and worn..... At least Shimano is finally making sub/sub compact CW sets.
By that time the 46/30 might be more attractive.
sch is offline  
Old 07-08-19, 12:18 AM
  #7  
Chris_W
Likes to Ride Far
 
Chris_W's Avatar
 
Join Date: May 2007
Location: Switzerland
Posts: 2,323

Bikes: road+, gravel, commuter/tourer, tandem, e-cargo, folder, CAR-FREE

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 30 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
Regarding availability, at least some of the GRX cranks are already available - I received two 46-30 cranks in June that I ordered from the local importer as soon as they were announced back in April. Availability for the mechanical derailleurs is listed as July/August and the Di2 versions for September. I have a bunch of parts back-ordered to go on various bikes, so we'll see when they all arrive. Many bike brands have gravel bikes with full GRX groups listed in their 2020 lineups that should be available this fall/autumn.

BTW, the standard Ultegra Di2 front derailleur works perfectly on the new 46-30 cranks, despite the chainline being slightly wider than the derailleur was designed for and the teeth of the big ring being slightly lower. Making the necessary adjustments was no problem on two separate bikes that both have braze-on FD mounts.
Chris_W is offline  
Old 07-18-19, 11:11 AM
  #8  
sch
Senior Member
 
Join Date: May 2003
Location: Mountain Brook. AL
Posts: 3,912
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 279 Post(s)
Likes: 0
Liked 94 Times in 75 Posts
That is interesting but I note you are in Switzerland. Just quoting my experience with the 8000 and then 7000 series Shimano groupsets
availability in the US and applying to the GRX. OTOH Shimano has pretty much cutoff European sourced sales to the US, at least the
3-4 UK outlets that had 105 to Di2 groupos for somewhat less than US pricing until ~6-8 months ago. The year the Ultegra 8000 Di2 was
announced ( in April) a friend getting a custom bike built had to wait to December to finally get his Di2 hydraulic shifters in that groupset.
Manufacturers get stuff a lot sooner than the retail channels. I would really have liked to have the GRX on my rebuild but it is too late.

A bit of google shows that Jensen in US has 46-30 GRX cranks in stock.... (...appropriate curse words...)!

Last edited by sch; 07-18-19 at 11:16 AM.
sch is offline  
Old 05-21-20, 02:20 AM
  #9  
cherz
Junior Member
 
Join Date: Jun 2013
Location: austria
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked 0 Times in 0 Posts
Originally Posted by Chris_W View Post
I'm also interested in the new GRX group and had noticed the two derailleurs offered. Does anyone know if the "1x" version of the GRX derailleur really is limited to use on single chainrings, like SRAM's 1x derailleurs are? I'm running a 40 or 42 tooth cassette PLUS a double chainring to get the gear range that I want without any excessive gaps between ratios. Shimano MTB or any SRAM derailleurs are not options because I'm using Di2 and the FD needs to have a braze-on mount.

So, should I go with the GRX derailleur that officially gets low enough to clear the 42-tooth cog, or go with the version that is officially listed for double chainrings and hope that it can drop down low enough? Chain wrap capacity isn't so important since the Di2 sensibly blocks access to the small-small gear combos anyway. Thanks.
did you find an answer to your question yet ?
cherz is offline  
Old 05-21-20, 12:45 PM
  #10  
Tom M
Senior Member
 
Tom M's Avatar
 
Join Date: Apr 2008
Location: Alexandria, VA
Posts: 54

Bikes: IRO Rob Roy SS, ~1979 Pogliaghi, 1991 Bob Jackson, 2014 Seven Axiom 007 Tandem

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
This is from Redkite Prayer (https://redkiteprayer.com/2020/05/shimano-grx/):
Shimano intends for the 2x crank to be used with the 11-34 cassette and the 1x version to be used with the 11-40 or 11-42 cassettes. That’s why two rear derailleurs. Now, I know people out there are wondering if mixing and matching is possible. Looking at the tech specs, I’m going to suggest that with a longer chain, a screwdriver at the B screw and some patience, I think you could get the 2x crank to work with the 1x rear derailleur and the 11-40 cassette (but not the 11-42), which would make for a pretty killer gravel setup for some of the terrain here in Northern California. Officially, Shimano won’t confirm this, but their stuff is so well engineered that as long as you aren’t prone to riding big/big, it could be a real knee saver.
The entire review is worth a read.
Tom
Tom M is offline  
Old 05-21-20, 02:04 PM
  #11  
Chris_W
Likes to Ride Far
 
Chris_W's Avatar
 
Join Date: May 2007
Location: Switzerland
Posts: 2,323

Bikes: road+, gravel, commuter/tourer, tandem, e-cargo, folder, CAR-FREE

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 30 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
Originally Posted by cherz View Post
did you find an answer to your question yet ?
I've setup the GRX 2x rear derailleur that's officially rated up to a 34 tooth cassette on a couple of bikes with a 40 tooth cassette without any problems - the upper cog can be adjusted low enough to clear the big cog and it stays close enough to the small cogs to give pretty crisp shifting. Maybe it won't work on some bikes with extra short derailleur hangers, but in general it should be OK. I haven't tried it with a 42-tooth cassette because the 30-40 combo is sufficient for me even when riding in Switzerlad.
Chris_W is offline  
Old 05-25-20, 04:54 AM
  #12  
bikeinxs
Senior Member
 
Join Date: May 2008
Location: Ottawa, Canada
Posts: 146

Bikes: Ibis Cousin It converted to a drop bar dirt road cruiser, True North Ti Tandem, garage full of half bikes

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked 10 Times in 3 Posts
I put the Di2 GRX group on a single bike last fall and I really like it. Unfortunately our tandem was all built up before GRX became available. Having said that, I'm not sure I'd be happy with a 48 tooth big ring on the tandem and it turns out we can run an 11-42 cassette with our Ultegra rear derailleur. It all depends on the geometry of your derailleur hangar.

Also, GRX chainrings use a different bolt pattern. Not sure they would work with any current tandem cranksets.
bikeinxs is offline  
Old 05-25-20, 11:00 AM
  #13  
tandem rider
Senior Member
 
Join Date: Dec 2005
Location: Indianapolis, IN
Posts: 400

Bikes: Co-Motion tandem, Serotta, and Specialized mt. bike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked 11 Times in 11 Posts
I had Di2 Ultegra with 50-34 on front and 11-34 cassette (11 speed), fall 2018 before GRX. I wanted Di2 and it was the lowest gearing I could get on a new tandem. With a team age of 138, it was geared too high for steep hills in southern Indiana. On flats with wind or in rolling hills the front derailleur was frequently shifting between chainrings. Last July, my wife and I took the tandem to Tandems East. They replaced the cranksets with an FSA triple and Di2, XTR derailleurs to change our gearing to 52-39-30 and 11 speed with up to 11-42 Sram cassette. We chose the 11-36 which is enough gearing for us and keeps the jumps closer together. The FSA crankset also reduced the q-factor. Tandems East used our original shifter, battery, and had the original Di2 "brains" reprogramed to work. We choice to have the XTR Di2 "brain" put on as it is easier for me to use. It briefly shows what gear I am in, the charge left in the battery, and if in manual, semi-synchro or synchro shifting. The cost, and trip from Indy to New Jersey were well worth it, we are much happier with this crankset, and gearing.
tandem rider is offline  
Likes For tandem rider:
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
metalheart44
Bicycle Mechanics
1
03-04-18 03:12 PM
vinuneuro
Cyclocross and Gravelbiking (Recreational)
8
01-17-18 07:13 PM
Darth Lefty
Mountain Biking
15
03-25-16 06:55 PM
Ritterview
Tandem Cycling
42
10-26-15 08:17 AM
nakos2000
Mountain Biking
5
04-09-15 11:03 PM

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.