Widest 2X Gearing for SRAM AXS or Shimano Di2

Gasman wrote:What calipers are you using with the GRX Di2 shifters (Im wondering if all I need is the new Di2 shifters and derailures?  Did you swap the long cage yourself and if so any thoughts, lessons learned (i.e. is it hard for a non-mechanic?!!).

I did swap the cage myself.  If you are mechanically inclined you can do it.  There are some YouTube videos out there too.  The big trick is you have to get the spring back in the right hole (there are two) and you have to tension (wind the spring) the right amount or it will not work.  You CAN put it together wrong, but it should be obvious.  There will be almost no tension on the chain.  Here's a thread on MTBr.com where we talked about this:  https://www.mtbr.com/threads/711-range-2x-crankset-and-11-51-cassette-gravel-bike.1209452/#post-15740191

You will also probably need larger pulleys.  I outlined all of this in that thread.

If you get into this and it gets gnarly, you can pm me there.  I don't have notifications on for here and don't post here a ton.  Saw your post in the monthly roundup email.

You can find screaming deals on XT F/R derailleurs, as they are not the hot ticket any more.  I paid $60 for my FD.  The XT8000 SGS cage can be hard to find in stock.  I found mine on eBay.  Or you can buy a used RD. 

As you can imagine, this is WAY outside any compatibility claimed by Shimano and I make no guarantees it'll work on every variation of bike out there.  Everything needs to be just about dead nuts on.  Not a lot of forgiveness...  so B-Screw adjustment, chain length....   everything needs to be right.  But this works very, very well for me.  It's Dr. Jekyll and Mr. Hyde.  2 1x drivetrains on the same bike.

If you simply cannot get the 11-51 to work, I have set up several bike with a Sunrace 11-46 and it is more forgiving and still gives a ton of range.

Gasman wrote:You paid $60 for a Di2 FD, where??  Im seeing about $290 per Di2 shifter, $110 front derailure at shops (Ive seen fakes on eBay) and $230 ish for RD.

One of the things that makes this work is the bigger pulleys and the fact that Di2 prevents you from shifting into the 3 smallest gears in the small ring, so you don't have to account for all that chain slack caused by chain long enough to accommodate the 51t.

Shimano Dura Ace 9070 di2 derailleurs. 

Rear derailleurs removable/replaceable jocky cage is cracked but works fine.

Shimano ST-R780 DI2 hydraulic levers

Shimano BR-RS785 HYDRAULIC CALIPERS

First thing you need to know is the the XT F & R D's need to be used as a set.  Or you can use DA or Ultegra or 105 F&R D's in this setup, but will probably be limited to 11-46.  I originally set this bike up with Ultegra levers and D's and ran up to 11-46 with no issues.  But you cannot mix and match road/gravel derailleurs with MTB derailleurs.  They have to be the same F&R or they will not operate.

The XT rear derailleur shifts much better on wide range cassettes due to the offset top pulley.

ALL of the derailleurs are compatible with road or gravel shifters.  Brakes will be fine either way.

ScottH wrote:Not as …w i d e… as mtbnut87 but I’m running GRX Di2 with 44/28 chain rings and 11-36 cassette. Could do a 11-40 cassette with b screw turned out or road link. I swapped out the rings on my GRX 48/31 crank with ones from Starbike.com. Work rather nicely. 

Gasman wrote:Was it as simple as pulling the cranks and removing the chainrings?  I looked for a slightly lower GRX rings and did not find them and am unfamiliar with Starbike.  Im enjoying trying to get to 16-120 gear-inches (my original goal was 20-12) which allows me to bike pack, run single track or road.  Unfortunalty right now the cost to go to Di2 is about what I have into the bike as is!

ScottH wrote:

Yes, it’s as easy as that. It’s around $100 total cost because shipping is like $35 to the USA. 

Gasman wrote:
How does it shift?

mtbnut87 wrote:

Interested as well.  How many shift ramps on the inside of the big ring?  Stock GRX only has 2 and that sometimes makes for very sluggish small to big shifts.

it has 4 ramps. There is a pin that gets screwed on, just make sure you use loctite. It shifts fine with no issues. Been using it for about 2 months so I can’t report anything on long term durability. 

ScottH wrote:

it has 4 ramps. There is a pin that gets screwed on, just make sure you use loctite. It shifts fine with no issues. Been using it for about 2 months so I can’t report anything on long term durability. 

Can you post a pic from the outside of the crank so I can see how it looks with the new rings mounted?

mtbnut87 wrote:
Well that's encouraging.  Thanks.  A set of these with the XT 11-46 will save me half a pound, shift better and have tighter spacing for road sections.  Might be a win-win-win.

 

Can you post a pic from the outside of the crank so I can see how it looks with the new rings mounted?

Looks pretty much the same as the GRX rings.  

This is with the GRX rings.

ScottH wrote:

This is with the GRX rings.