The Drivetrain Compatibility. Thread

moorey

I choo choo chose 29
Current-series R7000 105 and R8000 Ultegra (and GRX derivatives) in long form will fit up to 42T without goats, and have enough play for a narrowish-range 2x ringset.
I happened to be looking at a bike in Lbs while waiting. Was a gravel bike with GRX running a 42t. Noticed the hanger was longer and more horizontal than on my MTB’s (a bit more like a goat does). Wasn’t sure it it was just this bike or a thing that manufacturers are starting to do to better suit bigger cassettes.
 

ozzybmx

Níl aon tóin tinn mar do thóin tinn féin
Current-series R7000 105 and R8000 Ultegra (and GRX derivatives) in long form will fit up to 42T without goats, and have enough play for a narrowish-range 2x ringset.
Thats what I replaced it with a GRX RX812-R so I could run the 42T cassette and still have the right pull ratio from the 105 hydro shifters.
 

ozzybmx

Níl aon tóin tinn mar do thóin tinn féin
I happened to be looking at a bike in Lbs while waiting. Was a gravel bike with GRX running a 42t. Noticed the hanger was longer and more horizontal than on my MTB’s (a bit more like a goat does). Wasn’t sure it it was just this bike or a thing that manufacturers are starting to do to better suit bigger cassettes.
Not sure but there are 2 versions of 11spd, GRX810 (34t max) and GRX812 (42t max)

The GRX 812 fitted onto my 2011 IndyFab MTB frame and cleared the 42t easily.
 

leitch

Feelin' a bit rrranty
I happened to be looking at a bike in Lbs while waiting. Was a gravel bike with GRX running a 42t. Noticed the hanger was longer and more horizontal than on my MTB’s (a bit more like a goat does). Wasn’t sure it it was just this bike or a thing that manufacturers are starting to do to better suit bigger cassettes.
Sounds like a direct mount hanger.
 

ozzybmx

Níl aon tóin tinn mar do thóin tinn féin
The GRX derailleurs have a little extension/pivot on them that makes them sit back and down a bit compared to other Shimano mechs.

374642
 

leitch

Feelin' a bit rrranty
Made a point of making that stand out in special @HamboCairns pink.
Haha I picked that photo because it made it super obvious. I think they also come in @wkkie green.

"Shimano didn’t have much to say on the topic when I asked for an official statement, but team representatives I spoke with cited the claimed benefits: better shifting and faster wheel changes, the latter being especially critical on bikes equipped with disc brakes and thru-axles. It’s worth noting, too, that many of the Direct Mount hangers were conspicuously stout in their construction, with beefy cross-sections that would not only provide a firm foundation for precise shifts, but would likely be less prone to bending during a crash."

 

The Duckmeister

Has stumpy thumbs, Speciaized are so weird
Yeah it’s sort of moved from mtb to road for whatever reason. @The Duckmeister might have some insight into the justification.
Yeah, that B-Link isn't specific to GRX, it's common to all Shadow derailleurs from 9-11-sp, deletable for direct-mounting on most 10-sp. & all 11-sp. models.

The transfer of the Shadow design to road I think is largely due to the trend toward bigger cassettes; having a firm stopper against forward movement of the derailleur body really helps in setting and keeping suitable clearance under the bigger sprockets, where old flappy-pivot designs start mashing teeth and binding - the same advantages it brought to MTB when it appeared around '06-'07. The unwritten (at least officially) extra benefit is that there is enough adjustability to exceed the stated maximum sprocket by some margin (Shimano also have a habit of stating a given derailleur's maximum capacity based on the largest cassette on offer in that particular groupset...).

Direct-mount is good in concept because it removes a potential extra damage point (I've seen several bent B-Links, including one of my own), but its sticking point is that if frame manufacturers want to offer other drivetrain options with normal-mount derailleurs they either need two hangers, or simply don't adopt direct-mount. Most took the latter course, so Shimano quietly removed that capability with 12-sp.
 

Scotty675

Likes Bikes and Dirt
I swapped over to 12 speed short cage to try on 9-46 11 speed. I’ve sized an 11 speed chain for this.
374651

I did a comparison of cage length differences between 11 and 12 speed as well. I was surprised how much longer the one up and garbaruk cages were for 11 speed. In comparison to differences between 12 speed cage lengths. Last number mm
374652

Also a pic to show how they have grown in size from 11 speed. Larger jockey wheels
374653
 

Isaakk

Likes Dirt
That would be because they don't use grease on the roller clutch, as it makes the rollers stick & not engage properly. Oil is recommended from memory?
 
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