GRX Technical Documents
 

Shimano has published technical documents for the GRX line

https://si.shimano.com

Not earth shattering news but melacholic analytics like me find it interesting and I'm seeing the components available for pre-order with ETA 6/15/19.

https://cimg0.ibsrv.net/gimg/bikefor...ff4baae2c9.jpg

-Tim-

Thanks.

BTW it is "melancholic."

I believe that JensonUSA has GRX parts available for pre-order.

You have ruined my week.


-Tim-

Have you ever done a Shimano pre-order on a newly-introduced groupset? I have. My most recent was Ultegra Di2 disk. It once had a June ETA. Then it was August. Then late August. Then September. Then November. Then late November. Then December. Then the next February. Then . . . in February, I could get everything except the brifters and brakes. But I could get Dura Ace Di2 brifters and brakes, so I dug deep and paid myself out of my misery. If I had waited a couple more months, I could have had the whole groupset in Ultegra. 10 months after the original ETA. (And my new frameset sat in the LBS's storage for all those months.)

Adding to the frustration was that OEM bikes with the groupset installed were readily available for most of that time. Individuals don't get the goods until the OEM pipeline is full.

I hope it's different this time. But every Shimano new-intro groupset I've ever pre-ordered became a very, very long wait with lots of ludicrous ETA's. Don't believe the ETA until your LBS tells you the groupset has arrived and after you've had a chance to inventory the goods. Until then, it's just wishful thinking. (Don't sell your old stuff yet.)

Hey, if I can succeed in making only one more person miserable ...

They and a few others have this pre-loaded on the website, but say 2 or 3 weeks for delivery. Supposedly some of the stuff is available today.

Shimano has prioritized local shops for availability of new slx, xt, and grx. My local shop got all 3 in on Friday. I am waiting on drivetrain only XT which comes in next month to upgrade by XC bike.

Wait, so it is actual hardware on the street for purchase, not vaporware?


-Tim-

Yes but full entire group only. Individual parts is not until end of July for XT/SLX and August for GRX.

I don't want to start a new thread on this, so I figured I would continue this one.

Why does the Tiagra level RD RX400 have more capacity (41T) and a better max low gear (36T) capability than the higher level RD RX810? I would love the capability of a 46/30 crankset paired to a 11-36 cassette, but I feel a little weird removing an Ultegra RD 6800 GS & replacing it with a Tiagra level RD. To add insult to injury, I don't believe the newer 11 speed Shimano stuff is compatible with the 10 speed and lower stuff, but I could be wrong. I like that Shimano finally released this stuff, but this seems a little backwards.

I currently have a 46/30 crankset and 11-36 cassette with an ordinary Ultegra RD (the Di2 mid-cage derailleur that corresponds to the 6800 series). Why not try just the crank and/or 11-36T (or 11-34T Shimano) cassette first?

That setup leads to a 41T difference, which exceeds the 37T capacity of the 6800 GS. While Shimano is known to be conservative on the low gear for the cassette, it is my understanding that their capacity listing for the derailleur is spot on. While riding on surfaces other than tarmac I am usually utilizing the inner chainring. This, with the higher gearing cogs on the cassette, would lead to a loose chain condition, chain slap, & possibly worse. IMO, saying this is not ideal is being nice.

I have an HG-800 (11-34, 11 speed) cassette on the way. With my 46/32 crankset, this will max out my derailleur capacity.

Is GS the mid-cage or short-cage? If it is the mid-cage, it will work fine. (I didn't even know about the 37T difference capacity.) (Just looked it up, I see that it is.) Several of us here have this kind of setup. It works fine. (I have one wheelset with a SRAM 11-36T and one with Shimano's newer 11-34T cassette. Both shift without issue.)

Shimano says the 41T capacity RDs are for 1x systems.

RD-RX400 SHIMANO SHADOW RD+

• Similar stabilizer technology and design as premium GRX series
• Compatible with existing Shimano mechanical 10-speed road ST
• Max. cassette range: 36-30T low)
• Max. front chainring range: 16T
• 41T capacity
• 303 g

This one shows a 16T chainring range for the crankset. I believe Shimano is resisting the dedicated 1x systems. In addition that that, who would by a 1x system with a 36T max low cassette limitation? Finally, a 1x system with a maximum of a 36T cassette & a 41T capacity would give you a -5T high gear.

Depending on where I am riding, ME!!!!!

the only thing better than a 42T paired to a 11-36 would be making it Electronic.

Just as a general non-scientific observation, higher end components are seen as "racier" so tend not to support the lowest gearing or widest gear range, especially if that allows the designers to save weight or get faster shifting. You also see this in Dura-Ace vs Ultegra. I don't think the current Dura-Ace RD supports 11-34 cassettes, for example (max is 11-30).

The pulley cage is longer and heavier and arguably less aesthetic. That's basically why DA never got the long(mid) cage rds

Derp, I got my parts confused. Saw 41T capacity and thought of RX812. Too many damn GRX parts.

You are correct. I forget that not everyone lives where I do. The majority of the time my gravel bike's chain is wrapped around a 46T chainring. However, when it comes to long & steep gravel hills, I much prefer gear ratio below 1:1. For me, a gravel bike should have both mountain bike gearing and road gearing, which lead to my excitement of an RD with a 41T capacity and the ability to easily run an 11-36 cassette.

Running an 11-36 cassete is nothing new, I dot it just fine on my Ultegra RX rear derailleur with an SLX 10 speed mountain bike cassete and RS405 10 speed hydraulic shifters, and I used to run the same system with a Tiagra 4700 rear derailleur. What I personly would like to be able to run an 11-42 mountain bike cassete with a 46-30 crankset, the same low 30x42 gear I have on my XC bike for the steep stuff and a 46x11 for the faster sections. I know people have been doing it with the ultegra RX rear derailleur but seems like quite a lot for the RD,

Shouldn't be a problem. I'm running the RX800 RD with a 50/34 11-40 and can use all the gears with a bit of capacity still
https://cimg3.ibsrv.net/gimg/bikefor...5fbbd8654c.jpg