2024 Shimano RX825 2x12 GRX Di2

The spirit of Grav-lo-cross. No but seriously, cyclocross and gravel go here!

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satanas
Posts: 370
Joined: Sat Jul 04, 2020 5:45 pm

by satanas

Sorry, I really don't see 1x (= SRAM) as being the answer to everything.

It's also IMHO extremely unlikely that Wolftooth (or anyone else) will make aftermarket extended range 2x cages, for two reasons:

1. Wolftooth have made exactly zero 2x products
2. The GRX 820 cage is between 0-3mm shorter than the XT SGS cage; I bought a set of XT cage plates hoping they'd be significantly longer

I also can't see Shimano making any other 12 speed cassettes; the 5 we have now look like being it, versus at least 13 for 11 speed, and that's not counting CUES. :-(

If the 12 speed RDs are anything like the 11 speed ones then at least 42T with 2x should be fine; a few people even got away with 11-46 with 2x11.

As for larger 12 speed cassettes, there are a few, though not from Shimano:

1. Rotor 11-39/46
2. Sunshine/Goldix, etc 11-40/42/46 (Chinese)
3. Ingrid 11-44

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TobinHatesYou
Posts: 13046
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

satanas wrote:
Sat May 25, 2024 8:58 am
Sorry, I really don't see 1x (= SRAM) as being the answer to everything.

It's also IMHO extremely unlikely that Wolftooth (or anyone else) will make aftermarket extended range 2x cages, for two reasons:

1. Wolftooth have made exactly zero 2x products
2. The GRX 820 cage is between 0-3mm shorter than the XT SGS cage; I bought a set of XT cage plates hoping they'd be significantly longer

I also can't see Shimano making any other 12 speed cassettes; the 5 we have now look like being it, versus at least 13 for 11 speed, and that's not counting CUES. :-(

SRAM made a whole 1x subcategory for gravel and every major brand has chosen that for its highest-end builds, but Shimano can’t even be bothered. Shimano has four launch partners with Di2 2x12 GRX, and two of them are owned by the same parent company: Ventum, Litespeed/Obed, Mosaic. No Specialized, no Trek, no Giant, no Cervelo, etc. Seems those brands are all waiting on Di2 1x12…or Shimano hopes so.

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pdlpsher1
Posts: 4169
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

TobinHatesYou wrote:
Sat May 25, 2024 7:50 am
pdlpsher1 wrote:
Sat May 25, 2024 5:35 am

Here are the bikes of two of our local Cat1 gravel racers, Zack and Whitney Allison. Pic shown is Whitney's bike. Zack's Mog build is identical to Whitney's.
This is some serious survivor bias reasoning. 100% of sponsored GRX Di2 users are on 2x because that’s the only option they really have.

They were running 2x11-speed Di2 GRX until now, preferring it over 12-speed mechanical in either flavor. In other words they had to make a choice between electronic shifting and that 12th cog and chose the former. Without Di2, they clearly won’t choose 1x12 either especially when Shimano doesn’t have its own XPLR equivalent.

I think we’d get better insight looking into how the SRAM riders have sorted themselves. How many are on “2x Road Wide,” how many are on XPLR and how many are on mullet builds. Over here most self-spec SRAM dropbar dirt builds are mullet despite complete bikes from major brands predominantly being spec with XPLR, but west coast gravel is basically XC.
No. Let's bring up the elephant in the room. Shimano riders choose 2x because the superb front shifting Shimano has won't hold them back. Sram riders choose 1x because Sram's front shifting sucks. If Sram has as good of front shifting as Shimano more Sram riders will certainly choose 2x. James Huang even addressed this in the latest Geek Podcast- Sram can't get their front shifting to work as good as Shimano due to Shimano's patents. So they focused on options that don't use the FD.

BikeTyson
Posts: 693
Joined: Fri Oct 15, 2021 3:16 pm

by BikeTyson

pushpush wrote:
Fri May 24, 2024 6:01 pm
I live in a mountainous area. I regularly do climbs that are only just barely possible on a 34:51. I'm pretty strong. I need 2x and a big cassette to be able to climb fire roads and also be quick enough on the road.

The lack of support for mtb wide gearing seems like a huge miss.

I hate to say this. I swore this wouldnt happen. -- My next build might be sram even though I hate their brakes.
Woah, 34:51?!?!?! How do you not fall over? That's MTB gearing. I can't imagine pedaling that gear (I don't own a MTB). How steep are those climbs out of curiosity? Not questioning you gear choice I'm more just curious because that's crazy. I don't have anything close to that near me. I wouldn't be choosing those routes regularly.

BikeTyson
Posts: 693
Joined: Fri Oct 15, 2021 3:16 pm

by BikeTyson

TobinHatesYou wrote:
Fri May 24, 2024 9:59 pm
RDY wrote:
Fri May 24, 2024 1:48 pm
TobinHatesYou wrote:
Fri May 24, 2024 10:00 am
RDY wrote:
Thu May 23, 2024 5:55 pm
No official support for cassettes larger than 36T? That's unbelievably bad. They don't seem to want any of the 1x or wide range electronic 2x market.

Still, at least I can now pay €370 for 105 RD with clutch for road - €100 more than Ultegra.

36t on the low end would be okay if they just introduced Microspline Road and a 10t cog.

As for 1x, well we know the fully wireless, external battery MTB Di2 RD is coming.
Not really if you want to run a 50/34 and you're not either incredibly strong or light. A lot of people are running that with 11/40/42 and even up to 11/46 currently. No chance of the former as no casettes exist in that range for 12s (except Rotor - which supposedly only works with their transmission), and for the latter I think 11/44-46 will be beyond the capabilities of this RD.

I guess we can wait for WolfTooth to make a 2x compatible cage with up to 11-45. Since I can't imagine they won't do it. But it sucks that Shimano seem to be throwing in the towel on this.

Why would you run a 50/34x10-36 on gravel though? Hardly anyone needs 5:1 at the top end. 46/30x10-36 is equivalent to running 50/34x11-40 except you actually have extended range on both ends.
I run 52/35t and 11-36t for my gravel setup. And yes I use the 52-11 gearing. Every gravel ride and race I've ever done has tarmac sections where I'm using that gear. And more than once I've seen splits happen because people can't spin fast enough on low gearing to stay with the group. I'm not a huge fan of the 10t cog, but it would allow me to go down to a 48/31t crankset. Luckily I've never needed anything lower than 35-36. Anything much lower you're probably faster running anyway.

TobinHatesYou
Posts: 13046
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

pdlpsher1 wrote:
Sat May 25, 2024 9:58 am

No. Let's bring up the elephant in the room. Shimano riders choose 2x because the superb front shifting Shimano has won't hold them back. Sram riders choose 1x because Sram's front shifting sucks. If Sram has as good of front shifting as Shimano more Sram riders will certainly choose 2x. James Huang even addressed this in the latest Geek Podcast- Sram can't get their front shifting to work as good as Shimano due to Shimano's patents. So they focused on options that don't use the FD.

This doesn't explain why zero major brands and hardly any minor brands picked up 825.

RDY
Posts: 2587
Joined: Thu Jul 30, 2020 10:31 pm

by RDY

The reason is simple. It's a gravel groupset with a road cassette. Nobody's going to want that at the premium end.

Only informed demand I see for this is the RD (despite ridiculous price) to eliminate chain suck and drops on road, and hood shape preference / cheaper d-fly option than DA.

TobinHatesYou
Posts: 13046
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

RDY wrote:
Sat May 25, 2024 1:47 pm
The reason is simple. It's a gravel groupset with a road cassette. Nobody's going to want that at the premium end.

Only informed demand I see for this is the RD (despite ridiculous price) to eliminate chain suck and drops on road, and hood shape preference / cheaper d-fly option than DA.

Right, the market has spoken. Also bikes like the Diverge STR don't even support 2x.

RDY
Posts: 2587
Joined: Thu Jul 30, 2020 10:31 pm

by RDY

TobinHatesYou wrote:
Sat May 25, 2024 1:48 pm
RDY wrote:
Sat May 25, 2024 1:47 pm
The reason is simple. It's a gravel groupset with a road cassette. Nobody's going to want that at the premium end.

Only informed demand I see for this is the RD (despite ridiculous price) to eliminate chain suck and drops on road, and hood shape preference / cheaper d-fly option than DA.

Right, the market has spoken. Also bikes like the Diverge STR don't even support 2x.
The Diverge STR is a minute niche, and at least in Europe has sold horribly - dunno about the US. Rather more niche than gravel 2x.

abLEmiaB
Posts: 59
Joined: Wed Nov 16, 2022 5:40 am

by abLEmiaB

I will buy the new groupset. I have a Topstone frame waiting for it and as a first time gravel rider it suits my transition from road. It also allows me to standardise on 12 speed Di2 across 3 bikes.

satanas
Posts: 370
Joined: Sat Jul 04, 2020 5:45 pm

by satanas

IMO the 2x gearing options are a fail, unless the 11-34 cassette works for you. There are zero gravel races near me, but plenty of horrendously steep fire trail climbs that require extremely low gearing, particularly if bikepacking. Exactly none of the stock GRX options go low enough, even 1x, and with that there are horrible gaps; I'm a spinner and like to maintain a reasonably consistent cadence. As for 48x11 or 48x10, yeah I could use that on the road bike for fast descents (occasionally), but 48x10/11/12/13 are basically worthless to me with effectively 28+" OD tyres on dirt; YMMV.

The RD is indeed the crucial piece here, and with smaller than GRX chainwheels (plural), and most likely a >36T cassette there's some hope.

Also, I downloaded the revised dealer manuals last night and they seem to be missing a few things. Sigh. Hopefully Terry will do a GRX 825 Di2 cheat sheet soon, hint, hint.

RoadDonk82
Posts: 84
Joined: Wed Feb 08, 2023 2:43 pm

by RoadDonk82

IMO the 2x gearing options are a fail, unless the 11-34 cassette works for you
While I think your situation (someone fit but with very steep climbs) is quite rare and maybe they decide it's not worth catering to I do think it's surprising they don't offer smaller chain rings. If you are not a racer you will benefit from 46t-30t in front or even a 28t much more than from having 48-11 on high end. People use gravel bikes for bike packing, steep climbs, long days with some punchy climbs. A lot of them are far away from optimal weight or fitness. If you are not racing or very fit and wanting to pedal over 50km/h 46-11 or even 40-10 is plenty for a high gear. That's not what most people do on gravel bikes though. I think vast majority of gravel riders wouldn't care if they couldn't pedal above 45km/h.
SRAM kinda got it with their XPLR groupset but they wanted to make jumps not too big so the low gear is still only 40-44.
My first gravel bike had 46-30 in front (with 34t cassette) and I think 44-28 would be even better for someone who was quite out of shape back then (44-11 would be the same high gear as SRAM XPLR default option).

Anyway, I think it comes back to general observation that bikes are way over geared for general public both gravel and road bikes.
On local "adventure" group gravel bikes I've noticed a lot of people go mullet because of it and it's a shame there is no alternative.
I also think they are misreading their audience. Young fast guys don't have much money in aggregate. They are selling mainly to middle-aged people with a lot of disposable income who like to have nice things. That is especially true for high end options.
This doesn't explain why zero major brands and hardly any minor brands picked up 825.
Just guessing but maybe they have a lot of 11 speed GRX inventory to push before they offer the new one?

BikeTyson
Posts: 693
Joined: Fri Oct 15, 2021 3:16 pm

by BikeTyson

BikeTiresDirect has the new GRX stuff at 25% off this weekend. I went all in and ordered the group. The RD mainly for the clutch. 11-36t is more than enough for me, I've been fine on my current 11-34t but figured if I'm going 12sp I'd get the extra low gear. The levers I'm really interested in. The 11sp were a nice shape but the rubber ridges weren't very comfortable. The ridges look smaller now so we'll see. And the "hook" looks less pronounced so it should be a nice fit.

The pricing is kind of weird though.
GRX 12sp Di2 shifter/brake lever individual (no brakes): $280
GRX brake caliper (new version): $84
GRX 12sp Di2 shifter and brake caliper: $556

It's like a $200 premium for the set, which is just a hose included right? Either way, I got the levers for $210 each and already have 105 calipers.

plrww
Posts: 36
Joined: Sat Jan 02, 2021 2:21 pm
Location: Finland

by plrww

There would be a trivial solution to gearing for ordinary people if Shimano decided to make it: 3x. For example, 52-36-20 front and 11-36 rear. Small(ish) gaps between gears, wide 850 % range, cheap cassettes. I'd use the short gears every single day on steep gravel/tarmac ascents. Gravel bikes are also used on fast gravel rides with tarmac sections and in a group it is common to pull a group 50+ km/h on downhills. Roads are sometimes steep and you don't ride full gas every day. My W/kg is ½ of a pro so I need ½x gearing.

Gavin929
Posts: 79
Joined: Sun Nov 27, 2011 4:50 am

by Gavin929

Just installed the new GRX 825 rear derailleur on a build that is otherwise ultegra 8100. E-tube will not allow me to turn off the gear position control feature with the grx rear derailleur. I had previously been able to navigate around this on 9200 and 8100 di2 12 speed. Looks like its a hard no with the grx. Please let me know if anyone has a workaround. I don't usually cross chain but hate not being able to shift all the way through my cassette range.

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