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New SRAM Transmission Gravel Group Spotted at Unbound: 13 Speed AXS XPLR?

Keegan Swenson Unbound Bike SRAM AXS XPLR 13 speed spy shot
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Unbound Gravel is just wrapping up with another round of spirited racing right to the line. The event has also acted again as a launchpad for a new gravel drivetrain seemingly in development. This year, it seems that a new SRAM group has broken cover after being spotted on multiple bikes.

Despite SRAM remaining coy on the new components, it seems that by the time the race rolled around, none of the riders were really trying to hide anything. In the case above, Keegen Senson posted photos of his Santa Cruz Stigmata on social media, with the new rear derailleur on full display.

The key takeaway here is that the derailleur is visually different than any of the current MTB-focused SRAM Transmission options, and it appears to have a battery mounted to the top of the body like the current (and most recent) GX Eagle Transmission. Word on the street is that this derailleur is paired to a 13-speed cassette, which gives it one more than the recently updated SRAM RED road group.

Judging by the graphics on the shifters, it seems that the group still runs the newest SRAM RED shifters with updated ergonomics. Since electronic AXS shifters are just buttons essentially, it should be no problem to change the shifter to a 13-speed with a firmware update.

Keegan opted for a rigid post for the race, but the lack of a front derailleur means that the now-unused double shift function could be used to activate a RockShox Reverb AXS dropper post like existing XPLR 1x groups.

For Keegan, he wasn’t able to repeat his 2023 Unbound win, finishing with a respectable 14th for the 200-mile Elite race after Lachlan Morton blazed to the finish with a time of 9:11:47 — the fastest time to date.

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37 Comments
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Staffan Jerkeman
Staffan Jerkeman
10 days ago

How do you shift up and down with only one AXS shifter?

Taylor C
Taylor C
9 days ago
Reply to  Zach Overholt

I exclusively use the sequential shifting mode meaning I don’t actually use the “double press” to shift my chainring. I’ve always wondered if I would be allowed to remap the double press to an AXS dropper. Unfortunately my gravel bike uses an aero seat post so it’s a moot point, but I’ve always been curious.

Ashton B
Ashton B
8 days ago
Reply to  Taylor C

Yes, the “double press” function has always been able to be assigned to a Reverb AXS post (XPLR or otherwise).

Seán O’B
Seán O’B
9 days ago

The shifters are just switches, as you say, so they don’t know or care how many sprockets are out back. Ergo (sorry), they don’t need a firmware update to work with a 13-speed rear mech.

Veganpotter
Veganpotter
7 days ago
Reply to  Seán O’B

Sure? I’d love 13sp for my TT bike. But the firmware can limit a shifter which is why AXS can’t be used on a 10sp cassette…or a 13sp Ekar cassette. Obviously, SRAM can allow that whenever they’d want though

Seán O'B
Seán O'B
7 days ago
Reply to  Veganpotter

You’re conflating different aspects of wireless shifting. SRAM changed the shifter-derailleur wireless communication protocol when they went from first generation eTap (11x) to second generation [eTap] AXS (12x and now 13x), so 1st gen. shifters couldn’t talk to 2nd gen. derailleurs.

Shifter firmware has nothing to do with AXS not working on a 10x or 13x Ekar cassette, though. That is restricted by derailleur geometry and (derailleur) firmware (e.g. the lateral distance the derailleur moves when told to do so by the shifter). But yes, that is controlled by SRAM.

Jason DW
Jason DW
9 days ago

Are 13 speeds really needed?

carbonfodder
carbonfodder
9 days ago
Reply to  Jason DW

I only have two speeds: slow and stopped. An increase to 13 might pop my tiny mind cavern.
More in line with your point though, I am still firmly stuck in the 10 is enough camp and am honestly starting to get a bit worried about my ability to find NOS 10 speed bits going forward.

NotMeAtAll
NotMeAtAll
9 days ago
Reply to  carbonfodder

new from china might start to make sense. I’m using 1×9 with an 11s shimano rd, sram 9s shifter, 10s chain and 9s ztto cassete. I can now use the 9s Suntour cassete. Oh, 11/50 range.

Veganpotter
Veganpotter
7 days ago
Reply to  carbonfodder

10sp Tiagra and 105 bits will be around for a while. In 10yrs, you’ll be able to buy complete bikes with it for $150

Conal
Conal
9 days ago
Reply to  Jason DW

At some stage in the future…. “Are 14 speeds really needed?”

tom
tom
7 days ago
Reply to  Conal

The future is infini speed!

Tom H
Tom H
9 days ago
Reply to  Jason DW

Yes, to close up the annoying gear jumps from say the 13-11

Astro_Kraken
Astro_Kraken
9 days ago
Reply to  Jason DW

Depends on where you ride. I used Ekar for a few years and found I only used about the middle 8 gears. There’s too big of a concern about having a massive ratio to beat the competition’s massive ratio than maintaining a proper cadence.

Taylor C
Taylor C
8 days ago
Reply to  Astro_Kraken

Keyword is “about”. Most people only uses a few gears most of the time. The other gears are to cover you in the extremes.

Gary P
Gary P
8 days ago
Reply to  Astro_Kraken

I use all the gears on my Ekar equipped All-Road bike. And if it had a 14th cog, I’d probably use that as well. In fact, if it were a 16T cog between the 15T and 17T on my 10-44 cassette, I’d use that cog a LOT.

Not gonna lie, it’s a

Gary P
Gary P
8 days ago
Reply to  Gary P

Not gonna lie, Ekar is a bit of bear to keep well tuned with it’s tight gaps between cogs. An electronic 13 speed groupset that bypasses the traditional derailleur hanger would presumably alleviate this issue.

Veganpotter
Veganpotter
7 days ago
Reply to  Astro_Kraken

I use my full cassette 2-3 days a week…aka, every time I go into the mountains. I used my full cassette before moving to the Rockies but it was a much smaller cassette. I’d gladly have tighter gear ratios with a wide range 15sp if someone made it.

Veganpotter
Veganpotter
7 days ago
Reply to  Jason DW

No, but 10sp wasn’t “needed” either. That doesn’t mean 13sp isn’t better. I throw on a 10-36 when I know I’m doing a very long climbing day where I’d be below 60rpm with my 10-33. I don’t like the gear gaps with the 10-36 when I’m getting to the base of those climbs. With a 13sp 10-36, I’d never change my cassette. Of course, this is for 1x at the moment but 2×13 is right around the corner. And I know I appreciated the gear gap chages going from 1×11 to 1×12. With 1×13, I’d be quite happy having a slightly wider range with slightly better gear gaps.

MongoDan
9 days ago

In AXS the shifters are pretty “dumb” in the fact they are just telling the der that my button has been pressed. All the logic is in the der so there should even be a need to update the shifters and any of the current AXS shifters should be compatible as well.

For 13 speed I think it is the right more. Apparently the cassette is going to be a 10-46 which is 2 teeth bigger than the current xplr cassettes and having that one more gear should prove useful in smoothing out the gear jumps.

Veganpotter
Veganpotter
7 days ago
Reply to  MongoDan

They’ll have plenty of cassettes to pick from in 6 months. I’m sure Rival and Force will be 13sp soon enough too.

packfill
packfill
9 days ago

Just like that, Shimano is back to being irrelevant.

MisterMo
MisterMo
8 days ago
Reply to  packfill

Why is that? Shimano is just now dipping their toe into 12s gravel, albeit 2x

Tom Wenzel
8 days ago
Reply to  MisterMo

XTR M9100 released in 2018. It has received zero updates since then. Not even a gold- or copper-colored chain to stay fresh and relevant.

That is all.

SteveT
SteveT
8 days ago
Reply to  Tom Wenzel

no updates needed except for the perpetual shopper types LOL

jonathan
jonathan
6 days ago
Reply to  Tom Wenzel

it was perfect then and it still is. *fast* shifting under load.

nooner
nooner
8 days ago

Nice spy shots, did you pin on a number plate there Zach? Ben Delaney has some awesome content from Unbound for all you fellow gravel junkies: https://www.youtube.com/watch?v=-Bbur8_UcIQ Cheers!

SteveT
SteveT
8 days ago

Pretty soon the 1X cassettes will be nearly as big as the wheel circumference. LOL

mud
mud
8 days ago

This makes me wonder why the Classified hub hasn’t taken off. Weight? Cost? the proprietary cassette?

Veganpotter
Veganpotter
7 days ago
Reply to  mud

It’s hard to rationalize paying a premium for more weight and few cassette options. If it cost $1000 more but were 10g lighter than a typical setup, they’d be more popular since so many cyclists don’t really care about the price.

Evan
Evan
4 days ago
Reply to  mud

makes your second wheelset prohibitively expensive

Ryan
Ryan
8 days ago

Not one vs the other. Just more options. Pick based on your terrain and riding style. I moved back to a 2X from 1X on my new gravel bike. I ended up using it from my front door more than I had expected. Ride mixed road to the mountains and singletrack once there. I found 2X much better as I am a very strong rider and appreciate the small steps as much as the range. 1X always had me ghost shifting between 2 gears when logging distance. Once on singletrack a 1X works just fine.

mud
mud
7 days ago

Aggressive move by Sram to claim top dog status in the gravel market. Shimano’s hidebound decision makers still dissing gravel 1x.

Veganpotter
Veganpotter
7 days ago
Reply to  mud

Wait until Shimano’s replacement cranks start delaminating It’s definitely coming

Veganpotter
Veganpotter
7 days ago

Looking forward to Ratio Technology to make a new racket for 13sp. Along with potentially different cassette options from others

bikesunnybike
bikesunnybike
5 days ago

What size is that frame? Looks surprisingly small.. interested in know more about his fit and logic behind the position. While most gravel positions are inching forward, saddles slammed to the nose, negative stems, etc.

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