SRAM Drops 13-speed RED XPLR AXS
The American bicycle components company SRAM launched a new groupset today, an expansion of the XPLR series. It is SRAM RED XPLR AXS and to recap RED is SRAM’s flagship, topline groupset, AXS denotes electronic and XPLR is 1x (1 chainring, no front derailleur). This groupset is 13-speed and the cassette gearing is 10-46.
This groupset continues to prosecute SRAM’s belief in 1x even as SRAM made significant improvements to its front derailleur shifting when launching its new RED 2x group in May.
This new XPLR upgrade is gravel-oriented and will appeal to serious gravel riders, both the functionality of the groupset itself and the mounting platform it uses. SRAM has its own standard for how rear derailleurs mount to frames, called UDH, which stands for Universal Derailleur Hanger though in fact direct-mount derailleurs omit the hanger from the system (which can be seen from the images herein). OPEN Cycles describes UDH as it explains why it has chosen to begin making its frames with the UDH standard.
SRAM’s 1x RED XPLR groupset shares certain components with its 2x RED road groupset: the controls (shifters), brake calipers, brake rotors, and Flat Top chain. The heart of this system is the rear derailleur and cassette and the RD is entirely new. While MTB has been using UDH for years this new RD is not the same as that on the SRAM Transmission. That MTB rear derailleur, called Eagle Transmission or just Transmission for short, also uses the UDH interface. This new XPLR groupset takes the UDH into gravel and like other UDH derailleurs it has no b-tension and no hi- or lo-limit screws. The difference between the groupsets and, specifically, the RDs is that Transmission prioritizes shifting under load whereas RED XPLR prioritizes shift speed. There is a clutch in the RED XPLR RD, but it is tuned for gravel. Like SRAM’s Eagle and Transmission RDs there is a cage lock for wheel removal.
The 10-46 cassette is just that: a single gearbox option. It fits into a standard-spaced frame and can mount on an XDR driver body because the UDH’s hangerless design allows the clearance for the 13th cog. This cassette weighs 288g and the first 3 cogs are aluminum. One other major departure from Transmission is that all SRAM’s MTB products use the Eagle chain while XPLR – this group included – use the Flat Top chain, which has previously been pretty much road-specific.
RED XPLR’s crankset has a Q factor of 150mm which is just like road, as opposed to the 170mm or 175mm Q found on MTB groupsets. Crank lengths range down to 160mm. The power meter is a threaded, spin-on, rather than the more familiar 8 bolt direct mount. This allows the chain rings to be replaced. Claimed accuracy on the PM is +/- 1.5% and of course the PM tech is driven by Quarq, long a member of the SRAM family. Chain rings range from 38t to 46t, with available aero rings from 48t to 52t.
Is this a tech for tri bikes? It could be with one exception: The minimum chain stay length is 415mm. This would work fine for a Canyon Speedmax, which has an unusually long 425mm chain stay, but a lot of tri bikes do not have chain stays as long as 415mm. (This is one reason Canyon athletes Jan Frodeno and Lionel Sanders could successfully ride 1x drive trains for years.)
Could this be a future tri bike groupset? Its 13 speeds are compelling. It would mean that tri bike makers would incorporate 2 changes in their designs: longer chain stays (which would not impede the handling of the bike and might improve on handling) and the incorporation of the UDH system, which is not a problem because the insertion of a derailleur hanger into the UDH hole converts a frame to a standard road motif.
Is this SRAM’s best gravel 1x option? Maybe. SRAM still offers the “mullet” config, which is MTB behind the crankset and road from the crankset forward. The rear of the bike would use the Transmission RD and cassette and the Eagle chain and would also mount directly to the UDH hole in the frame. The advantage to the mullet is the wider gear range (10-50 or 10-52 cassette). The advantage to RED XPLR is 13 speeds, a tighter ratio gearbox, and the features written about herein.
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