SRAM’s flagship Red eTap AXS road groupset was originally launched with the same one-piece forged aluminum hydraulic disc-brake calipers used on the previous-generation Red eTap, but those have quietly been replaced with a newer two-piece unit that supposedly offers better performance and easier setup.

“SRAM made a running change to its RED eTap AXS HRD flat-mount disc brake caliper,” admitted SRAM’s senior corporate and North American road communications manager Michael Zellmann when we inquired about the brakes we spotted on team bikes at the recent Santos Tour Down Under. “This change took place on July 15, 2019. SRAM RED eTap AXS HRD post-mount brakes will remain using our one-piece, monoblock caliper. Both caliper types will come standard with Ti hardware.”

Interestingly, the updated Red design is based on the Force AXS caliper that debuted this past April, which uses two separate forged aluminum halves that are held together with separate hardware. The newer caliper design also uses bigger pads, which are now shared with SRAM’s Level mountain bike model.

According to SRAM brake product manager James Alberts, the updated caliper offers several practical enhancements, including a more consistent lever feel over the life of the pads (thanks to a new gland/seal/piston interface), and slightly better control due to increased caliper body stiffness. Pad clearance remains the same, but the more reliable seal rollback (which determines effective pad clearance) should make it easier to adjust the calipers so they don’t rub on the rotor.

Overall braking power is supposedly unchanged (despite the larger pads), although weight has likely increased by a few grams. One feature of the original caliper that some people might miss is the adjustable hose exit angle; the new caliper has a fixed-position hose that isn’t as friendly to unusual routing paths.

As this is a rolling change, end consumers are likely to see a mix of old and new product at the retail and OEM level, and there are no guarantees which version they’ll receive, especially when purchasing a new bike that was likely assembled months in advance.

“There is no trade-in policy,” said Zellmann. “However, if a rider winds up with mismatched calipers due to service, crash, or replacement, we’ll make them whole via their dealer should they want matching.”

Now, before any owners of one-piece SRAM Red calipers get all up in arms about that, keep in mind that running changes like this happen regularly throughout the industry, and they’re hardly restricted to SRAM. Shimano, for example, has rolled out a number of disc brake caliper revisions over the years, and nearly all of those changes were far less obvious than this one. Shimano has also been steadily revising its multi-piece road cassette design, which were initially prone to creaking in certain situations.

So goes the march of progress.