Takelast week
Shimano's 13th cog isn't a specs flex — it's a fix for a problem teams were already solving with other brands' parts. Alpecin-Premier Tech has had to bolt on non-Shimano hardware just to run a single chainring, because a 12-speed cassette leaves cadence-killing gaps once you drop the second ring.
The extra cog lets Shimano slot in a strategic 16 or 18-tooth sprocket, closing the rhythm gaps that make 1x setups punishing on rolling terrain. Tellingly, the fully wireless version of this shows up first on GRX Di2 13-speed, not Shimano Dura-Ace R9300 — the Vuelta a España test mule still looked semi-wireless. Gravel got the wireless jump first because gravel bikes take more abuse, a harsher proving ground before the tech reaches the road peloton.
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