Groupsets

Shimano XTR M9100 $500 (cassette), $340 (rear derailleur), $546 (1-by crank)

In May 2018, Shimano announced its top-end mountain bike group, the xtr M9100, which included a 12-speed cassette. In fact, there are two cassettes: one that ranges from 10- to 45-tooth and another that goes from 10 to a whopping 51. The new rear derailleur shifts precisely, even under load. You can match each cassette with a 1-by crank or a traditional 2-by. There’s one set of xtr brakes for cross country riders with calipers that have two pistons each. The calipers for enduro riders have four pistons for even more stopping power. They all offer better braking modulation than the previous version of xtr, allowing you to keep things smooth on the trails. ( bike.shimano.com)

Campagnolo Record Disc Brake $3,480 (complete set)

Campagnolo was the first major component maker to introduce a 12-cog cassette to a road groupset roughly one year ago. (sram joined the 12-cogs-on-the-road club, officially, just a few months ago.) Campy slimmed down each sprocket and the chain, but ensured that everything remained durable. From the smallest cog, the 11-tooth, to the sixth largest, you get increases of only one tooth. Such a progression makes for smooth shifting and smooth pedalling. The groupset also features many other refinements. The new rear derailleur can handle both the 11–29 and 11–32 versions of the Record cassette. The front derailleur gives you two options for affixing its shifting cable, so you can find clearance for tires as wide as 32c. ( campagnolo.com)—matthewpioro