Technical Report XTR M9100 brakes:
: The new XTR brakes now use a four piston caliper along with a redesigned lever, a revision that's claimed to deliver more power and better modulation. I didn't have any issues with the amount of power, but the inconsistent lever feel that was present on the prior version still reared its ugly head. Even after a fresh bleed the feel at the lever was different almost every time I pulled it. Things got even worse at the end of the test period, when temperatures dropped below freezing. Mineral oil and cold temps don't go together very well, and both levers had minimal movement before they engaged. XTR drivetrain:
The XTR brakes didn't impress me, but the 12-speed drivetrain sure did. The shifter's ergonomics are excellent, with well defined ridges on each paddle for traction, and crisp, snappy shifting. It's also possible to drop down two gears with only one push of the lever, something that's not possible with SRAM's shift levers. I can't say I noticed the extra tooth on the 10-51 cassette (versus Eagle's 10-50), but every shift was incredibly smooth and precise. Maxxis Forekaster / Crossmark tires:
The tire spec on the S-120 isn't that out of line for a trail bike, but at the very least I think a Forekaster front and rear would have been a better choice. The Crossmark is a good dry conditions tire, but it can be a little, um, “interesting” when things get wet. Or just go all in and run the time-tested DHF / DHR II combo – after all, the S-120 already feels more like a trail bike than an XC whippet. Fox Stepcast 34:
The Stepcast 34 is a very impressive fork, one that's capable of handling terrain that's well outside the scope of a typical cross-country ride. However, there is one downside – the travel is limited to 120mm. That's not a big deal if you're building up an ultralight XC or marathon race machine, but the S-120 is more than that. It's the type of bike that makes you wonder how it would handle with a little more travel up front, but unfortunately the only way to find out is to install a different fork, rather than performing a simple air spring swap. The 'regular' 34 would have been the better spec choice, a few extra grams be damned.