The M988 brakes feature a more contoured and dimpled brake lever over the M987 Race version. The M988 are about 40 grams heavier per wheel than the M987 due to an alloy lever body and caliper in lieu of the magnesium on the M987.
Shimano XTR is synonymous with the absolute pinnacle in quality for mountain bike component. Shimano's disc brakes have always been pretty good compared to the competition but Shimano's engineers got serious with the 980 series to produce a disc brake that is noticeable better and more reliable than anything else on the market. The renowned German test institute Velotech.de confirmed the XTR brakes are heads and shoulders better than their competition in terms of reliability, braking power and fade resistance.
Shimano discovered a weak link of and hydraulic brake system is the hose. Hoses can bulge and expand under high braking force and diminish rear braking in particular. You will notice the hose included with the M988 brakes features "Shimano high power brake hose" in gold letters to emphasize the use of an ultra-premium bulge-resistant hose created with a compression resistant mesh encasing the inner hose.
The fluid is held in an integrated barrel reservoir with a hinged handle bar. The hinged clamp is I-spec B compatible, which means it will allow a 980 series I-spec B shifter to be attached to the clamp so you will only have one clamp for both brake and shifter on your handlebar. The polished silver calipers have an oversized 22mm ceramic piston. The Ceramic piston is a natural insulator. Ceramics are harder and much more uniform in shape as well as being stiffer for stronger, more even braking pressure. This unit is pre-bled, meaning, the hose is attached to both the lever and calipers and is ready for action, right out of the box.
Rotor and adapters not included - sold separately. Use with Shimano Ice Tech or Freeza rotors for maximum performance and virtually no fade.