Zipp's components reflect the same engineering and quality you expect from their wheels. The Service Course SL Stem was developed to meet the requirements of pro cyclists, so torsional stiffness, light weight, 100% precise and effective clamping surfaces. Pro teams with Zipp sponsorship have loved the reliability, clean aesthetics, and overall performance. The Service Course SL Stem has been on winning rides at the physically demanding Paris-Roubaix, as well as the fatigue inducing Vuelta a Espana, and safely carried all team riders through the pro road and cyclocross seasons.

Crafted from 7075 aluminum, the re-designed Service Course SL Stem has a new shape that is partially oval through the body, with gentle tapers towards both clamping zones. Testing has indicated that the stem is 1.85 grams per Nm stiffer than direct competition, which any cyclist will tell you, contributes greatly to rider confidence, power transmission and handling control. The flattened surfaces of the handlebar interface and the ribbed arches of the face plate precisely and firmly clamp across 47mm. At the steerer clamp the body swells, then is sculpted towards the clamping zone. At 41mm tall, the stack height allows for low profile cockpit set-ups.

Zipp chose to use titanium Torx bolts for all six required. The T25 size is now common on many bike parts, but just in case, Zipp does provide a compatible wrench. The star shaped interface has a tighter point of contact, over more surface area, making it virtually impossible to strip the bolts as you torque to 5Nm. Again, this selection reflects the pro cycling requirements, where riders want lightweight reliability, and mechanics demand durability and ease of use to ensure rider safety.

If you want a high quality, light, stiff stem that can handle every discipline, the Service Course SL is an excellent option. You can spend twice as much on a carbon stem, but do the benefits justify the cost? In this case, likely not. In a component field with many great options, this stem stands out.