Light and stiff got married
Zipp doesn't hesitate to extend its craftiness beyond its signature aerodynamic wheels. This SL Speed Carbon Stem is a prime example of Zipp's quest to reshape bike componentry from bottom to top. The most notable aspect of this stem is its ethereal lightness (a mere 102 grams in 100mm length). Being this light, Zipp uses exacting construction standards and some forward thinking to maintain the same top-notch level of performance and durability you'd find on Zipp's other race-day products.
The SL Speed Carbon stem has rearward facing stem bolts, similar to what we've seen on Oval stems in the past. On Zipp's design, the bolts thread directly into a two-piece carbon/titanium faceplate. On the backside, the single-bolt steerer clamp appears standard in every way, but Zipp found, through product testing, that normal fasteners don't always seat properly in their bores when the clamp is torqued to spec onto the fork steerer tube. To alleviate this, Zipp added self-aligning washers to ensure positive contact between the stem and the shoulders of the fasteners. This minute detail is one that allowed Zipp to create the main structure of the SL Speed Stem from 100% carbon fiber, without any co-molded alloy parts.
The Zipp SL Speed Carbon Stem uses uni-directional carbon fiber, laminated in such a way as to have incredible torsional stiffness to resist twisting when you're really cranking on the bars in a sprint or uphill. It has a 31.8mm clamp diameter and is available in six lengths from 80 to 130mm in 10mm increments. The stack height at the steerer clamp is 40mm and the stem is angled at +/- 6 degrees. Please note that this stem does not include a top cap.