The Race Face Aeffect R Stem, configured with a 35 mm handlebar clamp, a 40 mm length, and a black finish, is a rugged, zero-rise cockpit option engineered for aggressive Trail, All-Mountain (AM), and Enduro mountain biking.
While the ultra-stubby 32 mm variant focuses strictly on hyper-responsive steering, this 40 mm extension strikes a perfect middle ground for modern mountain bike geometry. It lengthens the cockpit just enough to prevent the frontend from wandering on steep technical climbs, while still offering the sharp, lightning-fast downhill handling demanded by trail riders.
Component Specifications
Length: 40 mm (a highly popular mid-length for modern long-frame geometry).
Handlebar Clamp Diameter: 35 mm (exclusively fits oversized 35 mm bars).
Material Architecture: 3D forged from high-strength 6061 aluminum alloy, then CNC-machined in high-stress zones.
Weight Profile: Approximately 140 to 145 grams (scales slightly above the 131g reference weight of the 32 mm sibling).
Application Rating: Down-Country, Trail, All-Mountain, Enduro, and e-MTB.
Core Mechanism & Design Features
Top-Lock Zero-Gap Interface: This mechanism simplifies handlebar installation by eliminating uneven bolt loading. The rider tightens the upper two faceplate bolts completely flush against the stem body first, removing the top gap. Once closed, the lower two bolts are torqued down to specification, distributing pressure evenly to safely clamp alloy or carbon bars without crushing them.
Continuous Spine Aesthetic: The industrial CNC forging creates a solid metal spine that flows into the faceplate seamlessly, optimizing torsional stiffness while giving the cockpit a clean, sweeping look.
Built-In Trail Protection: Backed by the robust Race Face Lifetime Warranty, meaning your component is fully covered even if it takes a direct impact during a crash on the trails.
