Before fully internal routing became standard, Cervelo's R3 ran shift cables along the outside of the downtube with housing stops riveted directly to the frame. The Downtube Cable Stops provide those anchor points where housing terminates and bare cable continues through a short exposed section before entering the frame near the bottom bracket. This external-to-internal transition was the standard approach on high-end carbon frames from that era before manufacturers figured out clean fully-internal solutions, and the stops take constant tension load every time you shift gears.

These stops are machined from 6000 series aluminum with a black anodized finish that matches the original factory hardware. The alloy construction handles cable tension and vibration without deforming, and the anodizing resists corrosion from road spray and sweat that accumulates on the downtube during wet rides. Unlike clip-in stops on newer frames, these mount permanently with rivets, which means replacement requires drilling out the old hardware and setting fresh rivets to secure the new stops. It's not a complicated job, but you'll need access to a rivet gun and some comfort working around carbon.

Damaged stops usually show up as cracked bodies, bent cable guide slots, or rivets that have pulled through from crash impact or years of accumulated stress. If your shifting has developed slop that limit screw adjustments can't fix, inspect the stops for visible damage or looseness at the rivet points. A stop that moves under cable load throws off the cable tension curve and makes precise shifting impossible since the system can't maintain consistent pull throughout the lever stroke. This OEM replacement restores the original cable geometry with parts that match Cervelo's specifications for the R3. Rivets are sold separately, so order those as well if your originals need replacement along with the stops themselves.