How to Convert Your Cervélo to a Fully Integrated One-Piece Cockpit (HB-18 Guide)
Upgrade your Cervélo bike with a fully integrated HB-18 Carbon cockpit for a clean, professional finish. This step-by-step guide shows you how to remove the old handlebar and stem setup on Cervélo frames with internal cable routing (for example, Aspero-5, Caledonia-5, Aspero from 2024, Soloist, R5, and similar models) and install the one-piece HB-18 cockpit for perfect cable integration and optimal cockpit alignment.
Full parts list:
Cervélo Split Ring
– Split Ring 312
– In the Soloist example: SR-STA also worked
Cervélo Bearing Top Cap
– BC-506 (22 mm)
– BC-413 (7 mm)
One of these is required, depending on the desired look and the transition between frame and cockpit.
Cervélo Spacer Kit
– ST31/32 Spacer Kit (5 mm and 2.5 mm pieces)
Used to adjust the cockpit height.
Cervélo One-Piece Cockpit
– HB-18 Carbon One-Piece Handlebar
Please check the manual for the maximum allowed spacer height and the torque (Nm) values to use.
Also useful
– New bar tape (optional)
– Carbon assembly paste
– Torque wrench
– Marking tape or small sticker to identify the cables
Step-by-step instruction
Preparation
Clamp the bike into a stable workstand. Keep your work area tidy and have tools ready. Prepare everything so no cables are under tension and the lines sit loose. Before disassembly, take a moment to note how the original routing runs so you have a reference later.
Remove the old handlebar and stem
First remove the bar tape, then expose the brake and shift lines. Next loosen the stem bolts and remove the handlebar assembly. Remove the old spacers, the top cap and all parts of the previous cockpit. Then clear the head tube and quickly check the bearings to make sure they are clean and rotate smoothly.
Install the split ring
Now fit the original Cervélo split ring. On the Soloist the SR-STA fit, otherwise use the Split Ring 312 to be safe. It is inserted at the top of the head tube and ensures the internal routing lines up correctly with the new cockpit. The ring must sit flush and even. (It only fits one way anyway, since it is tapered.)
Install the bearing top cap
Choose the correct bearing top cap. The BC-506 (22 mm) gives a higher, fully integrated transition; the BC-413 (7 mm) gives a flatter, more minimal line. The top cap sits directly on the frame and forms the upper finish over the split ring. It affects the final look and how the cables run beneath the cockpit.
Set spacer height
Now set the final cockpit height using only the Cervélo ST31/32 spacer kit. The spacers combine in 5 mm and 2.5 mm steps. Stack them provisionally to get a feel for how high the cockpit will sit.
Mark and prepare the cables
Before pulling or rerouting any cables or hoses, mark them clearly. Mark the left side with a white marker so you know later which cable belongs where. Prepare the housings/cables so they can be fed through the new unit without trouble.
Feed the HB-18 cockpit
Lay out the new HB-18 Carbon One-Piece cockpit. Feed the marked cables one by one through the frame, through the bearing top cap, through the spacers and finally through the channels in the cockpit. Take your time and make sure the lines do not twist and can move freely. When everything is through, carefully set the cockpit onto the head tube.
Align and tighten
Align the cockpit so it is straight and choose the final spacer stack. Lightly preload the top cap to set the headset without play. Then tighten the cockpit clamps and fasteners to the correct torque. Always follow Cervélo torque specifications.
Connect cables and finish up
Check brake line lengths and cable tensions. If hydraulic brakes were opened, bleed them as required. Check the steering range to ensure no cable is under tension or rubbing on the frame. Do a short test ride and then recheck all fasteners.
Done
The Cervélo is now converted from a classic handlebar-stem setup to a fully integrated one-piece cockpit. The bike looks much cleaner, cables are fully hidden in the system and the bike gets the modern Cervélo appearance found on the newer models.
If you don’t want to do the conversion yourself or if you have questions about specific models or model years, get in touch anytime. We’re happy to help or guide you step-by-step for a specific model.
