Bikelab Inc. — Internal Tool

Dropper Post
Sizing Calculator

Enter customer inseam, crank length, and frame size to determine the correct dropper travel. Supports TurnOn, BikeYoke, and RockShox Reverb AXS in 34.9mm OD only.

⚠ 34.9 mm OD Seatposts Only — Shim Use Strictly Prohibited

The Iuhu CP and Paratu CP frames are engineered for and tested with 34.9 mm OD dropper seatposts only. Using a shim adapter (30.9 mm or 31.6 mm → 34.9 mm) is NOT permitted under any circumstances.

Without a shim the frame-to-post interface has been tested and has passed all structural tests. Shim use reduces the effective minimum insertion depth, compromises frame-to-post rigidity, and voids the frame warranty. This is a verified technical fact — not a preference.

Shim use: hard NO. No exceptions.

Customer & Bike Data
Bare feet, crotch to floor
E-bike: 155 or 160mm standard. Pedal: 155–170mm
Enter inseam to see the sizing recommendation.
Other brands not listed? This calculator supports only verified 34.9 mm OD posts from TurnOn, BikeYoke, and RockShox Reverb AXS. To request compatibility review for another brand, send the full post technical drawing (with total length, min/max insertion depths, and travel) to marvin@bikelab-inc.com. Submissions without a technical drawing will not be processed. Shim use remains prohibited regardless of brand.