Colnago G4-X bike fit and size guide

Review the published geometry for the 2026 Colnago G4-X, compare supported sizes, and open the TrainCraft calculator with this bike preselected.

Supported sizes

450, 480, 520, 540, 570

Family

race geometry

This bike leans toward an aggressive front end, faster steering, and a more performance-oriented position.

What to compare

Stack, reach, setup

Use this guide to compare stack, reach, and gravel-specific front-end assumptions before choosing a frame size.

Open calculator with Colnago G4-X Open generic bike fit tool View original geometry source

Geometry and size breakdown

The calculator button opens the bike step with this model and size already selected. Then enter rider measurements and run the fit report.

Size	Stack	Reach	Top tube	Head tube	Stem	Crank	Fit calculator
450	535 mm	371 mm	524 mm	104 mm	90 mm	170 mm	Use in calculator
480	550 mm	380 mm	540 mm	120 mm	90 mm	170 mm	Use in calculator
520	570 mm	390 mm	560 mm	140 mm	100 mm	172.5 mm	Use in calculator
540	591 mm	400 mm	581 mm	155 mm	110 mm	172.5 mm	Use in calculator
570	600 mm	410 mm	596 mm	170 mm	110 mm	172.5 mm	Use in calculator

How to use this guide

Start with the size table to narrow the geometry range you actually want. Then open the calculator to compare that geometry against your body dimensions, flexibility, and fit priorities.

The TrainCraft bike fit tool models saddle height, cockpit reach, and bar drop using the frame geometry plus stock cockpit assumptions for the Colnago G4-X.

That is more useful than a generic height chart because two sizes can both fit your height while requiring very different stems, spacers, or saddle positions.

FAQ

What sizes are available for the Colnago G4-X?

TrainCraft currently tracks these Colnago G4-X sizes: 450, 480, 520, 540, 570. The calculator uses each size's published geometry and stock cockpit assumptions to compare fit outcomes.

Can I use the TrainCraft calculator for Colnago G4-X sizing?

Yes. Open the calculator from this page to preload the Colnago G4-X, then compare sizes against your body measurements, fit priorities, flexibility, and riding posture preferences.

What should I compare on the Colnago G4-X before picking a size?

Start with stack, reach, effective top tube, and the stock stem/crank setup. TrainCraft uses those numbers to estimate cockpit reach, bar drop, saddle position, and how much adjustment headroom each size leaves.