Colnago gravel sizing: G4-X, G3-X and C68 Gravel
Colnago builds gravel around two characters. The G4-X is the current race model, and the outgoing G3-X shares its exact fit, so the two size identically. The handmade C68 Gravel sits a little taller and more relaxed for endurance riding. The most useful thing to know is that Colnago labels its gravel frames by a numeric size rather than S, M or L, and the position differs between the race G series and the endurance C68, so pick the model for the ride you want first, then size by height and reach. Explore what is available on our Colnago collection.
Please note. The recommendations below are indicative and a starting point, not a guarantee of fit. Riders of the same height vary in torso and leg proportion, flexibility and style, so treat the height and inseam bands as a guide and confirm against the exact bike before you buy.
Quick size finder
| Rider height | Leg length (inseam) | G4-X / G3-X | C68 Gravel |
|---|---|---|---|
| 155 to 168 cm | 70 to 76 cm | 450 | 450 |
| 168 to 176 cm | 76 to 80 cm | 480 | 480 |
| 176 to 184 cm | 80 to 85 cm | 520 | 520 |
| 184 to 191 cm | 85 to 89 cm | 540 | 540 |
| 191 to 197 cm | 89 to 93 cm | 570 | 570 |
How to measure yourself
Height. Stand barefoot with your back to a wall, heels together, and mark the top of your head. Measure straight down to the floor.
Leg length (inseam). Barefoot, feet about 15 cm apart, raise a hardback book spine up firmly against your sit bones as a saddle would sit. Measure from the top of the book to the floor. Your inseam matters more than height for standover clearance and saddle height.
Colnago G4-X
The G4-X is the current gravel race bike, with an aggressive position that pitches you forward and high for pace on fast, flowing gravel, plus clearance for tyres up to 45 mm.
| Size | Reach (mm) | Stack (mm) | Rider height |
|---|---|---|---|
| 450 | 371 | 535 | 155 to 168 cm |
| 480 | 380 | 554 | 168 to 176 cm |
| 520 | 390 | 573 | 176 to 184 cm |
| 540 | 400 | 591 | 184 to 191 cm |
| 570 | 410 | 600 | 191 to 197 cm |
Fit character: forward and racy, built for gravel pace.
Colnago G3-X
The G3-X is the outgoing race model and shares the G4-X geometry exactly, so if a G3-X is the bike in front of you the fit and sizing match the table above. It uses Colnago's s size labels, from 46s to 58s.
| Size | Reach (mm) | Stack (mm) | Rider height |
|---|---|---|---|
| 46s | 371 | 535 | 155 to 168 cm |
| 49s | 380 | 554 | 168 to 176 cm |
| 52s | 390 | 573 | 176 to 184 cm |
| 55s | 400 | 591 | 184 to 191 cm |
| 58s | 410 | 600 | 191 to 197 cm |
Fit character: identical to the G4-X, a road inspired all rounder.
Colnago C68 Gravel
The handmade C68 Gravel is the endurance option, more upright and stable with a taller stack, shorter reach and a longer wheelbase for calm handling over distance.
| Size | Reach (mm) | Stack (mm) | Rider height |
|---|---|---|---|
| 450 | 375 | 541 | 155 to 168 cm |
| 480 | 386 | 555 | 168 to 176 cm |
| 520 | 397 | 580 | 176 to 184 cm |
| 540 | 408 | 605 | 184 to 191 cm |
| 570 | 419 | 630 | 191 to 197 cm |
Fit character: taller and more relaxed, a stable endurance gravel racer.
What Colnago riders find
Reviewers describe the G series as road like in precision and power transfer, so direct that Colnago itself suggests a slightly shorter stem to liven up the steering, and they note the G4-X pitches you forward and high for a committed race position. The C68 Gravel draws praise for its handmade frame and comfortable, planted feel, though testers point out its integrated cockpit comes in a single width, so it suits riders whose bar preference matches. Across the range the main gripe is the premium price rather than the fit.
Between two sizes?
If your height and inseam fall on a boundary, think about position. Choose the smaller size for a racier, lower front end and quicker handling, and pair it with a slightly longer stem if you want more reach. Choose the larger size for a taller, more relaxed front end that suits long days. Comparing the stack and reach of a bike you already ride is the most reliable way to decide, and remember the G4-X and G3-X share one fit while the C68 Gravel sits taller.
Shop Colnago gravel bikes
See current availability and specs on our Colnago collection.
Choosing between the race G series and the endurance C68 Gravel, or unsure on size? We are glad to help. Talk to our concierge.
Stack and reach figures are drawn from official Colnago data where possible. Rider height and inseam bands are indicative estimates based on Colnago's own guidance and should be treated as a starting point. The G3-X is an outgoing model that shares the G4-X fit; confirm current availability. Always confirm geometry against the exact bike and model year before buying.
