Colnago G4-X Review: A Gravel Race Bike With Road Bike DNA

Introduction

The Colnago G4-X is the Italian brand’s newest gravel race bike, and it arrives with a clear brief: take what Colnago has learned on the road and translate it into a machine built for fast gravel racing. Tire clearance grows to 45 mm, the front end is completely redesigned around an integrated cockpit, and the tube profiles borrow heavily from the V4RS road race bike.

That direction shapes everything about the ride. The G4-X is quick, stiff, and road-like, which is exactly what a gravel racer wants on wide open courses. It is also a bike that asks a fair amount of the rider, and at the top of the range it asks a fair amount of your budget too.

What Is New on the Colnago G4-X

The headline change is tire clearance. The previous G3-X accepted 42 mm tires, which is workable for racing but limiting for riders who want more versatility. The G4-X moves that figure to 45 mm, and the extra room comes mainly from a redesigned chainstay. The section directly behind the bottom bracket is now taller but noticeably thinner, and the effect is most obvious on the drive side, where there is just enough space for a mechanical gear cable outer to pass through.

Up front, Colnago fits the CC.01 integrated bar that first appeared on the C68, now offered in a new wide version with 6 cm of flare at the drops. The measurement is 40 cm at the hoods and 46 cm at the drops. The frame also carries a number of tube shapes and lessons from the V4RS road race bike, and Colnago says feedback from riders at the top of the sport has pushed its range toward stiffer, lighter frames.

Finishing touches are aesthetic as much as functional. Three gravel-inspired colors join the range, including the sandy yellow shown here, along with a split logo that puts half the graphic on each side of the frame.

Who the Colnago G4-X Is For

This is a race bike first. Riders who chase results on fast, wide gravel courses, or who mix long road stretches into gravel routes, will find the position and the response familiar and welcome. Anyone coming from a road background gets a very similar fit, which makes the transition easy and keeps you efficient when a route strings together tarmac and gravel.

Riders who spend most of their time on technical descents, loose surfaces, or multi-day adventures should think carefully. The G4-X is built around speed and stiffness rather than comfort and compliance, and that character is worth matching to the riding you actually do.

Main Strengths: Stiffness, Speed, and a Road-Like Position

The stiffness is the defining trait. On smooth gravel, steep climbs, and faster road sections it translates into a direct, efficient feel. Acceleration is strong, and on climbs that rise in steps the bike holds speed through the steep ramps rather than sagging. Sprinting from the drops feels quick, and the wide CC.01 bar gives plenty of leverage when you are pushing hard.

The low-slung ride position is another strength. Hunkering down for road sections feels natural, and the overall geometry reads much like a road bike, so riders making the switch do not have to relearn how the bike wants to be ridden.

Descending is where the road DNA shows most clearly. The G4-X felt composed enough on wet lanes and gravel roads to tip into corners and link a few apexes together, which is high praise for a bike carrying this much frame stiffness.

Ride Impressions on Wet Gravel and Steep Climbs

Conditions were far from ideal, with heavy rain cutting a planned 50 km route down to roughly 23 km. Even so, the route packed in climbing, flowing descents, twisty singletrack, and a stretch of road, which was enough to form a first impression.

The bike carries a little more weight than a pure climbing machine, and the weight balance felt a touch too far forward for the loosest, steepest descents. Braking performance also left room for improvement in the wet. The stiffness that makes the bike so quick on smooth surfaces becomes more noticeable on rougher descents, where you feel the frame working through the bike and into you.

Tires played a part. The Pirelli tires fitted here are dry summer rubber, and the low shoulder knobs had to work hard for traction in the wet. On smooth road and gravel the slick central tread came into its own, and the bike was very happy holding speed.

Things to Consider Before Buying

The cockpit is the most concrete limitation. The CC.01 wide bar comes in five sizes, but those are stem sizes. The bar itself is fixed at 40 cm at the hoods and 46 cm at the drops, and Colnago does not offer an alternative width. The saving grace is the 1.5 inch upper bearing, which allows a standard 1 1/8 inch steerer, so a different stem and bar combination from almost any brand will fit if the stock setup does not suit you.

Some finishing details also feel below the price point. The drive side chainstay protector felt loose, the seatpost clamp cover felt flimsy, and the top tube cover for the bar bag bolt felt plasticky and thin. Nothing rattled during the ride, but these are the parts that stand out when a bike costs this much.

Tire clearance, while improved, is not class-leading. Other gravel race bikes offer 47 mm and even 50 mm of room, and those brands use the extra clearance to soften the ride. That leads to the final point: the G4-X is deliberately stiff, and riders who are not racing at the front may find a more compliant frame serves them better over a long day.

Build Options and Buying Advice

The range opens with two Shimano GRX RX820 builds, one 1x and one 2x, both priced at £4,500 or $4,750. These are the only two builds coming to the UK, and there is no Campagnolo option anywhere in the line. At the top sits a SRAM Red AXS build with Zipp 303 S wheels and Pirelli tires at $9,750, which is steep, and notably it ships without a power meter on the chainset.

If the geometry and the race-focused ride appeal to you, the Shimano builds represent the more sensible entry point, since prices fall as you move down the SRAM groupsets. Colnago says availability starts on 20 June, so there is time to weigh it up. Riders who want a versatile all-rounder may prefer to look at bikes with more tire clearance and a softer frame, while committed gravel racers will find the G4-X does exactly what its brief promises.

Conclusion

The Colnago G4-X is a focused gravel race bike, and Colnago has not reinvented its formula so much as sharpened it. The 45 mm clearance, the new integrated front end, and the V4RS-derived frame make it fast and rewarding on smooth gravel and road, and the road-like position will suit anyone crossing over from tarmac.

The trade-offs are honest ones. Stiffness that helps on climbs and fast courses works against you on rougher descents and long days, the cockpit offers no width choice without a swap, and some small details do not match the price. For a rider chasing speed on gravel, those are reasonable compromises. For everyone else, it is worth a test ride before committing.