Guerciotti Road Bike Size Guide: SIXTY, Veloce, Italo and Cartesio

Guerciotti sizes its road bikes by letter, XXS to XL, not by seat tube in centimetres. That makes the geometry chart the only thing worth reading, because the letter tells you almost nothing on its own. The Milanese marque is small and publishes sizing sparingly. There is no rider height table for road, and the charts sit on the product pages as drawings rather than as figures you can copy. The current range splits three ways: one race platform shared by the SIXTY, the Eclipse S and the Veloce SLR, the more accessible Veloce S and Cartesio Disc, and the endurance Italo. Browse all Guerciotti bikes at Bikeroom.

Please note. The size suggestions below are indicative and are a starting point, not a guarantee. Guerciotti publishes no rider height or inseam chart for its road bikes. Every height band here is our reading of the official stack and reach figures, not brand data. The geometry itself is Guerciotti data, taken from the size charts on guerciotti.it in September 2026. Confirm your size with a bike fit or with our team before you buy.

Quick size finder

Find your height, cross check your inside leg, then read across. The race platform, the Veloce S and the Cartesio Disc use similar bands. The Italo runs one letter smaller for the same rider, because its stack is roughly 20 to 30 mm taller at every size.

Trust the stack and reach columns in the model tables below more than these bands. They are ours, derived from geometry, because Guerciotti does not publish height ranges for road.

How to measure yourself

Height. Stand barefoot against a wall, heels together, and measure to the top of your head.

Leg length (inseam). Barefoot, feet about 15 cm apart, press a book spine up between your legs as if it were a saddle. Keep it level against the wall and measure from the floor to the top edge.

The quick formula does not apply here. The inseam multiplied by 0.66 trick only works on brands that size in centimetres. Guerciotti uses letters, so the reliable method is different: take the reach of a road bike that already fits you and match it in the tables below. Our guide on how to measure a bike frame covers how to get that number off your current bike.

SIXTY, Eclipse S and Veloce SLR (one race platform)

These are the three carbon race frames. The SIXTY is the aero flagship built for the brand's sixtieth anniversary, with Mitsubishi T65 tubing, an integrated fork with no head tube and a flattened rear triangle. The Eclipse S uses the same T65 tubing with an integrated cockpit, and the Veloce SLR steps to T45 tubing with a T47 threaded bottom bracket. Guerciotti publishes one identical sloping frame chart for all three.

Low and moderately short: a 546 mm stack at size M is racy for a 2026 frame, so riders wanting height will need spacers rather than a bigger size.

Two cautions. Guerciotti lists the SIXTY as available in XS, S, M, L and XL, while the chart it publishes for the bike still carries an XXS row. And one chart covers three different frames, so it describes the range rather than any single bike. Ask for the figures on the actual frame before committing to an integrated cockpit length.

Veloce S (carbon race, accessible build)

The Veloce S is the full carbon race frame one step below the SLR, with a press-fit bottom bracket, an alloy stem and 105 or Ultegra Di2 builds. It is offered in five sizes rather than six, and its reach curve is the least even in the range.

Watch the S to M step: reach jumps 22 mm while stack gains only 12 mm. If you sit between the two, the M will feel considerably longer, not just slightly bigger.

Italo (endurance)

The Italo is Guerciotti's endurance road bike, named after co-founder Italo Guerciotti. Guerciotti describes a slacker head angle, a shorter top tube and a taller head tube than its race frames, with clearance for 28 mm tyres. The numbers back that up: at every letter the Italo is 20 to 30 mm taller in stack than the race platform.

The S and the M share a reach of 378 mm and differ by 21 mm of stack. Between those two sizes you are choosing bar height, not length.

Cartesio Disc (entry carbon race)

The Cartesio Disc is the entry carbon road bike, with internal cable routing, a conventional 27.2 mm seatpost and 105 builds. Its stack sits close to the race platform, but it carries 5 to 9 mm more reach at the same letter.

A round seatpost and an alloy stem make this the easiest Guerciotti to adjust after purchase, which matters if your size call is borderline.

What riders say about Guerciotti sizing

Independent long term feedback on Guerciotti road bikes is thin, and we are not going to invent it. Road Bike Action and several Italian outlets have tested Guerciotti frames, but we could not reach their archives from a clean browser, so we are not quoting them. What we can state comes from the data.

• The published chart is shared. The SIXTY, the Eclipse S and the Veloce SLR carry one identical table, so choosing between them is a choice of tubing, cockpit and price, not of fit.
• Only the SIXTY lists its sizes. On the other road pages Guerciotti gives no available size list at all, only the chart.
• Guerciotti sells through dealers and offers customisation, and its gravel bikes behave the same way. Our Guerciotti gravel size guide reached the same conclusion about how little is published.

Between two sizes?

Go smaller for a sharper, lower front end and quicker handling, and larger for a longer, steadier reach on long days. A short torso with long legs points down a size; a long torso and long arms point up. Two details matter more than usual on Guerciotti. The SIXTY and the Eclipse S use an integrated bar and stem chosen at purchase, so the cockpit length is not a cheap fix later. And because the range runs low in stack, riders who want an upright position are usually better served by the Italo than by a larger race frame. Italian brands were well represented at this year's show, and our Italian Bike Festival roundup is a good place to see how the competition sizes its bikes.

Shop Guerciotti at Bikeroom

• All Guerciotti bikes for the full range, road, gravel and electric
• Road bikes to compare Guerciotti against other race and endurance frames
• Pre-owned road bikes if you want a checked frame at a lower price

Because Guerciotti gives no height chart and the race models share one table, the size call is worth a second opinion. Send us your height, inside leg and the reach of the bike you ride now, and talk to our concierge before you choose between an Italo and a race frame.

Disclaimer: the size suggestions here are indicative only and offered in good faith as general guidance. They do not guarantee a correct fit. Stack and reach are official Guerciotti figures published for the Collection 26 road range and read in September 2026, and Guerciotti can revise them between model years. Rider height and inseam bands are ours, not the brand's. Always confirm against the specific bike you are buying and, where possible, with a professional fit.

Sources: Guerciotti road range and size charts, read 24 September 2026; Guerciotti SIXTY; Guerciotti Italo; Guerciotti Cartesio Disc.