Bianchi Time Trial Size Guide: Aquila RC and Aquila CV

Bianchi sizes its time trial frames in letters rather than centimetres, and that is where the confusion starts. The current Aquila RC comes in three sizes, S, M and L. The Aquila CV that preceded it came in four, XS, S, M and L, and the letters do not describe the same bike. Browse the Aquila collection or the full Bianchi range at Bikeroom.

Please note. The size suggestions below are indicative. They are a starting point built on official geometry and average body proportions, not a guarantee of fit. On a time trial bike the arm pads decide the position, and pad height and pad reach can be adjusted well beyond what the frame label suggests. Confirm your size with a professional bike fit, or with our team, before you buy.

Why a time trial size is not your road size

On a road frame, stack and reach tell you roughly where your hands will sit. On a time trial frame they do not. Your upper body rests on the arm pads, so pad stack and pad reach, both measured from the bottom bracket, are the numbers that set the position. Frame stack and reach only define the starting point for the cockpit.

Seat tube angle is the second difference. A Bianchi road race frame sits near 73 degrees. Time trial and triathlon frames run from about 76 to 80 degrees, rotating the pelvis forward so the hip angle stays open when the torso drops. Bianchi quotes 76.5 degrees on the Aquila CV and 77.5 degrees on the Aquila RC, and says the steeper number reflects what its WorldTour time triallists asked for.

The third is that many riders end up a size below their road size, because the front end needs to come down and the pads sit ahead of the head tube. Our Bianchi road bike size guide is the right reference for the road half of that comparison.

The fourth is the rulebook. UCI article 1.3.013 puts the tip of the saddle at least 5 cm behind a vertical plane through the bottom bracket. A morphological exemption is available on request. The rules also limit how far the extensions may reach forward. Non-drafting triathlon has no such limit. The Aquila is built for the UCI side of that line, a point we cover in our guide to time trial bikes versus triathlon bikes.

One limit to flag. Bianchi does not publish a pad stack and pad reach table for either Aquila. What it does publish is the spacer kit: BikeRadar reported at the RC launch that the extensions come with 5, 10 and 20 mm spacers for a maximum pad rise of 75 mm.

Quick size finder

Find your height, cross check your inseam, then read across. The two generations are shown separately because their size letters do not match.

The Aquila RC range stops at S, so riders under roughly 170 cm are better served by the CV in XS. Inseam is a better guide than height, and your current pad stack and pad reach are better than either.

How to measure yourself

Height. Stand barefoot against a wall, heels together, looking straight ahead. Rest something flat on your head, level against the wall, mark the point and measure from the floor.

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

Bianchi does not publish a centimetre size for the Aquila, so the road shortcut of multiplying inseam by 0.66 does not translate here. Use the stack and reach tables instead.

Aquila RC (current time trial flagship)

Bianchi says the Aquila RC took 20 months to develop with its WorldTour riders, including Tour de France stage winner Kévin Vauquelin. It claims a 1.3 kg frame and a 400 g fork, clearance for 28 mm tyres, and a saving of 16.1 watts at 50 kilometres per hour against the previous generation. Those are manufacturer claims, not independent test results. Three sizes, a 77.5 degree seat tube angle throughout and 410 mm chainstays.

Official Bianchi geometry for the Aquila RC, read on bianchi.com in September 2026. Seat tube angle 77.5 degrees, head tube angle 72 degrees in all three sizes. Bianchi does not publish a rider height range per size.

The jumps here are unusually even: 14 mm and 24 mm of stack, 18 mm and 20 mm of reach. That makes the RC easier to size than most time trial frames, provided you fall inside the range at all.

Aquila CV (previous generation)

The CV was the last rim brake bike racing in the WorldTour, as BikeRadar noted when the RC replaced it. It is the version most likely to turn up pre-owned, and it is the one that covers smaller riders. Four sizes, a 76.5 degree seat tube angle, 398 mm chainstays and an aero seatpost with a reversible head giving plus or minus 18 mm of saddle setback. Bianchi lists a 300 mm post for XS and S, and a 350 mm post for M and L.

Official Bianchi geometry for the Aquila CV, from the archived Bianchi USA frame kit page. Seat tube angle 76.5 degrees, head tube angle 72 degrees in all four sizes.

Read the two tables together and the picture is clear. The CV L is 26 mm taller than the RC L at the same reach, and the CV XS has no equivalent in the current range. Bianchi's site now lists only the Aquila RC under time trial and triathlon, so the chart above is the last geometry it published for the older frame.

What riders say about Aquila sizing

The pattern in the press coverage is consistent, and it is about position rather than frame size. BikeRadar's Warren Rossiter described the RC as the bike that finally moved Bianchi's time trial platform to disc brakes, with a wider fork crown and a cleaner head tube junction. The fit story that comes with it is a lower, longer front end than the CV offered.

Bianchi itself is unusually direct about the intent. Its own copy says the more upright 77.5 degree seat tube angle reflects the preferences of elite time triallists, and that reach was increased while top tube length stayed the same. Read that as a warning: the RC is a professional fit first, and riders moving across from a CV should expect to lose stack and gain reach at the same letter.

The third pattern is the cockpit. The RC ships with a Vision FSA front end and a fixed set of spacers, so the pad height range is finite. If you already run a large spacer stack on your current bike, check the numbers before you choose a size, not after.

Between two sizes?

Go smaller for a lower, shorter, sharper position, and if you race short time trials where the position is held for under an hour. Go larger for stability and for long distance, and if your pads currently sit near the top of their range. A long torso and long arms point up a size, long legs and a short torso point down one.

On the Aquila the frame is only part of the answer, because the seatpost head is reversible on the CV and the spacer stack is limited on the RC. If you are shopping pre-owned, our practical guide to buying a used triathlon bike covers what else to check, and our Bianchi at the Vuelta piece covers how the range is raced.

Shop Bianchi time trial bikes at Bikeroom

• Bianchi Aquila for the RC and CV frames and complete bikes in stock
• Time trial and triathlon bikes for the whole category across brands
• Pre-owned triathlon bikes if you would rather buy used
• All Bianchi for the road, gravel and mountain range

If you are moving from a CV to an RC, the question is whether your current position still fits. Send us your pad stack and pad reach, or talk to our concierge before you choose a letter.

Disclaimer: the size suggestions in this guide are indicative only and given in good faith as general guidance. Stack, reach, head tube and wheelbase figures are official Bianchi data for the model generations named, read in September 2026, and can change between model years. The rider height and inseam bands are Bikeroom's own reading of that geometry, not manufacturer data. Always confirm against the specific bike you are buying and, where possible, with a professional fit.

Sources: bianchi.com Aquila RC geometry; Bianchi USA archived Aquila CV frame kit geometry; BikeRadar, Warren Rossiter, 6 February 2025.