Triathlon and Time-Trial Bikes
Used time trial and triathlon bikes from private sellers across the UK, designed around one thing: aerodynamic efficiency. Cervélo P-series, Canyon Speedmax, Trek Speed Concept, Specialized Shiv and Giant Trinity dominate the market, and many come to the used market with very low mileage.
What makes a TT bike different?
Steep seat tube angles of 76–80° push the rider forward over the pedals, while clip-on aero bars and integrated frame shapes minimise frontal area. These bikes are compromised in every way except going fast in a straight line — they climb poorly, handle nervously, and can't be used in bunch races. For those, look at the road bikes listings instead. But for TTs and triathlon bike legs, nothing else comes close.
TT bike or triathlon bike?
There are subtle differences. Pure TT bikes used in time trials must comply with UCI regulations on frame shape and dimensions. Triathlon bikes don't follow UCI rules and can be more radical in design — deeper tube sections, integrated storage, and a wider saddle-to-bar position for running afterwards. Most TT bikes work for triathlon, but some tri-specific bikes (Cervélo P5, Canyon Speedmax CFR) aren't UCI legal, so check compliance before buying if you race both disciplines.
How important is fit?
Position is everything. The aggressive aero position — flat back, narrow arms on aero bars, forward saddle position — needs a professional bike fit, because an uncomfortable TT position costs more time through fatigue than it saves in aerodynamics. Aero bar width, pad height, extension length and armrest angle all need dialling in. Stack and reach can be adjusted with spacers and stem length, but the frame needs to be in the right ballpark; a frame that doesn't fit can't be made to fit with adjustments alone, which makes used TT bikes risky without test-riding. If the fit numbers push you towards a more relaxed position, an endurance bike may serve you better.
Which aero features matter?
Modern TT bikes integrate everything for clean airflow: internal cable routing, hidden brakes (or flat-mount discs), integrated bottle storage behind the stem or between the arms, and deep-section aero seatposts. Disc rear wheels and deep-section front wheels of 60–80mm are standard race setups, though full disc covers aren't legal in all events — check the rules. Frame storage for nutrition is critical in triathlon, and some bikes include bento boxes and between-arm bottle mounts as standard.
What gearing and groupset should I look for?
TT gearing is typically big — 54/42 or 55/42 chainsets with 11-25 or 11-28 cassettes, since courses are usually flat or rolling and low gears aren't needed. Electronic shifting (Shimano Di2, SRAM AXS) is almost essential, as shifting from aero bars with mechanical systems is clunky; Shimano Ultegra Di2 is the value choice, and some riders use bar-end shifters with mechanical groupsets as a budget alternative. TT-specific brake levers mount on the aero bar extensions so you can brake without leaving the aero position.
What should I check buying used?
TT bikes are often lightly used — many triathletes ride them only on race day and a few training sessions — so low mileage is common and the value is excellent. Proprietary parts are the main concern: integrated seatposts, specific aero bars and non-standard components can be expensive or impossible to replace, so check parts availability on older models. Verify the frame hasn't been crashed, which is common in group triathlon starts, and test electronic shifting fully, since batteries and junction boxes on aero bars are exposed to weather. Sizing is critical — a used TT bike that doesn't fit is essentially worthless to you.