The IRONMAN bike glossary. Every cycling term you need for the bike leg, from aero to watts.
BIKE
New to the bike leg, or just want the lingo down? This glossary explains the cycling terms you will hear in training and on race day, from your aero position to drafting rules, kit, and quick fixes. Skim it, or jump to what you need.
The Tri Bike and Aero Setup
Tri bikeA time-trial or aero bike built for triathlon. Light, with bar and seat-post setups that let you ride comfortably in the aero position.
AerobarsBars that clamp to your base bars or stem and let you ride in the aero position. More comfortable and more aerodynamic for racing. They can also go on a road bike.
Base barsThe main handlebars you hold for climbing, cornering, and control, with the aerobars mounted on top.
Aero positionAlso called the time-trial position. Riding hunched over with your elbows resting on the aerobar pads. It saves your running muscles and keeps you aerodynamic, especially on flatter courses.
Aero bottleA bottle mounted on the aerobars so you can drink without leaving the aero position. It can also mean an aerodynamically shaped bottle on the down tube.
Disc wheelA solid, spokeless wheel that is very aerodynamic, often used as the rear wheel in triathlon.
Frame and Components
Down tubeThe frame tube that slopes from the front of the bike down toward the rear wheel.
Top tubeThe frame tube that runs from the front of the bike, between your legs, back toward the rear wheel.
Seat postThe tube that holds your saddle and sets your height. On some tri bikes it can be cut to fit.
SaddleThe bike seat. A good tri saddle supports you comfortably in the aero position.
Gears (cassette)The set of cogs on your rear wheel. Shifting gears changes how hard each pedal stroke feels.
DerailleurThe mechanism that moves the chain across the gears when you shift.
Clipless pedals and cleatsPedals that lock onto cleats on your shoes so your feet stay connected for a stronger, more efficient stroke. Despite the name, you clip in.
TubeThe rubber inner tube that sits inside a bicycle tire.
Tubeless tiresTires that seal to the rim and run without a separate inner tube.
Power and Pacing
CadenceYour pedaling speed, also called RPM, or revolutions per minute.
Power meterA tool on the bike that measures the power, in watts, that you are producing.
WattsThe unit of power you generate on the bike, measured by a power meter.
SpinTo ride easy with very low resistance, as in an easy spin.
HammerTo pedal very hard for an extended stretch, as in that ride was a hammer-fest.
Time trialA ride at your maximum sustainable pace, usually in the aero position. The bike leg of most triathlons is a time trial.
TrainerA stationary trainer for indoor riding and intervals, as in I did a killer trainer workout.
Racing and Group Riding
DraftingRiding close behind another rider so their wind resistance makes your pedaling easier. This is not allowed in most triathlons. Stay out of the draft zone behind the rider ahead, which is 12 meters at many IRONMAN events, and complete any pass quickly. Check the official IRONMAN Competition Rules for your race.
PelotonThe large main group on a group ride. Not allowed in IRONMAN racing.
DroppedWhen you fall too far behind a group to stay in the draft, the gap grows, pedaling gets harder, and you cannot catch back on. That is getting dropped.
BrickA workout of two disciplines back to back, most often a run straight off the bike, or a ride straight after a swim.
Kit and Comfort
JerseyA cycling top in technical fabric, usually with a front zip for airflow and rear pockets for food and tools.
BibsPadded cycling shorts attached to a bib section that goes up and over the shoulders.
KitYour full set of cycling clothing worn together, often matching: shorts, jersey, gloves, socks, vest, jacket, arm warmers, and so on.
Arm warmersSleeves worn in cooler weather to shield the arms. Easy to remove mid-ride and stash in a pocket.
Arm coolersLike arm warmers but in thinner fabric, made to shield your arms from the sun in the heat.
Chamois creamA cream applied to the crotch area to ease chafing between the saddle, shorts, and skin.
Fuel and Fixes
BonkRunning out of fuel on a long ride so your blood sugar drops, your head goes foggy, and your legs quit. The fix is to eat quickly and eat plenty. Also called hitting the wall.
Bento boxA small bag that attaches to the top tube to hold food and tools within easy reach.
CO2 cartridgeA small cartridge of compressed gas that inflates a flat tire fast, so you can get rolling again.
Frequently Asked Questions
What is the IRONMAN bike distance?
The bike leg is 112 miles (180 km) in a full IRONMAN and 56 miles (90 km) in an IRONMAN 70.3. It is the middle leg, between the swim and the run.
What is the aero position?
The aero, or time-trial, position means riding hunched forward with your elbows resting on the aerobar pads. It cuts wind resistance and saves your running muscles for the run leg.
Is drafting allowed in an IRONMAN?
No. IRONMAN is a non-drafting race. You must stay out of the draft zone behind the rider ahead, which is 12 meters at many events, and pass promptly. Always check the official IRONMAN Competition Rules for your race.
What is a brick workout?
A brick is two disciplines back to back, most often a run straight off the bike. It trains your legs for the jarring change from riding to running on race day.
What does it mean to bonk?
To bonk is to run out of fuel on the bike. Your blood sugar drops, your focus fades, and your legs stop responding. Prevent it by eating and drinking steadily from early in the ride.
