What’s the difference between a triathlon bike and a road bike?

Triathlon bikes and road bikes are ridden in triathlons, but what is the difference and which you should choose for your event?

On the bike leg, about 75-80% of the drag comes from you rather than the bike so it’s vital that you’re in the most aero position possible. The best triathlon bikes are designed to help you become streamlined by positioning your torso level with the ground. This makes triathlon bikes a better option for 70.3 and Ironman triathlons.

But being lighter and more manoeuvrable, road bikes have the upper hand on mixed terrain. And their versatility makes them better for general training.

Triathlon bikes vs road bikes differences explained

We’ll outline the differences and similarities between triathlon bikes and road bikes by comparing their frames and components. Elsewhere, we set out the differences between triathlon bikes and time trial bikes.

Frame angles

A road bike has slacker frame angles than a tri bike and a higher front end. This gives you a more upright ride position until you shift to the drops and really bend your upper half over.

It’s the frame geometry that makes a triathlon bike different to a road bike as the aim is to get your upper body lower and further forwards. This not only makes you more aero but also opens up your hip-leg angle to make it easier to run off the bike.

Manufacturers give tri bikes a steeper seat angle (angle between seat tube and an imaginary straight line where the top tube meets the seat tube) than a road bike. Essentially, they move the saddle further forward in relation to the bottom bracket.

Frame tubes

Taking their design cues from the pro peloton, which has some strict equipment rules, most road bike tubes don’t slip through the air as well as those of triathlon bikes.

Some manufacturers are now offering more aero road bikes, though. These are usually the best road bikes for triathlon.

Seat post

The seatpost connects the saddle to road bike and triathlon bikes. It clamps into place at the top of the seat tube, but can be moved up and down to adjust height and allow for riders of different sizes.

Stem

The stem connects the handlebars to the steerer tube of the fork. This connection means that, when you turn the bars, the front wheel turns.

Hoods/shifters

If you’re ‘on the hoods’ on a road bike, you’ll be riding with your hands resting on the rubber covers on the shifters. Traditionally, on UK bikes, the right brake is the front and the left is the rear; the right shifter controls the rear derailleur and the left controls the front.

Brakes

Modern triathlon bikes, road bikes and time-trial bikes, almost always have disc brakes as opposed to old-fashioned rim brakes.

Rear derailleur

The rear derailleur moves the chain up and down the cassette.

Tops

When you’re riding with your hands on either side of a road bike stem, it’s called riding on the tops – a very popular position for climbing.

Drops

Drops are the part of the road bike handlebar that curves downwards. They allow the rider to assume a more aerodynamic position.

Tyres

Triathlon and time trial tyres are typically 23/25mm wide. But road bikes tyres have increased in width lately. 28mm has become standard and many road bikes have clearance for 32mm tyres, and wider.

Tyres come in clincher, road tubeless and tubular styles, depending on what sort of wheels you have.

Front derailleur

The front derailleur moves the chain between the two front rings common on a road bike. On flatter courses, some triathlon bikes will have a single chainring.

Wheels

Standard road bike wheels tend to be more durable and bulletproof than deep-rimmed aero wheels, so will usually feature a minimum of 20 spokes and minimal rim depth.

Aero wheels are usually made from carbon and come in a a variety of depths, most commonly between 45-90mm. You’ll see them on road and triathlon bikes.

Spokes

Both kinds of wheels have spokes joining hub to the rim. They pull the rim inwards at high tension, which makes the wheel extremely strong. If one loosens or breaks, it can imbalance the whole wheel.

Bull horns

These straight handlebars seen on triathlon bikes usually have small brake levers mounted on the end. (With electronic you’ll also find shifter switches.) Bull horns an be used when riding along or, more commonly, when out of the saddle to gain leverage.

On modern triathlon bikes, bull horns are sometimes called the base bar.

Extensions

You hold on to in order to maintain control when you’re in the aero position on a triathlon bike. If they have electronic shifters, you have buttons; traditional bar-end shifters are levers at the end of the extensions.

You can attach extensions to your handlebar to turn your road bike into a triathlon bike.

Arm rests

These are pads to rest your lower arms/elbows on when you’re on the extensions.

Rim

The rim is the edge of the wheel. On rim brake wheels, the upper part of it is the braking surface, where the brake blocks squeeze the rim in order to slow down.

The inner part connects the spokes to the hub.

Cassette

These days the cassette usually comprises 11 or 12 cogs are mounted on the freehub of the rear wheel. Shifting between sprockets changes the effort needed to move the bike.

On a road bike, the larger cogs will have more teeth, which makes it easier to pedal uphill.

Integrated brake

Older tri bikes have the brakes are integrated into the fork at the front, and hidden under the bottom bracket at the back to improve the aerodynamics of the bike.

Forks

On road bikes and triathlon bikes, the forks connect the front wheel to the handlebars. The steerer tube at the top of the fork goes through the head tube of the bike and is clamped by the stem, which allows you to turn the front wheel with your handlebars.