Triathlon Bike Size Chart – UPDATED 2021 – A Complete Guide!

When buying your first triathlon bike looking for the correct triathlon bike size chart is sometimes forgotten. Triathlon bikes are free to roam from the UCI rules which follow stringent guidelines. And now seeing more manufacturers move towards more radical designs and shapes to cheat the wind.
While the design of tri bikes are focused around aero gains, manufacturers are now making these bikes fit a wider range of people. This is where choosing the correct bike becomes more important than ever and why these manufacturers specify a triathlon bike size chart with each model.

Before you jump on the internet and start shopping for a tri bike, it is important to know what distance triathlons you are competing in. For events such as the sprint and Olympic distance, aerodynamics plays an important role for the age grouper. Unlike the Ironman distance, there is no need to carry extra water or nutrition on the bike. this means you can look into a TT bike rather than just a triathlon bike.

If you are competing in a Half Ironman or Ironman, Both aerodynamics and storage play a big part in choosing the correct tri bike. Below we talk about triathlon bike measurements and picking your first triathlon bike.

What Size Triathlon Bike Should You Buy?

To get the correct sizing of your triathlon bike, it is always important to test the bike. All bicycle brands offer different models and are aimed at different levels of triathletes and markets. Since you have many different models on the market, this means each brand measures there frames differently. So a 52cm frame in one brand may be a different measurement in another.

So what size triathlon bike should i buy? Your tri position is based on a few factors. How flexible are you? and How long is your event? These two questions provide important answers to picking the right size triathlon bike. Your position needs to be comfortable enough for the duration of the event or and the distance you ride for. But for beginners, it may be uncomfortable even though you are set up in the correct position.

Most cities have reputable bike fitters that have a proven record. It’s worth spending the money to get measured up and have your mobility checked before you spend thousands on a tri bike.So it is important to consult with a bike fitter in your area if you are unsure of your measurements or your flexibility.

Triathlon Bike Fit Measurements

All road, TT and triathlon bikes are sized in centimeters, but often you see companies such as Giant labeling them as small, medium, and large. Don’t let this confuse you, as most triathlon bike fit measurements are provided in the detailed description of the bike.

To measure a tri bike start from the center of the bottom bracket and measure to the center top of the seat tube. You must also note that some manufacturers measure from the center of the bottom bracket to the center top of the seat tube. So check this with the manufacturer.

Two other important triathlon bike fit measurements are the top tube and head tube of the bike. To measure the top tube, measure from the center of the seat tube to the center of the head tube horizontally. The head tube is relatively easy, with measuring from the bottom to the top of the head tube.

These three measurements are extremely important when purchasing a triathlon bike. Understand your inseam length, and lower back flexibility are important factors to consider. Lower back flexibility often tells us the head tube size of the bike we need. While the inseam length tells us the seat tube length.

To get a rough idea of the frame size you can measure you inside leg (in centimeters) and then multiply by 0.65. So for example, if you have an inside leg length of 80cm this would put you on a 52cm frame size (80×0.65). While this gives you a ballpark figure, you might find you are between sizes. This is where the head tube and top tube length come into play. If you have good lower back flexibility, you can move to the smaller frame. But this can also depend on the manufacturer and how the bar setup is.

Triathlon Bike Size By Height – What You Should Know?

Triathlon bikes are designed for speed and why there are so many features. From TT bars to aero wheels and aero design.  To get the most comfortable and aerodynamic riding position it is important to get the right size. If you are racing half Ironman or Ironman its event more important since you are spending more hours in the aero position. But don’t rely entirely on picking your triathlon bike size by height as there are many other factors that come into play. The proportion of you body determines a lot to do with the size of the bike, as well as other factors we have talked about.  So picking a triathlon bike by your height is a good starting point, then look into other factors such as you leg length, flexibility and mobility. Taking this approach will save you thousands of dollars in the long term.

Triathlon Bike Size Chart – UPDATED 2021

Below this triathlon bike size chart gives you an estimated size frame based on your height. Make sure you measure your height accurately and also take into account your flexibility and other measurements we have spoken about.
Triathlon Bike Size By Height – What You Should Know?

Feet & Inches	Centimetres	Frame Size (cm)	Frame Size
4’10” – 5’0″	148cm – 152cm	47cm – 48cm	XX-Small
5’0″ – 5’3″	152cm – 160cm	49cm – 50cm	X-Small
5’3″ – 5’6″	160cm – 168cm	51cm – 53cm	Small
5’6″ – 5’9″	168cm – 175cm	54cm – 55cm	Medium
5’9″ – 6’0″	175cm – 183cm	56cm – 58cm	Large
6’0″ – 6’3″	183cm – 191cm	58cm – 60cm	X-Large
6’3″ – 6’6″	191cm – 198cm	61cm – 63cm	XX-Large

Time Trial Frame Sizing

If you put a triathlon bike next to a time trial bike, for the untrained eye it’s hard to spot the difference. They look identical and both with aerodynamic tubing and aerobars.

Time trial frame sizing is quite different from triathlon frame sizing. Triathlon bikes typically (not always) have steeper seat tube angles. This allows the hips to roll forward and keeps the hamstrings from overworking.

Your typical time trial races are less distance than the triathlete on the bike. This means often time trialists go for a more aggressive position and go for the smaller recommended frame size in the time trial frame sizing chart.