Not every bike can be used in Triathlon (see for yourself)

When starting triathlon it is always rewarding to do your first race. In my case, I started triathlon by registering for a very short triathlon ‘just for fun’. And I got worried I didn’t have the right bike for the event. So let’s clarify what’s allowed and not allowed in triathlon. But also, what kind of bike do you need for a triathlon?

The rules of triathlon are very permissive on the choice of bike for a triathlon. It is best to use a triathlon or TT bike if you wish for the most efficient time possible. A road bike is sufficient for most people and for a first triathlon any bike will do.

As long as it is allowed by the rules! Let’s review them below.

Do you need a special bike for a triathlon?

You don’t need a special bike for a triathlon. Any ‘normal’ looking bike will do. Some types of bikes are more efficient than others but the rules are quite permissive on the type of bike you can use. As long as your bike is not longer or wider than a normal bike, just be careful if you use very aero wheels, and you are good to go.

What bikes are allowed in a triathlon?

Bikes allowed in triathlon are:

  • TT bikes
  • Mountain bikes
  • Road bikes
  • Hybrid bikes
  • Gravel bikes
  • Cyclocross bikes
  • Triathlon bikes

In summary, all the ‘regular’ bikes with a free-wheeling mechanism, not unusually longer or wider than a standard bike, and without any means to proper itself. Therefore electrical bikes are prohibited. But I am sure you knew that already 😉

Bikes allowed VS not allowed in triathlon

Please note this list above applies to triathlons organized by World Triathlon, USAT, and Ironman.

Let’s dig into the rules from the most common event organizers. I have gathered in the tables below all the relevant information regarding bike specifications from World Triathlon, USAT, and Ironman competition rules.

Bike geometry approved in triathlon

Description * refer to imageWorld TriathlonUSATIronman
Bike overall length [E]*< 185 cm < 200 cm< 200 cm
Bike widthNot specified< 75 cm< 75 cm
Height between ground and center of the chain wheel axle [C]*24-30 cm> 24 cm> 24 cm
Distance between chain wheel axle and
center of the front wheel [D]*
54-65 cm54-65 cm54-65 cm
Saddle tip from center of the chain
wheel axle [A] & [B]*
– 15 cm / + 5 cm– 15 cm / + 5 cm– 15 cm / + 5 cm
Shields & FairingsProhibitedProhibitedProhibited
Type of frame allowedTraditional shapes,
diamond shapes,
UCI TT frames
Traditional shapes,
diamond shapes,
UCI TT frames
Not specified
Comparison of bike geometry approved between World Triathlon, USAT and Ironman

Wheel requirements for triathlon

FeatureWorld TriathlonUSATIronman
Any type of mechanism in the wheel that moves the bike forwardProhibitedProhibitedProhibited
Brake on each wheelMandatoryMandatoryMandatory
Disc BrakesAllowedAllowedAllowed
Number of spokes on wheelsMinimum 12Not specifiedNot specified
Disc wheels– Prohibited (draft legal races)
– Allowed for the rear wheel only (draft illegal races)
Allowed only on the rear wheelAllowed only on the rear wheel
(except at the Ironman World Championship)
Comparison of wheels requirements between World Triathlon, USAT, and Ironman

Other bike features and accessories specifications for triathlon

FeatureWorld TriathlonUSATIronman
Handlebar endsMust be pluggedMust be pluggedMust be plugged
Clip-on aero barsAllowed
(non-draft only)
(non-draft only)
Platform pedalsAllowedAllowedAllowed
MirrorsProhibitedProhibited Prohibited
Aero bottlesProhibited
behind saddle
for draft legal races
Free-wheeling mechanismNot specifiedMandatory
(no single speed bikes allowed)
(no single speed bikes allowed)
Comparison of bike features between World Triathlon, USAT and Ironman

Are disc brakes allowed in triathlon?

Disc brakes are allowed in triathlon whatever the organizer. Ironman, USAT, and World Triathlon all agree on this matter. It used to be banned in the past until 2018.

Can you use a regular bike for a triathlon?

You can use a regular bike for triathlon. The rules allow it. In XS and S triathlon events, there are generally several people who recently started triathlon and will participate using their regular bike. It is just not the best for speed but who cares.

Do you have to use a road bike for a triathlon?

You don’t have to use a road bike for a triathlon. It is the most common type of bike used by age group triathletes, as it is more versatile than a triathlon bike, and more affordable while still providing good aerodynamics. It is a good option for a triathlon.

A very common solution chosen by triathletes is to use a road bike and add clip-on aero bars to it. This will improve the performance of the bike. This is only possible in draft-illegal races which are the most common type of triathlon races.

If you want to know more about aero bars and understand the performance gain, I have quantified it in this article.

Can you do a triathlon on a hybrid bike?

You can do a triathlon on a hybrid bike. It is common for beginners to use whatever bike they have on their first race. If you care about performance and speed, make sure you have road tires (or slick tires) to reduce friction.

Depending on the type of hybrid bike you have, it can actually be quite similar to a road bike. Some hybrid bikes do not have suspensions and are quite light (around 10kg), making them quite efficient on the road. No shame in using an hybrid bike!

By the way, if you want to know if you need suspensions on a hybrid bike, outside of a triathlon event, I have written a dedicated article about it.

Can you use a gravel bike for a triathlon?

You can use a gravel bike for a triathlon. It will be a bit heavier than a road bike but it should not really affect your performance. A gravel bike will also be good if you have some bad tarmac on the course and pot holes.

What bikes are allowed in Ironman?

Ironman follows similar rules to USAT. That means almost all bikes are allowed except for recumbent bikes, bikes with a front disc wheel, or fixies. You can therefore race an Ironman with a TT, a gravel, or a hybrid, even if equipped with disc brakes. It’s much more permissive than UCI.

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