Using a Mountain or Commuter Bike in a Triathlon?

One of the more common questions we get from beginner triathletes is if they can use their mountain bike, commuter bike, or hybrid bike in the triathlon.  The answer is yes, absolutely – especially if you are doing a sprint or perhaps even an Olympic distance.

It can be tempting when starting a new sport, to run out and buy all the awesome gear you see the professionals using.  You wonder if you will be taken seriously if you are not rocking the right equipment. However, making huge purchases for something you may not take up as a serious hobby can be a costly mistake.  If you have the budget to invest in an entry level road bike, take a serious look at doing so because you undoubtedly will use the road bike far beyond the triathlon.  If you don’t have easy access to that kind of budget – and most of us don’t — It is best to hold back until you have done a tri or two and have discovered whether you have a passion for it.

When considering competing in their first triathlon, most people wonder if they can use the bike they already own. The short answer is: Yes! There is no judgment based on having the “right” cycle. All types of bikes can be found in these races, as most people are racing only for fun and exercise. Unless you are at the Half Iron or Ironman level, it is guaranteed you will not be the only rider on an average cycle. Cruisers, road bikes, and everything other type will be there. Most of us have a mountain bike stored in our garage somewhere that we could use. So, here are a few tips to get it ready to race:

Street Tires or “Slicks”

vittoria slick mtb triathlon

Vittoria Street Runner Slick

Mountain bikes are made to conquer rough terrain and grip in places without solid footing.  As a result, there is lots of contact between the rubber and the ground – more than you need on pavement.  In a tri, it is a good idea to replace the knobby tires with a more road-ready option. Grab a tire that is smooth in order to minimize resistance on the street and maximize speed – these tires are commonly known as “slicks”.  Street tires are the #1 rcommended modification for anyone taking a mountain bike into a triathlon, and the good news is that doing so will cost you less than $50.  All the other upgrades listed in this article can wait, or be bypassed completely by purchasing a tri-bike when you are ready to step up to the next level.

Recommended: The Vittoria Street Runner (pictured) is a great all-around slick that won’t break the bank.

Clipless Pedals

High-end pedals are not a necessity, but if you want to see how fast you can race and compete, they are definitely worth considering.  There is a good chance you already have some type of clipped or clipless pedals on your bike. Basic pedals are fine for casual riding, but an upgrade will make a big difference in your times. Clipless pedals provide more stroke control and allow you to get power from the entire 360 degree rotation of each pedal stroke. They are coupled with shoes that snap onto the pedal quickly and lock your feet into position. These connect the rider to the bike, making for tighter turns, better handling, and consistent pedaling. Clipless pedals are certainly a worthwhile investment once you begin the transition into a serious competitor.  They are easily installed on any bike either at home or in just a few minutes at a bike shop.

Seat / Saddle Replacement

Your bike seat is one part of the bike that is entirely personal preference. However, it is an opportunity to shave some weight off your ride, and also position yourself for speed versus mobility and comfort, which is how many mountain bikes come from the factory. The decision on which saddle is right for you depends entirely on what is most functional and comfortable for your rear end. Go with what works for you, as we all have different needs. The only advice in this area for using a mountain bike in a triathlon is raising the seat level to gain a higher stance. This allows better positioning for speed.

Aero Bars

Adding clip-on aero bars to your MTB handlebar is another option that you will see some racers do, but we don’t recommend it.  The aero bars on a triathlon bike are designed for perfect body positioning in relation to a tri bike frame.  A mountain bike has fundamentally different frame angles, and you aren’t going to change that. Some riders swear that bull-horns, or aero bars, make reductions in drag due to aerodynamics.  We say that if you are going to so this far with your bike, just consider an entry-level road or tri bike.


Adjusting the suspension on your mountain bike is a free adaptation that will help as well. Tighten your springs as much as possible or lock them in stiff if your bike is able. The flexibility of the springs helps in rough areas but hinders speed and control in a street riding scenario.  You don’t need any suspension at all while racing in a triathlon. The cycling arm of a triathlon should be a smooth ride, so bypass the suspension and glide.


One important thing to note is that the gearing of a mountain bike is fundamentally different than that of a road or tri bike.  Mountain bike gears are not meant to cruise at high road speeds – they are meant to be responsive in technically challenging conditions.  Even a perfectly-outfitted mountain bike will be a couple miles-per-hour slower than the same ride on a road or tri bike.

Entering a triathlon for the first time can be an exciting experience. The most important thing to remember is not everyone is there for the competition. Most entrants are only concerned with having fun and racing against their own best times. Enjoy yourself and do not be concerned early on about having all the right gear. You always have the option of buying the professional equipment later to help your times, but at first, just relax and revel in the new adventure.

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