Tri Bikes vs Road Bikes

In this article, we look at one of the biggest quandries for the new triathlete - understanding the difference between a tri bike and a road bike and whether putting clip-on aerobars on a road bike achieves the same result.
Created: May 2011
Revised: August 2011
Latest Feedback: November 2013

Introduction

Overall, the essential advantage of a triathlon specific bike is that it is purpose-designed for a multisport athlete who requires optimal energy efficiency during the cycle leg in order to keep the legs fresh for running later. To understand how that is achieved, and without getting too technical or confusing, let’s break it down to the main features.

Aero Bars

Firstly, a tri-bike is built around the concept of the aerobar, where a large amount of the rider’s weight is supported on their forearms “resting” on the armpads of the aerobar. This position is radically different to the road bike position where muscular effort is used to support the weight of your torso on the handlebars, and the overall centre of gravity is further to the rear of the bike. But, this is not the only difference between a tri-bike and a road bike yet many people do in fact simply modify their road bikes by adding clip-on aerobars to their road bikes.

The problem with adding aerobars to a road bike is that you change your riding position in two critical ways that affect performance. Firstly, the upper torso becomes more stretched out – arms and elbows are further forward. Secondly the angle between the top of your thigh and your torso at the top of the pedal stroke is more acute and you’ll feel cramped. For some people this will also create problems with breathing efficiency and the glutes and hamstrings become strained resulting in a less powerful contraction. Lower back pain and saddle discomfort are also typical problems caused by this modification to the road bike.

The tri-specific bike is designed to eliminate these body mechanic issues. The tri-bike geometry is fairly generic between all manufacturers (give or take a little for design and materials) because the frame is purpose-built on the assumption that the rider is in the forward, and narrow aerodynamic position. See the final section on Bike Fit for more information.

Tri Bike vs Road Bike Geometry

The geometry of the tri bike will usually consist of a steeper seat tube angle, a less aggressive head tube angle, a slightly shorter top tube, and a lower front end, with a shorter chain stay.

The tri-bike frame measurements are designed so that when the rider is in the aero position, the hips remain open to ease tension in the legs and lower back, make breathing easier, and reduce fatigue.

This improvement in cycling efficiency over long distance becomes most apparent when you transition from bike to run with a much easier feeling in the legs.

Training

In the training environment, triathletes often combine sessions of running immediately after cycling called Brick Sessions. On these rides, as in racing, a tri-specific bike is going to aid in your comfort and efficiency and set you up for a better running session.

However, triathlon frames are not intended for use in group rides which typically involve drafting, roundabouts, and fast cornering. Aerobars are dangerous in these situations because the rider cannot easily jump on the brakes. Tri-bikes do not corner as tightly as a road bike and are generally less easy to handle in sudden evasive manoeuvres, which make them less safe for a tight group ride in a suburban environment. In fact, most cycle groups will not allow riders to use aerobars, and may even refuse riders on tri-bikes. If you are on a solo ride, or non-drafting smaller group ride then training on a tri-bike or with aero bars isn’t a problem.

It should also be noted however, that many coaches also encourage triathletes to ride frequently without using a tri-bike to ensure training is also performed using the leg muscles that are engaged in the road bike position. This makes for a stronger rider overall. So ideally, a triathlete can make good use of both a road bike and tri-bike on a regular basis.

Performance

A tri bike will only outperform a road bike if the tri bike is correctly setup to fit the rider and the rider is comfortable and able to hold the aero position on the tri-bars for the majority of the ride. As soon as the rider "sits up" on a tri bike, all advantages of the tri bike are negligible.

So, whether you are racing or training, the decision between which bike or setup is right for you, really comes down to if it is practical or comfortable to be using the aero bars.

Bike Fit

The exact setup of your tri-bike can be modified to suit your individual body physique as every each rider will have varying amounts of flexibility, strength, and power as well as old injuries and other unique body mechanics that can be factored into the final adjustments to obtain the most ergonomic bike fit.

Many bike shops will offer an initial bike fit service when you buy a new bike, however this is unlikely to be the type of ergonomic bike fit we’re talking about here. In fact, if you can find a good bike fit specialist who has no commercial affiliation with a bike shop, it will pay to get all your measurements and optimal bike fit done before you make a selection of which tri-bike to purchase. This is because the bike fitting expert will take into account your requirement to not just be fast on the bike, but to also be able to run after your ride.

A good bike fit expert can give you a clear picture of what to look for in the tri-bike frame measurements and may even suggest which manufacturers frames are going to be the better fit for you. This is because bike manufacturers tend to have their own preference for Stack and Reach ratios, which means some individuals can be better suited to some brands and vice versa.

Expect to pay around $150 for a full bike fitting service - with initial consultation and measurements taken in your first visit, then a followup visit once you've bought a bike to have the actual bike setup done for you. This investment could save you thousands on buying the wrong bike that cannot be setup to fit you correctly without spending additional money replacement parts to make compromises.

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Article Tags

Tri Bike, Aerobars, Bike Fit, Tri Bike Geometry, Tri-Specific Bike, Tt Bike, Triathlon Bike

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