It used to be said, “Go as deep as you can handle in the conditions.” FLO previously recommend our 90 mm deep front wheel to heavier, experienced athletes. However, advanced engineering has now allowed us to create a 77mm deep section rim that is faster than our previous 90mm wheel. As FLO has led the way in understanding aerodynamics, rolling resistance, road vibration, real-world wind yaw, and other key factors, we’ve applied these gleanings to our carbon wheel design.

The introduction of the AS 77 means you get more speed with less fear of being blown about because of a faster design with a shallower depth.

Why not a disc front on my tri bike?

Maybe you’ve watched an Olympic track event on a velodrome and thought, “I should try a disc on my front like they do. After all, isn’t the front wheel the one causing the most drag?”

While a front disc would technically be the fastest in a lab setting, we would never recommend a front disc in a real-world, outdoor setting. Why? With any crosswinds, a triathlon bike would be unrideable. Since the front wheel is mounted to a rotating fork to allow the rider to turn, a steering axis is created. This steering axis causes the front wheel to be much more reactive to wind gusts than a rear wheel.

Summary: Don’t go deeper than you can handle in crosswinds.

Rear Selection

A rear wheel will not react in the same way as a front-wheel because it is fixed in the frame without a steering axis. A rear wheel will only move as much as the rest of the bike does when subject to side forces. You can get away with much greater depth wheels for the rear than you can the front.

Rear Disc for Tri’s

This back-wheel-is-affected-much-less principle is why you’ll see many elite and age group triathletes riding a rear disc wheel. In almost every situation, a rear disc is the fastest means to get from point A to point B. The only situation where this isn’t true is if there are insane crosswinds (35 mph). Because of unpredictable crosswinds, a few races don’t allow discs for this reason. The famed Kona race is one of these. However, most triathlons DO allow disc rear wheels to be used.

We realize that some FLO riders will use the same rear-wheel for road racing/riding events. If you seek a wheel that is fast but can be used in both TRI and ROAD racing/rallies, consider the AS 77 rear or A+C90 as your best contenders.

Summary: If you are going to go disc or extremely deep rimmed, do so in the back.

Whether racing sprint, Olympic distance, half Ironman, or full Ironman triathlons, we all want to be as fast as possible on the bike leg. Efficiency on the bike leg is crucial for a successful run and a better time. Efficiency requires going as fast as possible for the least number of watts. This article will help you select the best wheels for your tri bike upgrade.

What Makes Picking Carbon Wheels for Your Triathlon Bike Different than Road Bike Wheels?

Road cyclists are often obsessed with being lightweight. A road race cycling course will often have more vertical feet of climbing than a tri course. In addition, the ability to draft off other riders in road races allows these weight considerations to become more central as aero advantages are gained from drafting. While aerodynamics still matter more than weight for roadies, for triathletes who cannot draft and race on courses that rarely ascend Alpe d’Huez types of climbs, aero is KING.

A second consideration for road cyclists is the high variability of pace in a racing scenario. Unlike tri’s where athletes seek to lay down consistent power, road races have surges in speeds, breakaways, and sprint efforts. Roadies have a goal of staying connected to the rider in front of them at almost any cost. This is where a lightweight wheel’s superior acceleration is needed in a way that is not relevant to triathlon. If you are accelerating and decelerating throughout the bike leg in a tri or duathlon, you will be in big trouble come final run time. Road bikes have different criteria for success than a fast tri machine!

In addition, for triathletes bike handling is a consideration. Staying down in the aero bars is crucial. The frame geometry and rider position on a triathlon bike result in them being less responsive than an aggressive road setup. If you fear with how the bike is handling, you’ll often come out of an aero position. This will slow you down much more than any time you will gain from a fast wheelset. But as you improve your handling skills, gain confidence, and can thus stay lower in different wind conditions, a set of carbon triathlon wheels will absolutely make you faster. In fact, FLO’s testing shows a savings of over 6.5 minutes in an Ironman length event versus standard Mavic open wheels. Without an optimized wheelset, you’ll have to run 20 seconds per mile faster for EVERY mile on the marathon leg to make up that time. That’s huge come race day!

What is braking performance like with carbon wheels?

A huge part of racing success and safety is the ability for the rider to stop a bike effectively and efficiently. Riding in a peloton requires feathering the brakes for drafting and abrupt stops to avoid a crash ahead. Descending presents its own unique braking needs, as the fastest descenders minimize scrubbing speed, but when they need to, it’s crucial their brakes work so they don’t overshoot a turn. Even triathletes and time trialists need solid stopping power for sharp turns, road obstacles, and other occurrences.

Rim Brakes

A longtime concern about all-carbon rimmed wheels is their braking power. When rim brakes were the main type of braking system on high-end bikes and the UCI outlawed disc brakes, the concern was even greater. This is because a rim brake works by having a caliper with pads that squeezes against the surface of the rim.

When this pad comes into contact with carbon, there is a concern about the amount of friction needed to stop and the corresponding wear and heat upon the rim. One option is to create a carbon wheel with aluminum brake to provide the pad a non-carbon contact point. This prevents wear of the brake track, but it does not fully alleviate the heat concerns. However, recent development in carbon technologies allow for all carbon rims that can be used in combination with rim brakes as long as the brake pads are specifically designed for carbon rims. This new carbon resists wear and better handles heat. Some riders, including Chris Froome and other pros, still prefer rim brakes for rapid in-competition wheel changes and fewer problems with disc brake rub because of misalignment. Rim brakes typically are shown to be more aerodynamic in wind tunnel tests, as a bonus. However, more and more bike manufactures are moving towards disc brakes, which means wheel manufacturers must follow.

Disc Brakes

The newest trend in braking allows riders to stop without a brake pad having to touch the rim. Disc brakes, instead, have a metal rotor that is at the center of the wheel, connected to the hub.

The pressure of a piston is applied to this metal disc instead of the rim surface, in order to provide braking power. This alleviates concerns about rim wear and overheating issues (see safety section below for more on rim overheating). They also stop a rider faster than a rim brake. This is especially true when conditions are wet. The UCI and other governing bodies now allow for disc brakes in competition. Disc brakes offer greater stopping power, which can be helpful on long descents, and they allow for more precise braking, making wheel lockup less likely. It’s also easier to use wider tires with disc brakes and the frame is the only limiter, not the brake caliper width capabilities.