Things You'll Need:
- Road Bicycle or Time Trial Bicycle
- Shallow Profile Road Wheels
- Semi Aero Road Wheels
- Deep Aero Road Wheels
- Super Deep Aero Road Wheels
- Carbon Spoke Aero Road Wheels
- Disc Road Wheels
- A Time Trial Event
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Step 1
Time Trial Events are a special type of bicycle racing wherein competitors race against the clock on a predetermined course. The rider with the fastest time wins the event. Since time trials are raced individually the greatest resistance experienced by the rider is wind resistance. The key to winning a time trial event is to maximize aerodynamic efficiency of the bicycle and rider while producing maximum power throughout the event. The wheels for this type of event have come to be highly specialized and diverse.
Different wheel profiles have different strengths and weaknesses. Understanding the differences of each profile will help when selecting the best option for time trial events.
Shallow Profile Wheels are the lightest in terms of weight. These are really only suited for uphill time trials when the anticipated maximum speed will be less than 18 miles per hour (the speed at which wind resistance overtakes mechanical resistance). These wheels are the least affected by windy conditions.
Semi Aero Wheels are typically 30-40mm deep in profile. The purpose of these wheels is to provide some aerodynamic benefits in a lightweight package thus blending the characteristics of a deep aero wheel with a shallow profile wheel. These wheels are partially affected by windy conditions.
Deep Aero Wheels are typically 45-60mm deep in profile and provide good aerodynamics for some time trial events. The handling characteristics of the bicycle are affected by windy conditions with these wheels. The aerodynamic benefits tend to outweigh this drawback.
Super Deep Aero Wheels are typically greater than 80 mm deep in profile and provide the best aerodynamics for a traditional spoke wheel in time trial events. The handling characteristics of the bicycle are affected by windy conditions with these wheels. The aerodynamic benefits tend to outweigh this drawback.
Carbon Spoke Aero Wheels are wheels typically constructed of carbon fiber featuring three, four, five, or six carbon spokes to reduce wind drag. The handling characteristics of the bicycle are affected by windy conditions with these wheels. The aerodynamic benefits tend to outweigh this drawback
Disc Wheels are wheels that present a solid surface to the wind (IE there are no open voids between the rim and the hub). These are the most aerodynamic wheels available however they are the most influenced by crosswinds. They are typically only used on the rear wheel. -
Step 2
Pre-ride the course that will be used for the time trial race. While riding the course keep a count of the number of corners, hills, flats, and false flats there are. Also pay close attention to the environmental conditions like the road surface, wind speed and wind angles.
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Step 3
For an uphill time trial the greatest concern is typically weight. If during your pre-ride you were unable to maintain a speed greater than 18 miles per hour for more than 50% of the time then a lightweight shallow profile wheel would be the best option for this event. If, however you were able to maintain speeds above 18 miles per hour than a lightweight semi aero wheel would be a more an advantageous equipment selection.
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Step 4
For a time trial event with a mix of both climbing and flat sections equipment selection will be based on which there is more of and the average speed you will be able to maintain. If the course has more climbing than flat sections a semi aero wheel would be more suitable. If the course has more flat sections than climbing a deep aero wheel would be more suitable. Generally speaking the higher the estimated average speed is the more aerodynamic your equipment selection needs to be.
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Step 5
For a mostly flat time trial the greatest concern is aerodynamics. Since the nature of this race requires the rider to go as hard as possible and as aerodynamically as possible the logical choice would be to equip the bike with disc wheels. However, because a front disc wheel is extremely difficult to control in even slight crosswinds the better choice would be a rear disc wheel and a front wheel that is either a carbon spoke aero wheel or a super deep aero wheel.
If conditions are so windy that control of the bicycle begins to outweigh the aerodynamic advantages of the rear disc wheel than the wheel should be replaced with either a carbon spoke aero wheel or a super deep aero wheel to match the front.
