Aerodynamics of Time Trial Equipment: The Benefits of Helmets, Handlebars, and Skinsuits

Introduction

Time trials are known as the arena of equipment technology, with professional teams investing enormous resources in aerodynamic development every year. But for amateur riders, understanding the actual benefits of each piece of equipment is key to making the highest-return decisions within a limited budget. This article analyzes the aerodynamic contribution of each item, from helmets and TT bars to skinsuits.

Aerodynamic Equipment Benefit Ranking

Conclusions vary across different studies, but the general ranking of benefits is as follows:

Equipment Item	Estimated Speed Gain vs. Baseline (40km TT)	Cost Consideration
Riding position (not equipment)	3–5 km/h	Free, but requires time to adapt
TT bike	2–3 km/h	High (NT$150,000–600,000+)
TT helmet vs. road helmet	0.5–1.5 km/h	Low to medium (NT$5,000–25,000)
Skinsuit vs. loose jersey	0.5–1.0 km/h	Low (NT$3,000–10,000)
Overshoes	0.3–0.6 km/h	Very low (NT$500–2,000)
Aero helmet tail extension	0.2–0.4 km/h	None (included with TT helmet)
TT handlebars	0.3–0.5 km/h (mounted on a road bike)	Low (NT$2,000–8,000)

Choosing a TT Helmet

The Impact of Shape Design

Time trial helmets are designed to let air flow smoothly over the extended tail at the rear of the helmet, reducing turbulence behind the neck. The magnitude of the effect depends on head position:

• Head down (low position): Long-tail TT helmets work best, as the tail’s flow-guiding effect is fully utilized
• Head up (normal riding line of sight): The tail may “tilt up” and create additional drag; in this case, a rounder helmet is actually better

Buying advice: After putting on a TT helmet, simulate your time trial riding position and check that the helmet tail is roughly parallel to the extension line of your spine, rather than pointing upward.

The Ventilation Trade-off

Closed TT helmets have poor ventilation, and overheating during Taiwan’s summer races can hurt performance. In recent years, “vented TT helmets” (such as the Kask Bambino Pro and Giro Aerohead) have shown in testing that their aerodynamic performance is nearly identical to closed helmets, while offering better ventilation—making them suitable for Taiwan’s summer races.

TT Bars / Aerobars

Benefits of Mounting on a Road Bike

For riders using a road bike in time trials, adding clip-on aerobars is the most cost-effective aerodynamic improvement:

• Achieving a forward position: Allows the rider to adopt a forward-leaning position with elbow support, significantly reducing frontal area
• Installation focus: The length of the forearm extensions and the height of the elbow pads need careful adjustment (see time trial position setup)
• Taiwan regulation reminder: Some race rules prohibit clip-on TT bars in road races, while they are usually allowed in time trial events; check the race rules before use

Advantages of Integrated TT Handlebars

Time trial-specific bikes typically come with integrated handlebar systems, which offer advantages over clip-on bars:

• More coherent overall airflow: The handlebars, frame, and bottle cage are designed as an integrated unit, creating a smoother airflow path
• Better stiffness: More direct power transfer during pedaling
• Integrated braking: Brake levers are positioned at the ends of the extensions, so there is no need to move your hands

Skinsuits and Time Trial Suits

The Influence of Fabric

The difference between a skinsuit and a regular jersey is not just appearance, but material properties:

• Snug fit: Prevents loose jerseys from “ballooning” and creating extra drag while riding
• Smooth surface materials: Some high-end TT suits use materials with a “sharkskin” effect
• Minimized seams: Reduces turbulence generated by seams

Jersey Type	Relative Aerodynamic Drag	Comfort	Suitable Occasions
TT skinsuit	Lowest	Below average	Time trials, major events
Tight race jersey	Low	Moderate	Mass-start races, time trials
Standard race jersey	Medium	Good	Daily training, mass-start races
Loose training jersey	High	Best	Recreational riding

The Trade-off in Taiwan’s Summer

Ventilation in summer is a challenge for TT skinsuits. In Taiwan’s hot, humid summer time trials, many riders choose:

• Skinsuits with breathable mesh panels (such as mesh on the upper back)
• Or a high-quality tight race jersey instead of a pure TT suit
• Pairing with an ice vest to lower core temperature before the race

Other Aerodynamic Equipment Details

Overshoes

The ankles and shoe tops are areas with relatively large cross-sections that rotate at high speed. Overshoes cover protruding elements such as laces and dials, creating a smoother aerodynamic surface. In terms of cost-effectiveness, overshoes are “the cheapest speed gain” after position.

Bottle Cage Placement

A rear-mounted bottle cage (such as the Xlab Torpedo) places the bottle in a relatively “quiet” aerodynamic zone compared to a traditional down-tube cage, reducing interference with the overall airflow. In time trials, if you need to carry a bottle, a rear mount or an integrated design between the extensions is better than a fork-mounted cage.

Practical Advice

1. Position before equipment: Before investing in expensive TT equipment, spend time optimizing your riding position—it is the most effective and free speed gain.
2. Invest in stages: Start with a TT helmet and overshoes (highest value), then evaluate a skinsuit, and only finally consider a TT bike.
3. Rent and test: Some bike shops or rider communities offer TT equipment rentals; try before you buy.
4. Weight vs. aerodynamics: On flat time trials, prioritize aerodynamics; on hilly time trials, you need to balance aerodynamic equipment (weight) against weight reduction.

Conclusion

The aerodynamic benefits of time trial equipment are well documented, but for most amateur riders, the gains from position optimization still far exceed any equipment upgrade. After establishing a proper TT position, gradually upgrading aerodynamic equipment according to budget is the most cost-effective strategy. Taiwan’s time trial scene offers excellent opportunities for equipment testing, and every time trial is the best occasion to verify the return on your equipment investment.

Related Reading

• Optimizing Individual Time Trial (TT) Equipment: The Benefits of Aero Helmets
• Road Bike Aero Accessory Upgrades: Speed Gains from Aero Helmets, Skinsuits, and TT Bars
• Choosing Aero Kits for Olympic-Distance Triathlon Bikes: The Highest-Value Investment
• Optimizing Road Bike Time Trial (TT) Training: Aerodynamic Research on Power Output Strategies