Fixed Gear

The fixed gear (German: Fester Gang) is the most characteristic feature of track bikes and fundamentally distinguishes them from road racing bikes. With a fixed gear, the rear wheel is rigidly connected to the drivetrain, so the pedals always rotate in the same rhythm as the rear wheel. This mechanical design has far-reaching consequences for riding technique, efficiency, and safety on the velodrome.

How Fixed Gear Works

Mechanical Fundamentals

Unlike freewheel systems on road bikes, the fixed gear has the cog firmly attached to the hub. There is no freewheel mechanism that would allow the pedals to remain stationary while the wheel continues to rotate. This rigid connection means:

• No coasting: The pedals always rotate when the wheel rotates
• Active control: The rider can brake by applying counter-pressure on the pedals
• Permanent connection: Every movement of the wheel is directly transmitted to the pedals
• Mechanical simplicity: Fewer moving parts mean less wear

Technical Construction

The fixed gear consists of several precisely coordinated components:

Advantages and Disadvantages of Fixed Gear

Advantages

Maximum Efficiency
The direct power transmission without freewheel enables an efficiency of nearly 100%. Every pedal movement is immediately converted into forward motion without mechanical losses from freewheel bodies or pawls.

Precise Control
Track cyclists can control their position on the track with millimeter precision through the permanent connection to the pedals. This is particularly crucial in sprint duels and in the banking.

Reduced Weight
The absence of brakes, gears, and freewheel makes track bikes significantly lighter than road racing bikes. A sprint bike often weighs under 7 kg, an endurance bike under 8 kg.

Low Maintenance
Fewer moving parts mean less wear and lower maintenance requirements. The chain only needs to be correctly tensioned and regularly cleaned.

Improved Riding Technique
Training with fixed gear promotes a smooth, even pedaling motion and improves coordination between both legs.

Disadvantages

No adaptation to course profile
The lack of gears means the gear ratio is fixed for the entire course. For different requirements (e.g., sprint vs. pursuit), the cog must be changed.

High demands on riding technique
Riding with fixed gear requires practice and experience. Beginners must first get used to the permanent pedaling motion.

Limited braking options
Braking by counter-pressure on the pedals is less effective than classic brakes. However, this is not a problem on the velodrome, as braking maneuvers rarely occur.

Gear Ratios for Different Disciplines

The choice of the right gear ratio is crucial for success on the track. It is determined by the ratio between chainring teeth and cog teeth.

Sprint Disciplines

Endurance Disciplines

Calculation of Development

Development indicates how many meters the bike travels per pedal revolution:

Formula:
Development (m) = (Chainring teeth / Cog teeth) × Wheel circumference (m)

Example:

• Chainring: 54 teeth
• Cog: 14 teeth
• Wheel circumference: 2.13 m (with 700c wheels)
• Development = (54 / 14) × 2.13 = 8.2 m

At a cadence of 120 rpm, the rider achieves a speed of:
8.2 m × 120 = 984 m/min = 59 km/h

Cog Change and Adjustment

When is a cog change necessary?

• Switching between sprint and endurance training
• Adaptation to different course lengths
• Optimization after performance diagnostics
• Consideration of track altitude
• Individual adaptation to cadence preferences

Performing the Cog Change

Required tools:

• Chain whip
• Cog remover
• Torque wrench

Procedure:

1. Remove rear wheel
2. Fix old cog with chain whip and loosen
3. Screw on new cog (torque: 40-50 Nm)
4. Check chain for correct tension
5. Test ride for verification

Chain Tension with Fixed Gear

Correct chain tension is particularly important with fixed gear, as the chain is permanently under load.

Optimal Tension

Guideline: The chain should have 10-15 mm play in the middle between chainring and cog.

Too tight:

• Increased wear on chain and cogs
• Higher rolling resistance
• Risk of chain breakage under peak loads
• Stress on bearings

Too loose:

• Risk of chain coming off in banking
• Unsteady running
• Inefficient power transmission
• Rattling noises

Adjusting Chain Tension

Tension is adjusted via horizontal dropouts on the frame. By shifting the rear axle forward or backward, tension can be precisely adjusted.

Braking with Fixed Gear

Physical Fundamentals

When braking with fixed gear, counter-pressure is applied to the pedals. Braking force is determined by leg muscle power and gear ratio. The larger the gear ratio, the higher the possible braking force.

Braking Technique

Controlled deceleration:

• Even counter-pressure on both pedals
• Shift body weight backward
• Keep upper body upright
• Look forward

Emergency brake:

• Maximum counter-pressure
• Body far back
• If necessary: Short block by fixing pedals
• Caution: Risk of flipping over!

Training with Fixed Gear

Advantages for Riding Technique

Training with fixed gear has been proven to improve various aspects of riding technique:

Pedaling Optimization:

• More even power distribution over the entire pedal cycle
• Better coordination between left and right leg
• Reduction of dead spots in pedaling motion

Cardiovascular Training:

• Constant load without recovery phases
• Improved lactate tolerance
• Higher average heart rate

Muscular Adaptations:

• Strengthening of rear leg muscles (hamstrings)
• Improved core stability
• Higher maximum strength

Specific Training Units

UCI Regulations on Fixed Gear

The Union Cycliste Internationale (UCI) has clear regulations for fixed gear in track racing:

Mandatory Regulations:

• Fixed gear is mandatory for all track competitions
• No freewheel mechanisms allowed
• No brakes on the bike allowed (except for juniors)
• Cog must be firmly bolted to hub
• Lock washer must be used

Technical Control:

• Inspection by commissaires before every competition
• Test of rigid connection between cog and wheel
• Check of chain tension
• Safety check of bolting

Materials Science and Innovation

Modern Cog Technology

Steel Cog:

• Highest durability
• Heavier than alternatives
• Affordable purchase
• Standard for training

Aluminum Cog:

• Significantly lighter than steel
• Shorter lifespan
• Medium price level
• Ideal for competitions

Titanium Cog:

• Optimal weight-strength ratio
• Very long durability
• High price
• Premium option

Chain Development

Modern track chains are specifically designed for the high loads of fixed gear:

• Reinforced links: Higher tensile strength
• Optimized lubrication: Reduced wear
• Precision manufacturing: Minimal play between links
• Special coatings: Corrosion protection and efficiency

Common Problems and Solutions

Cog comes loose

Causes:

• Insufficient torque
• Missing lock washer
• Worn threads

Solutions:

• Use torque wrench (40-50 Nm)
• Always mount lock washer
• Regularly check threads

Chain comes off

Causes:

• Too loose chain tension
• Worn chain or cog
• Crooked chain line

Solutions:

• Correct chain tension
• Replace worn parts
• Check chain line

Unsteady running

Causes:

• Eccentric mounting of cog
• Bent chainring
• Warped rear wheel

Solutions:

• Dismantle cog and recenter
• Check chainring for true running
• Have wheel trued