Tire Profile and Air Pressure

Tire Profiles Overview

The tire profile determines how the tire interacts with the ground. Depending on the application and terrain, different profile types are used.

Profile Types and Their Characteristics

Knob Arrangement and Performance

The arrangement of knobs significantly influences riding behavior:

001. Central Knob Row

• Low knobs in the center for low rolling resistance
• Ideal for straight riding on hard surfaces
• Reduces energy loss during acceleration

002. Side Shoulder Knobs

• Pronounced outer knobs for cornering grip
• Engage during lean and in corners
• Important for technical trails and singletracks

003. Knob Spacing

• Close spacing: Better grip on hard surfaces, higher rolling resistance
• Wide spacing: Self-cleaning in mud, lower grip on rock

004. Knob Shape

• Ramped: Better rolling behavior, lower braking resistance
• Block-shaped: Maximum braking grip, higher rolling resistance
• Mixed: Compromise for all-round use

Optimal Air Pressure

Air pressure is one of the most important and most frequently underestimated parameters in MTB tuning. It directly influences grip, comfort, puncture protection, and rolling resistance.

Basics of Air Pressure Selection

Recommended Pressure Ranges by Application

Factors for Pressure Adjustment

Rider Weight

• Light riders (under 70kg): -0.2 bar from standard values
• Medium riders (70-85kg): Standard values
• Heavy riders (over 85kg): +0.2 bar from standard values

Tire Width

• Narrow tires (2.0-2.3"): +0.1 to 0.2 bar
• Medium tires (2.3-2.5"): Standard values
• Wide tires (2.5-2.8"): -0.1 to 0.2 bar

Terrain

• Hard, smooth trails: +0.1 to 0.2 bar (less deformation needed)
• Rocky, technical trails: Standard values (compromise)
• Loose, sandy ground: -0.2 to 0.3 bar (more contact area)
• Roots and wet terrain: -0.1 to 0.2 bar (better adaptation)

Tubeless vs. Tube

• Tubeless: -0.2 to 0.4 bar possible (no pinch flat protection needed)
• With tube: Standard values or slightly higher (pinch flat protection)

Effects of Air Pressure on Performance

Too Low Air Pressure

Advantages:

• Maximum grip through large contact area
• Excellent damping and comfort
• Better traction when climbing
• Improved control in technical terrain

Disadvantages:

• Increased pinch flat risk (snake bites)
• Higher rolling resistance
• Poorer responsiveness
• Unstable handling in corners
• Increased tire wear on sidewalls

Too High Air Pressure

Advantages:

• Low rolling resistance
• Fast, direct responsiveness
• Reduced pinch flat risk
• Precise steering behavior

Disadvantages:

• Reduced grip due to small contact area
• Poorer damping, uncomfortable
• Increased slipping risk on loose surfaces
• Higher stress on rider and material

Front vs. Rear Wheel

Different pressures between front and rear wheel are important for optimal performance:

Front Wheel (lower pressure)

• More grip for steering and braking
• Better damping on obstacles
• Improved control on descents
• Typically: 0.2-0.3 bar less than rear

Rear Wheel (higher pressure)

• More pinch flat protection (carries main load)
• Better power transfer when starting
• More stable handling
• Less rolling resistance

Tubeless Systems and Air Pressure

Tubeless tires have significant advantages in pressure selection due to the absence of a tube:

001. Lower Minimum Pressure

• No pinch flat risk from pinched tube
• 0.2-0.4 bar less possible than with tube
• More grip and comfort

002. Self-Sealing

• Small holes are sealed by sealant
• Reduced puncture risk
• Important: Sufficient sealant (60-120ml depending on tire size)

003. Optimization Through Experimentation

• Start with manufacturer recommendation
• Gradually reduce by 0.1 bar
• Test on known trails
• Find personal optimum

Practical Tips for Air Pressure Adjustment

The Thumb Test (Rough Reference)

Although a pressure gauge is essential, the thumb test helps as a quick check:

• Too hard: Tire barely compresses (>3mm)
• Optimal: Tire gives 3-5mm under firm thumb pressure
• Too soft: Tire easily compresses 5-8mm

Seasonal Adjustments

Summer (high temperatures)

• Reduce pressure by 0.1-0.2 bar
• Reason: Heating increases pressure during riding
• Hardening ground often requires more grip

Winter (low temperatures)

• Increase pressure by 0.1-0.2 bar
• Reason: Cold reduces pressure
• Harder ground needs slightly higher pressure

Wet Conditions

• Reduce pressure by 0.1-0.3 bar
• More contact area for better grip
• Caution with tubeless: Not below minimum pressure

Tire Width and Air Pressure Relation

The wider the tire, the lower the pressure can be chosen to achieve the same contact area:

Common Mistakes and Their Solutions

001. Too high pressure for fear of pinch flats

• Problem: Loss of grip and comfort
• Solution: Gradually reduce, use tubeless

002. Same pressure front and rear

• Problem: Suboptimal handling
• Solution: Front wheel 0.2-0.3 bar lower

003. Pressure by feel instead of measurement

• Problem: Inconsistent performance
• Solution: Use digital pressure gauge

004. No adjustment to conditions

• Problem: Not optimal performance
• Solution: Adjust pressure depending on terrain and weather

005. Too infrequent pressure checks

• Problem: Gradual pressure loss unnoticed
• Solution: Check before every ride, especially with tubeless

Last updated: November 12, 2025