Trek Bike Suspension Calculator
Optimize your Trek bike's suspension settings by entering your details below.
List of the Top 10 Best Trek Bike Accessories:
Complete Guide to Mountain Bike Suspension Setup
Understanding and properly setting up your bike's suspension is crucial for optimal performance, comfort, and safety. This comprehensive guide will help you master the fundamentals and fine-tune your suspension for the perfect ride.
Understanding Suspension Basics
Modern mountain bike suspension systems are sophisticated pieces of equipment that serve multiple purposes:
- Absorbing terrain impacts to maintain control and reduce rider fatigue
- Maintaining tire contact with the ground for better traction
- Supporting rider weight and preventing excessive suspension movement during pedaling
- Helping the bike maintain its intended geometry under dynamic conditions
Key Suspension Components and Terms
| Component/Term | Description | Impact on Performance |
|---|---|---|
| Air Spring | Compressed air that provides the main suspension force | Determines how supportive and progressive the suspension feels |
| Coil Spring | Metal spring providing consistent suspension force | Offers more sensitive small-bump response than air springs |
| Rebound Damping | Controls how quickly suspension returns after compression | Affects bike stability and traction |
| Compression Damping | Controls suspension resistance to compression | Influences support and bottom-out resistance |
| Volume Spacers | Tokens that adjust air spring progression | Changes how suspension resists bottom-out |
Understanding Suspension Travel
Different riding disciplines require different amounts of suspension travel. Here's a breakdown of typical travel ranges and their best uses:
| Travel Range | Typical Use | Characteristics |
|---|---|---|
| 100-120mm | Cross Country | Efficient pedaling, lightweight, quick handling |
| 130-150mm | Trail | Versatile, balanced between efficiency and capability |
| 160-180mm | Enduro | Focused on descending performance while maintaining climbing ability |
| 190-200mm | Downhill | Maximum impact absorption, descent-oriented geometry |
Detailed Guide to Suspension Settings
1. Air Pressure and Sag Setup
Sag is the foundation of suspension setup. It represents how much your suspension compresses under static load (your body weight in riding position). Proper sag ensures your suspension can extend into holes and compress over bumps effectively.
| Riding Style | Fork Sag | Shock Sag | Considerations |
|---|---|---|---|
| Cross Country | 15-20% | 25-30% | Firmer for efficiency |
| Trail | 20-25% | 25-30% | Balanced for versatility |
| Enduro | 25-30% | 30-35% | Softer for big hits |
| Downhill | 30-35% | 30-35% | Maximum absorption |
2. Understanding Volume Spacers
Volume spacers (also called tokens or volume reducers) are used to adjust the progression rate of air springs. They affect how the suspension behaves in the latter part of its travel:
- More spacers = More progressive feel, harder to bottom out
- Fewer spacers = More linear feel, easier to use full travel
- Helpful for tuning suspension to rider weight and style
- Can be adjusted without changing other settings
Recommended Volume Spacer Settings
| Riding Style | Rider Weight | Fork Spacers | Shock Spacers |
|---|---|---|---|
| XC/Trail | Light (<150lbs) | 0-1 | 0-1 |
| XC/Trail | Heavy (>150lbs) | 1-2 | 1-2 |
| Enduro/DH | Light (<150lbs) | 1-2 | 1-2 |
| Enduro/DH | Heavy (>150lbs) | 2-3 | 2-3 |
3. Rebound Damping Explained
Rebound damping controls how quickly your suspension returns to its extended position after compression. This setting is crucial for both control and traction:
Proper Rebound Setting Indicators:
- Bike should return smoothly without bouncing after large impacts
- Front wheel should stay in contact with ground through successive bumps
- Bike shouldn't feel like it's "pushing back" too quickly
- Suspension should extend fully before the next impact
Temperature Considerations:
- Damping oil becomes thinner at higher temperatures
- May need to increase damping on hot days
- Consider reducing damping in cold conditions
- Allow suspension to warm up before final adjustments
4. Compression Damping Settings
Compression damping controls how your suspension resists compression forces. Modern suspension often features multiple compression adjustments:
Low-Speed Compression (LSC):
- Controls suspension during rider weight shifts
- Affects brake dive and pedaling platform
- Important for climbing efficiency
- Typically adjusted in smaller increments
High-Speed Compression (HSC):
- Controls suspension during sudden impacts
- Affects bottom-out resistance
- Important for big hits and drops
- Usually requires larger adjustments
Advanced Suspension Topics
1. Suspension Kinematics
Understanding how your bike's suspension design affects its behavior can help you optimize your setup:
- Anti-Squat: How the suspension resists pedaling forces
- Leverage Ratio: How much shock stroke is used per mm of wheel travel
- Axle Path: The path your rear wheel follows through its travel
- Anti-Rise: How the suspension behaves under braking
2. Shock Technology Types
| Technology | Description | Best For |
|---|---|---|
| Air Spring | Lightweight, highly adjustable | XC, Trail, Enduro |
| Coil Spring | Linear, consistent feel | Enduro, Downhill |
| Hybrid Air/Coil | Combines benefits of both | Trail, Enduro |
| Electronic | Automatic adjustment | All disciplines |
Troubleshooting Common Issues
| Symptom | Possible Cause | Solution |
|---|---|---|
| Frequent Bottom Out | Too little air pressure or progression | Increase pressure or add volume spacers |
| Harsh on Small Bumps | Too much air pressure or compression | Reduce pressure or compression damping |
| Wallowing Mid-Stroke | Insufficient progression or compression | Add volume spacers or increase LSC |
| Bouncy After Impacts | Rebound too fast | Increase rebound damping |
| Packing Down on Repeated Hits | Rebound too slow | Decrease rebound damping |
Maintenance Tips for Optimal Performance
- Regular Cleaning: Wipe stanchions after every ride
- Lower Leg Service: Every 50 hours of riding
- Full Service: Every 100-200 hours depending on conditions
- Air Spring Service: Every 100 hours of riding
- Damper Service: Annually or every 100 hours
Environmental Considerations
Different conditions require different suspension setups:
| Condition | Adjustment Needed | Reason |
|---|---|---|
| Cold Weather | Reduce damping | Oil becomes thicker |
| Hot Weather | Increase damping | Oil becomes thinner |
| Wet Conditions | Reduce rebound | Less friction in system |
| High Altitude | Reduce air pressure | Air spring effect increases |
Recording Your Settings
Keep track of your suspension settings for different conditions and riding styles. Note the following:
- Air pressure in fork and shock
- Number of volume spacers
- Rebound clicks from closed
- Compression settings (LSC and HSC if applicable)
- Conditions and terrain type
- Notes on how the bike performed
Frequently Asked Questions About Bike Suspension
Basic Suspension Questions
How often should I check my suspension settings?
You should check your suspension settings:
- Before every big ride or race
- After significant temperature changes (±20°F/10°C)
- Monthly for regular riders
- When changing between significantly different terrain types
- After any suspension service
Why does my suspension feel different than when it was new?
Several factors can cause changes in suspension feel:
- Normal break-in period (first 10-20 hours)
- Seals wearing in and reducing friction
- Oil degradation over time
- Air can lubricant migration
- Changes in bushing clearance
Regular maintenance and service intervals help maintain consistent performance.
Should I adjust my suspension for different trails?
Yes, different trails often benefit from different settings:
| Trail Type | Recommended Adjustments |
|---|---|
| Smooth, Fast Trails | Firmer compression, faster rebound |
| Rocky, Technical | Softer compression, slower rebound |
| Jump Trails | More progression, faster rebound |
| Bike Park | More compression, balanced rebound |
Technical Questions
What's the difference between high-speed and low-speed compression?
High-speed and low-speed compression refer to the speed of suspension movement, not riding speed:
| Type | When It Works | What It Affects |
|---|---|---|
| Low-Speed Compression | Rider weight shifts, braking, pedaling | Support, pedaling efficiency, brake dive |
| High-Speed Compression | Sharp impacts, landing jumps, big hits | Impact absorption, bottom-out resistance |
Should I use tokens/volume spacers?
Volume spacers are useful for:
- Heavier riders needing more progression
- Aggressive riders wanting bottom-out resistance
- Riders frequently hitting jumps or drops
- Fine-tuning the suspension's end-stroke
General guidelines for volume spacers:
| Riding Style | Recommended Spacers | Benefits |
|---|---|---|
| XC Racing | 0-1 | Maintain sensitivity |
| Trail Riding | 1-2 | Balance support and plush |
| Enduro/Park | 2-3 | Bottom-out resistance |
| Big Hits/Jumps | 3-4 | Maximum progression |
Air vs. Coil: Which is better for my riding?
The choice between air and coil suspension depends on several factors:
| Aspect | Air Suspension | Coil Suspension |
|---|---|---|
| Weight | Lighter | Heavier |
| Maintenance | More frequent | Less frequent |
| Feel | Progressive | Linear |
| Adjustability | More adjustable | Less adjustable |
| Small bump sensitivity | Good | Excellent |
Maintenance Questions
How do I know when my suspension needs service?
Watch for these warning signs:
- Visible oil on stanchions or shock shaft
- Unusual noises (squelching, knocking)
- Inconsistent damping performance
- Sticky or notchy feeling
- Air loss between rides
- Changes in sag without pressure changes
What basic maintenance can I do myself?
Regular maintenance you can perform:
- Clean and inspect stanchions after rides
- Check and adjust air pressure
- Clean and lubricate air shaft seals
- Inspect for loose bolts or mounting hardware
- Check for proper sag and rebound settings
Leave these to professionals:
- Damper service or rebuilds
- Air spring rebuilds
- Seal replacement
- Internal lubrication service
What tools do I need for basic suspension maintenance?
Essential tools for suspension maintenance:
- Shock pump with accurate gauge
- Suspension-specific grease
- Clean microfiber cloths
- Suspension cleaner fluid
- Seal picks (for cleaning, not removal)
- Allen/hex key set
Troubleshooting Questions
Why is my suspension making noise?
Different noises can indicate different issues:
| Noise Type | Possible Cause | Solution |
|---|---|---|
| Squeaking | Dry bushings or seals | Clean and lubricate |
| Knocking | Loose hardware or headset | Check and tighten |
| Squelching | Air in damper | Need professional service |
| Clunking | Worn bushings | Replace bushings |
Why does my suspension feel harsh?
Harsh suspension can be caused by:
- Too much air pressure
- Excessive compression damping
- Rebound set too slow
- Dirty or dry seals
- Need for service
- Incorrect sag setting
Systematic troubleshooting steps:
- Check and reset sag to recommended values
- Open compression damping fully
- Set rebound to recommended setting
- Test ride and adjust one setting at a time
Why am I not using full travel?
Several factors can prevent full travel use:
- Too much air pressure
- Too many volume spacers
- Excessive compression damping
- Riding style or terrain not demanding enough
Note: Not using full travel on every ride is normal. Save some travel for unexpected impacts.
Setup and Performance Questions
How do temperature changes affect my suspension?
Temperature affects suspension in several ways:
- Air pressure increases in hot weather
- Damping oil becomes thinner when hot
- Cold temperatures increase damping
- Seals may become stiffer in cold
Adjustment guidelines for temperature changes:
| Temperature Change | Recommended Adjustment |
|---|---|
| Hot (+20°F/10°C) | Increase damping, check pressure |
| Cold (-20°F/10°C) | Decrease damping, check pressure |
How do I set up suspension for different riding weights?
When riding weight changes (gear, water, etc.):
- Calculate total riding weight including gear
- Adjust air pressure proportionally
- Fine-tune compression if needed
- Consider different volume spacer setups
What's the best way to test suspension settings?
Follow this testing procedure:
- Find a consistent test trail section
- Change only one setting at a time
- Make notes after each run
- Test multiple times to confirm results
- Include various terrain features
Key aspects to evaluate:
- Small bump sensitivity
- Mid-stroke support
- Bottom-out resistance
- Traction in corners
- Brake dive control