### 1. **Frame and Geometry** - **Durable Frame Materials**: Typically made from aluminum, carbon fiber, or steel for durability and lightweight performance; carbon fiber frames are lighter but more expensive. - **Trail-Optimized Geometry**: Longer wheelbase and slacker head tube angles provide stability on steep descents and better control over rough trails. ### 2. **Suspension System** - **Hardtail vs. Full-Suspension**: - *Hardtail*: Only front suspension (suspension fork), which provides shock absorption in the front, making it lighter and generally more affordable. - *Full-Suspension*: Both front and rear suspension, offering better shock absorption on rough terrains for improved control and comfort. - **Travel Range**: Suspension travel (amount the suspension moves) varies by bike type, generally from 80-100mm for cross-country bikes to 150-200mm for downhill bikes, allowing the bike to handle impacts. ### 3. **Tires and Wheels** - **Wider, Knobby Tires**: Mountain bike tires are wider and have aggressive tread patterns for better grip on dirt, mud, and rocky terrain. - **Tubeless Option**: Many MTBs offer tubeless-ready wheels and tires, which reduce the risk of flats and allow lower tire pressures for improved traction. - **Wheel Sizes (26", 27.5", 29")**: - *26-inch*: Compact and maneuverable, though less common in newer models. - *27.5-inch (650B)*: Provides a balance between agility and rollover ability. - *29-inch*: Larger wheels that roll over obstacles more easily, providing better stability on rough trails. ### 4. **Gearing and Drivetrain** - **Wide Gear Range**: MTBs typically come with a broad range of gears to handle steep inclines and fast descents, usually with 1x (single front chainring) setups for simplicity and efficiency. - **Rear Derailleur Clutch**: Many mountain bikes have a derailleur clutch that keeps the chain stable over rough terrain, reducing chain slap and the likelihood of dropping the chain. ### 5. **Brakes** - **Hydraulic Disc Brakes**: Preferred for reliable stopping power and control, especially in wet or muddy conditions; some entry-level bikes may still have mechanical disc brakes. - **Large Rotors**: Bigger rotors (160-203mm) provide better braking performance, especially on long, technical descents. ### 6. **Handlebars and Controls** - **Wide Handlebars**: Provide better control and stability on rough terrain by offering more leverage for steering. - **Shorter Stem**: A shorter stem places the rider in a more upright and balanced position, improving control, especially on descents. ### 7. **Dropper Seat Post** - **Adjustable Height**: Many mountain bikes come with a dropper post, which allows the rider to adjust the seat height on the fly, lowering it for descents and raising it for climbs, all at the push of a button. ### 8. **Pedals and Footing** - **Flat or Clipless Pedals**: - *Flat Pedals*: Wider and grippier, allowing quick foot placement or removal—often preferred by beginners or those on technical trails. - *Clipless Pedals*: Provide efficient power transfer but require special shoes, suitable for experienced riders who want maximum control. ### 9. **Protection and Durability Features** - **Chain Guards and Bash Guards**: Protect the chain and chainring from rocks or obstacles. - **Frame Protection**: Many MTBs have protective padding on key areas like the bottom tube and chainstay to prevent damage from rocks or debris.