A MTB rear shock works by combining a spring and a damper to control the movement of the rear wheel, improving traction, braking, and ride comfort.
Here's a breakdown of the components and their functions:
Components of a Rear Shock
-
Spring: Provides resistance to compression and determines the spring rate (how much force is required to compress the shock). There are two main types:
- Coil Spring: A metal coil that compresses. Known for linear feel and durability.
- Air Spring: Uses compressed air as the spring. Offers adjustability for different rider weights and riding styles.
-
Damper: Controls the speed at which the shock compresses (compression damping) and rebounds (rebound damping). This prevents the suspension from bouncing excessively. Dampers use oil forced through small orifices to create resistance.
Functionality
- Impact Absorption: When the rear wheel encounters a bump, the shock compresses, absorbing the impact.
- Spring Compression: The spring provides the initial resistance to the impact. The amount the spring compresses depends on the size of the bump and the spring rate.
- Damping Control: The damper controls the rate of compression and rebound.
- Compression Damping: Slows down the compression of the shock, preventing it from bottoming out on large impacts or wallowing during pedaling.
- Rebound Damping: Controls how quickly the shock returns to its extended position. Too little rebound damping will cause the bike to feel bouncy; too much will cause it to pack up (not extend fully between bumps).
- Maintaining Traction: By controlling the movement of the rear wheel, the shock helps maintain tire contact with the ground, maximizing traction for climbing, descending, and braking.
- Improving Ride Comfort: The shock absorbs vibrations and bumps, resulting in a smoother and more comfortable ride.
Types of Springs
| Feature | Coil Spring | Air Spring |
|---|---|---|
| Weight | Heavier | Lighter |
| Linearity | More Linear | More Progressive (adjustable) |
| Adjustability | Less adjustable | More adjustable |
| Durability | High | High |
| Maintenance | Lower | Higher |
Why is this important?
Without a rear shock (or with a poorly functioning one), a mountain bike would be difficult to control, uncomfortable to ride, and would lack traction on uneven terrain. A properly tuned rear shock significantly enhances the overall riding experience.
