Here’s a clear explanation of why a constant mesh gearbox (or “mesh gearbox”) is often chosen in automobiles:
🏎 Reasons to Choose a Constant Mesh Gearbox
1️⃣ Prevents Gear Grinding
- In older sliding-mesh gearboxes, gears physically slide to engage → high risk of gear clash or grinding if not timed perfectly.
- In a constant mesh gearbox, all gears are always meshed, and only the dog clutch engages the selected gear.
- Result: smoother, safer shifting.
2️⃣ Smoother Gear Shifting
- Only the dog clutch moves to engage a gear.
- Reduced friction and easier engagement → comfortable driving experience.
- Can be combined with synchromesh for even smoother shifts.
3️⃣ Longer Gear Life
- Constant meshing reduces wear and tear on gear teeth.
- No repeated sliding of large gear faces → durable and reliable for long-term use.
4️⃣ Compact and Efficient Design
- Uses a single layshaft and main shaft arrangement.
- Multiple gear ratios can be provided in a compact space.
- Lightweight compared to equivalent sliding-mesh systems for the same number of gears.
5️⃣ Easier to Operate
- Requires less skill than sliding-mesh gearbox.
- Modern versions with synchromesh allow almost clutchless gear engagement at low speeds (reduces driver fatigue).
6️⃣ Flexibility in Gear Ratios
- Can easily accommodate 4, 5, or more forward gears.
- Allows for optimal torque at low speed and fuel efficiency at high speed.
✅ Summary
You choose a constant mesh gearbox because it:
- Prevents gear grinding
- Ensures smooth gear shifts
- Increases gear durability
- Is compact and efficient
- Easier for drivers to operate
- Provides flexible gear ratios for different driving conditions
Other courses:


